ASP.NET Core搭建多层网站架构【4-工作单元和仓储设计】
2020/01/28, ASP.NET Core 3.1, VS2019, Microsoft.EntityFrameworkCore.Relational 3.1.1
摘要：基于ASP.NET Core 3.1 WebApi搭建后端多层网站架构【4-工作单元和仓储设计】
使用泛型仓储(Repository)和工作单元(UnitOfWork)模式封装数据访问层基础的增删改查等方法
关于本章节的工作单元模式：
泛型仓储封装了通用的增删改查方法，由工作单元统一管理仓储以保证数据库上下文一致性。
要获取仓储，都从工作单元中获取，通过仓储改动数据库后，由工作单元进行提交。
代码参考Arch/UnitOfWork的设计，大部分都是参考他的，然后做了一些中文注释，去除了分布式多库支持
添加包引用
向MS.UnitOfWork项目添加对Microsoft.EntityFrameworkCore.Relational包的引用：
<ItemGroup>
<PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="3.1.1" />
</ItemGroup>
分页处理封装
在MS.UnitOfWork项目中添加Collections文件夹，在该文件夹下添加IPagedList.cs、PagedList.cs、IEnumerablePagedListExtensions.cs、IQueryablePageListExtensions.cs类。
IPagedList.cs
using System.Collections.Generic;
namespace MS.UnitOfWork.Collections
{
/// <summary>
/// 提供任何类型的分页接口
/// </summary>
/// <typeparam name="T">需要分页的数据类型</typeparam>
public interface IPagedList<T>
{
/// <summary>
/// 起始页 值
/// </summary>
int IndexFrom { get; }
/// <summary>
/// 当前页 值
/// </summary>
int PageIndex { get; }
/// <summary>
/// 每页大小
/// </summary>
int PageSize { get; }
/// <summary>
/// 数据总数
/// </summary>
int TotalCount { get; }
/// <summary>
/// 总页数
/// </summary>
int TotalPages { get; }
/// <summary>
/// 当前页数据
/// </summary>
IList<T> Items { get; }
/// <summary>
/// 是否有上一页
/// </summary>
bool HasPreviousPage { get; }
/// <summary>
/// 是否有下一页
/// </summary>
bool HasNextPage { get; }
}
}
PagedList.cs
using System;
using System.Collections.Generic;
using System.Linq;
namespace MS.UnitOfWork.Collections
{
/// <summary>
/// 提供数据的分页，<see cref="IPagedList{T}"/>的默认实现
/// </summary>
/// <typeparam name="T"></typeparam>
public class PagedList<T> : IPagedList<T>
{
/// <summary>
/// 当前页 值
/// </summary>
public int PageIndex { get; set; }
/// <summary>
/// 每页大小
/// </summary>
public int PageSize { get; set; }
/// <summary>
/// 数据总数
/// </summary>
public int TotalCount { get; set; }
/// <summary>
/// 总页数
/// </summary>
public int TotalPages { get; set; }
/// <summary>
/// 起始页 值
/// </summary>
public int IndexFrom { get; set; }
/// <summary>
/// 当前页数据
/// </summary>
public IList<T> Items { get; set; }
/// <summary>
/// 是否有上一页
/// </summary>
public bool HasPreviousPage => PageIndex - IndexFrom > 0;
/// <summary>
/// 是否有下一页
/// </summary>
public bool HasNextPage => PageIndex - IndexFrom + 1 < TotalPages;
/// <summary>
/// 初始化实例
/// </summary>
/// <param name="source">The source.</param>
/// <param name="pageIndex">The index of the page.</param>
/// <param name="pageSize">The size of the page.</param>
/// <param name="indexFrom">The index from.</param>
internal PagedList(IEnumerable<T> source, int pageIndex, int pageSize, int indexFrom)
{
if (indexFrom > pageIndex)
{
throw new ArgumentException($"indexFrom: {indexFrom} > pageIndex: {pageIndex},起始页必须小于等于当前页");
}
if (source is IQueryable<T> querable)
{
PageIndex = pageIndex;
PageSize = pageSize;
IndexFrom = indexFrom;
TotalCount = querable.Count();
TotalPages = (int)Math.Ceiling(TotalCount / (double)PageSize);
Items = querable.Skip((PageIndex - IndexFrom) * PageSize).Take(PageSize).ToList();
}
else
{
PageIndex = pageIndex;
PageSize = pageSize;
IndexFrom = indexFrom;
TotalCount = source.Count();
TotalPages = (int)Math.Ceiling(TotalCount / (double)PageSize);
Items = source.Skip((PageIndex - IndexFrom) * PageSize).Take(PageSize).ToList();
}
}
/// <summary>
/// Initializes a new instance of the <see cref="PagedList{T}" /> class.
/// </summary>
internal PagedList() => Items = new T[0];
}
/// <summary>
/// 提供数据的分页，并支持数据类型转换
/// </summary>
/// <typeparam name="TSource">数据源类型</typeparam>
/// <typeparam name="TResult">输出数据类型</typeparam>
internal class PagedList<TSource, TResult> : IPagedList<TResult>
{
/// <summary>
/// 当前页 值
/// </summary>
public int PageIndex { get; set; }
/// <summary>
/// 每页大小
/// </summary>
public int PageSize { get; set; }
/// <summary>
/// 数据总数
/// </summary>
public int TotalCount { get; set; }
/// <summary>
/// 总页数
/// </summary>
public int TotalPages { get; set; }
/// <summary>
/// 起始页 值
/// </summary>
public int IndexFrom { get; set; }
/// <summary>
/// 当前页数据
/// </summary>
public IList<TResult> Items { get; set; }
/// <summary>
/// 是否有上一页
/// </summary>
public bool HasPreviousPage => PageIndex - IndexFrom > 0;
/// <summary>
/// 是否有下一页
/// </summary>
public bool HasNextPage => PageIndex - IndexFrom + 1 < TotalPages;
/// <summary>
/// 初始化实例
/// </summary>
/// <param name="source">The source.</param>
/// <param name="converter">The converter.</param>
/// <param name="pageIndex">The index of the page.</param>
/// <param name="pageSize">The size of the page.</param>
/// <param name="indexFrom">The index from.</param>
public PagedList(IEnumerable<TSource> source, Func<IEnumerable<TSource>, IEnumerable<TResult>> converter, int pageIndex, int pageSize, int indexFrom)
{
if (indexFrom > pageIndex)
{
throw new ArgumentException($"indexFrom: {indexFrom} > pageIndex: {pageIndex},起始页必须小于等于当前页");
}
if (source is IQueryable<TSource> querable)
{
PageIndex = pageIndex;
PageSize = pageSize;
IndexFrom = indexFrom;
TotalCount = querable.Count();
TotalPages = (int)Math.Ceiling(TotalCount / (double)PageSize);
var items = querable.Skip((PageIndex - IndexFrom) * PageSize).Take(PageSize).ToArray();
Items = new List<TResult>(converter(items));
}
else
{
PageIndex = pageIndex;
PageSize = pageSize;
IndexFrom = indexFrom;
TotalCount = source.Count();
TotalPages = (int)Math.Ceiling(TotalCount / (double)PageSize);
var items = source.Skip((PageIndex - IndexFrom) * PageSize).Take(PageSize).ToArray();
Items = new List<TResult>(converter(items));
}
}
/// <summary>
/// Initializes a new instance of the <see cref="PagedList{TSource, TResult}" /> class.
/// </summary>
/// <param name="source">The source.</param>
/// <param name="converter">The converter.</param>
public PagedList(IPagedList<TSource> source, Func<IEnumerable<TSource>, IEnumerable<TResult>> converter)
{
PageIndex = source.PageIndex;
PageSize = source.PageSize;
IndexFrom = source.IndexFrom;
TotalCount = source.TotalCount;
TotalPages = source.TotalPages;
Items = new List<TResult>(converter(source.Items));
}
}
/// <summary>
/// Provides some help methods for <see cref="IPagedList{T}"/> interface.
/// </summary>
public static class PagedList
{
/// <summary>
/// Creates an empty of <see cref="IPagedList{T}"/>.
/// </summary>
/// <typeparam name="T">The type for paging </typeparam>
/// <returns>An empty instance of <see cref="IPagedList{T}"/>.</returns>
public static IPagedList<T> Empty<T>() => new PagedList<T>();
/// <summary>
/// Creates a new instance of <see cref="IPagedList{TResult}"/> from source of <see cref="IPagedList{TSource}"/> instance.
/// </summary>
/// <typeparam name="TResult">The type of the result.</typeparam>
/// <typeparam name="TSource">The type of the source.</typeparam>
/// <param name="source">The source.</param>
/// <param name="converter">The converter.</param>
/// <returns>An instance of <see cref="IPagedList{TResult}"/>.</returns>
public static IPagedList<TResult> From<TResult, TSource>(IPagedList<TSource> source, Func<IEnumerable<TSource>, IEnumerable<TResult>> converter) => new PagedList<TSource, TResult>(source, converter);
}
}
IEnumerablePagedListExtensions.cs
using System;
using System.Collections.Generic;
namespace MS.UnitOfWork.Collections
{
/// <summary>
/// 给<see cref="IEnumerable{T}"/>添加扩展方法来支持分页
/// </summary>
public static class IEnumerablePagedListExtensions
{
/// <summary>
/// 在数据中取得固定页的数据
/// </summary>
/// <typeparam name="T">数据类型</typeparam>
/// <param name="source">数据源</param>
/// <param name="pageIndex">当前页</param>
/// <param name="pageSize">页大小</param>
/// <param name="indexFrom">起始页</param>
/// <returns></returns>
public static IPagedList<T> ToPagedList<T>(this IEnumerable<T> source, int pageIndex, int pageSize, int indexFrom = 1) => new PagedList<T>(source, pageIndex, pageSize, indexFrom);
/// <summary>
/// 在数据中取得固定页数据，并转换为指定数据类型
/// </summary>
/// <typeparam name="TSource">数据源类型</typeparam>
/// <typeparam name="TResult">输出数据类型</typeparam>
/// <param name="source">数据源</param>
/// <param name="converter"></param>
/// <param name="pageIndex">当前页</param>
/// <param name="pageSize">页大小</param>
/// <param name="indexFrom">起始页</param>
/// <returns></returns>
public static IPagedList<TResult> ToPagedList<TSource, TResult>(this IEnumerable<TSource> source, Func<IEnumerable<TSource>, IEnumerable<TResult>> converter, int pageIndex, int pageSize, int indexFrom = 1) => new PagedList<TSource, TResult>(source, converter, pageIndex, pageSize, indexFrom);
}
}
IQueryablePageListExtensions.cs
using Microsoft.EntityFrameworkCore;
using System;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
namespace MS.UnitOfWork.Collections
{
public static class IQueryablePageListExtensions
{
/// <summary>
/// 在数据中取得固定页的数据（异步操作）
/// </summary>
/// <typeparam name="T">数据类型</typeparam>
/// <param name="source">数据源</param>
/// <param name="pageIndex">当前页</param>
/// <param name="pageSize">页大小</param>
/// <param name="indexFrom">起始页</param>
/// <param name="cancellationToken">异步观察参数</param>
/// <returns></returns>
public static async Task<IPagedList<T>> ToPagedListAsync<T>(this IQueryable<T> source, int pageIndex, int pageSize, int indexFrom = 1, CancellationToken cancellationToken = default(CancellationToken))
{
if (indexFrom > pageIndex)
{
throw new ArgumentException($"indexFrom: {indexFrom} > pageIndex: {pageIndex}, must indexFrom <= pageIndex");
}
var count = await source.CountAsync(cancellationToken).ConfigureAwait(false);
var items = await source.Skip((pageIndex - indexFrom) * pageSize)
.Take(pageSize).ToListAsync(cancellationToken).ConfigureAwait(false);
var pagedList = new PagedList<T>()
{
PageIndex = pageIndex,
PageSize = pageSize,
IndexFrom = indexFrom,
TotalCount = count,
Items = items,
TotalPages = (int)Math.Ceiling(count / (double)pageSize)
};
return pagedList;
}
}
}
针对IQueryable、IEnumerable类型的数据做了分页扩展方法封装，主要用于向数据库获取数据时进行分页筛选
泛型仓储
在MS.UnitOfWork项目中添加Repository文件夹，在该文件夹下添加IRepository.cs、Repository.cs类。
IRepository.cs
using MS.UnitOfWork.Collections;
using Microsoft.EntityFrameworkCore.ChangeTracking;
using Microsoft.EntityFrameworkCore.Query;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Threading;
using System.Threading.Tasks;
namespace MS.UnitOfWork
{
/// <summary>
/// 通用仓储接口
/// </summary>
/// <typeparam name="TEntity"></typeparam>
public interface IRepository<TEntity> where TEntity : class
{
#region GetAll
/// <summary>
///获取所有实体
///注意性能！
/// </summary>
/// <returns>The <see cref="IQueryable{TEntity}"/>.</returns>
IQueryable<TEntity> GetAll();
/// <summary>
/// 获取所有实体
/// </summary>
/// <param name="predicate">条件表达式</param>
/// <param name="orderBy">排序</param>
/// <param name="include">包含的导航属性</param>
/// <param name="disableTracking">设置为true关闭追踪查询。默认为true</param>
/// <param name="ignoreQueryFilters">设置为true忽略全局查询筛选过滤。默认为false</param>
/// <returns></returns>
IQueryable<TEntity> GetAll(
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false);
/// <summary>
/// 获取所有实体，必须提供筛选谓词
/// </summary>
/// <typeparam name="TResult">输出数据类型</typeparam>
/// <param name="selector">投影选择器</param>
/// <param name="predicate">筛选谓词</param>
/// <param name="orderBy">排序</param>
/// <param name="include">包含的导航属性</param>
/// <param name="disableTracking">设置为true关闭追踪查询。默认为true</param>
/// <returns></returns>
IQueryable<TResult> GetAll<TResult>(
Expression<Func<TEntity, TResult>> selector,
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false
) where TResult : class;
/// <summary>
/// 获取所有实体
/// </summary>
/// <param name="predicate">条件表达式</param>
/// <param name="orderBy">排序</param>
/// <param name="include">包含的导航属性</param>
/// <param name="disableTracking">设置为true关闭追踪查询。默认为true</param>
/// <param name="ignoreQueryFilters">设置为true忽略全局查询筛选过滤。默认为false</param>
/// <returns></returns>
Task<IList<TEntity>> GetAllAsync(
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false);
#endregion
#region GetPagedList
/// <summary>
/// 获取分页数据
/// 默认是关闭追踪查询的（拿到的数据默认只读）
/// 默认开启全局查询筛选过滤
/// </summary>
/// <param name="predicate">条件表达式</param>
/// <param name="orderBy">排序</param>
/// <param name="include">包含的导航属性</param>
/// <param name="pageIndex">当前页。默认第一页</param>
/// <param name="pageSize">页大小。默认20笔数据</param>
/// <param name="disableTracking">设置为true关闭追踪查询。默认为true</param>
/// <param name="ignoreQueryFilters">设置为true忽略全局查询筛选过滤。默认为false</param>
/// <returns></returns>
IPagedList<TEntity> GetPagedList(
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
int pageIndex = 1,
int pageSize = 20,
bool disableTracking = true,
bool ignoreQueryFilters = false);
/// <summary>
/// 获取分页数据
/// 默认是关闭追踪查询的（拿到的数据默认只读）
/// 默认开启全局查询筛选过滤
/// </summary>
/// <param name="predicate">条件表达式</param>
/// <param name="orderBy">排序</param>
/// <param name="include">包含的导航属性</param>
/// <param name="pageIndex">当前页。默认第一页</param>
/// <param name="pageSize">页大小。默认20笔数据</param>
/// <param name="disableTracking">设置为true关闭追踪查询。默认为true</param>
/// <param name="ignoreQueryFilters">设置为true忽略全局查询筛选过滤。默认为false</param>
/// <param name="cancellationToken">异步token</param>
/// <returns></returns>
Task<IPagedList<TEntity>> GetPagedListAsync(
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
int pageIndex = 1,
int pageSize = 20,
bool disableTracking = true,
bool ignoreQueryFilters = false,
CancellationToken cancellationToken = default);
/// <summary>
/// 获取分页数据
/// 默认是关闭追踪查询的（拿到的数据默认只读）
/// 默认开启全局查询筛选过滤
/// </summary>
/// <typeparam name="TResult">输出数据类型</typeparam>
/// <param name="selector">投影选择器</param>
/// <param name="predicate">条件表达式</param>
/// <param name="orderBy">排序</param>
/// <param name="include">包含的导航属性</param>
/// <param name="pageIndex">当前页。默认第一页</param>
/// <param name="pageSize">页大小。默认20笔数据</param>
/// <param name="disableTracking">设置为true关闭追踪查询。默认为true</param>
/// <param name="ignoreQueryFilters">设置为true忽略全局查询筛选过滤。默认为false</param>
/// <returns></returns>
IPagedList<TResult> GetPagedList<TResult>(
Expression<Func<TEntity, TResult>> selector,
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
int pageIndex = 1,
int pageSize = 20,
bool disableTracking = true,
bool ignoreQueryFilters = false
) where TResult : class;
/// <summary>
/// 获取分页数据
/// 默认是关闭追踪查询的（拿到的数据默认只读）
/// 默认开启全局查询筛选过滤
/// </summary>
/// <typeparam name="TResult">输出数据类型</typeparam>
/// <param name="selector">投影选择器</param>
/// <param name="predicate">条件表达式</param>
/// <param name="orderBy">排序</param>
/// <param name="include">包含的导航属性</param>
/// <param name="pageIndex">当前页。默认第一页</param>
/// <param name="pageSize">页大小。默认20笔数据</param>
/// <param name="disableTracking">设置为true关闭追踪查询。默认为true</param>
/// <param name="ignoreQueryFilters">设置为true忽略全局查询筛选过滤。默认为false</param>
/// <param name="cancellationToken">异步token</param>
/// <returns></returns>
Task<IPagedList<TResult>> GetPagedListAsync<TResult>(
Expression<Func<TEntity, TResult>> selector,
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
int pageIndex = 1,
int pageSize = 20,
bool disableTracking = true,
bool ignoreQueryFilters = false,
CancellationToken cancellationToken = default) where TResult : class;
#endregion
#region GetFirstOrDefault
/// <summary>
/// 获取满足条件的序列中的第一个元素
/// 如果没有元素满足条件，则返回默认值
/// 默认是关闭追踪查询的（拿到的数据默认只读）
/// 默认开启全局查询筛选过滤
/// </summary>
/// <param name="predicate">条件表达式</param>
/// <param name="orderBy">排序</param>
/// <param name="include">包含的导航属性</param>
/// <param name="disableTracking">设置为true关闭追踪查询。默认为true</param>
/// <param name="ignoreQueryFilters">设置为true忽略全局查询筛选过滤。默认为false</param>
/// <returns></returns>
TEntity GetFirstOrDefault(
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false);
/// <summary>
/// 获取满足条件的序列中的第一个元素
/// 如果没有元素满足条件，则返回默认值
/// 默认是关闭追踪查询的（拿到的数据默认只读）
/// 默认开启全局查询筛选过滤
/// </summary>
/// <param name="predicate">条件表达式</param>
/// <param name="orderBy">排序</param>
/// <param name="include">包含的导航属性</param>
/// <param name="disableTracking">设置为true关闭追踪查询。默认为true</param>
/// <param name="ignoreQueryFilters">设置为true忽略全局查询筛选过滤。默认为false</param>
/// <param name="cancellationToken">异步token</param>
/// <returns></returns>
Task<TEntity> GetFirstOrDefaultAsync(
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false,
CancellationToken cancellationToken = default);
/// <summary>
/// 获取满足条件的序列中的第一个元素
/// 如果没有元素满足条件，则返回默认值
/// 默认是关闭追踪查询的（拿到的数据默认只读）
/// 默认开启全局查询筛选过滤
/// </summary>
/// <typeparam name="TResult">输出数据类型</typeparam>
/// <param name="selector">投影选择器</param>
/// <param name="predicate">条件表达式</param>
/// <param name="orderBy">排序</param>
/// <param name="include">包含的导航属性</param>
/// <param name="disableTracking">设置为true关闭追踪查询。默认为true</param>
/// <param name="ignoreQueryFilters">设置为true忽略全局查询筛选过滤。默认为false</param>
/// <returns></returns>
TResult GetFirstOrDefault<TResult>(
Expression<Func<TEntity, TResult>> selector,
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false);
/// <summary>
/// 获取满足条件的序列中的第一个元素
/// 如果没有元素满足条件，则返回默认值
/// 默认是关闭追踪查询的（拿到的数据默认只读）
/// 默认开启全局查询筛选过滤
/// </summary>
/// <typeparam name="TResult">输出数据类型</typeparam>
/// <param name="selector">投影选择器</param>
/// <param name="predicate">条件表达式</param>
/// <param name="orderBy">排序</param>
/// <param name="include">包含的导航属性</param>
/// <param name="disableTracking">设置为true关闭追踪查询。默认为true</param>
/// <param name="ignoreQueryFilters">设置为true忽略全局查询筛选过滤。默认为false</param>
/// <param name="cancellationToken">异步token</param>
/// <returns></returns>
Task<TResult> GetFirstOrDefaultAsync<TResult>(
Expression<Func<TEntity, TResult>> selector,
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false,
CancellationToken cancellationToken = default);
#endregion
#region Find
/// <summary>
/// Finds an entity with the given primary key values. If found, is attached to the context and returned. If no entity is found, then null is returned.
/// </summary>
/// <param name="keyValues">The values of the primary key for the entity to be found.</param>
/// <returns>The found entity or null.</returns>
TEntity Find(params object[] keyValues);
/// <summary>
/// Finds an entity with the given primary key values. If found, is attached to the context and returned. If no entity is found, then null is returned.
/// </summary>
/// <param name="keyValues">The values of the primary key for the entity to be found.</param>
/// <returns>A <see cref="Task{TEntity}"/> that represents the asynchronous find operation. The task result contains the found entity or null.</returns>
ValueTask<TEntity> FindAsync(params object[] keyValues);
/// <summary>
/// Finds an entity with the given primary key values. If found, is attached to the context and returned. If no entity is found, then null is returned.
/// </summary>
/// <param name="keyValues">The values of the primary key for the entity to be found.</param>
/// <param name="cancellationToken">A <see cref="CancellationToken"/> to observe while waiting for the task to complete.</param>
/// <returns>A <see cref="Task{TEntity}"/> that represents the asynchronous find operation. The task result contains the found entity or null.</returns>
ValueTask<TEntity> FindAsync(object[] keyValues, CancellationToken cancellationToken);
#endregion
#region sql、count、exist
/// <summary>
/// 使用原生sql查询来获取指定数据
/// </summary>
/// <param name="sql"></param>
/// <param name="parameters"></param>
/// <returns></returns>
IQueryable<TEntity> FromSql(string sql, params object[] parameters);
/// <summary>
/// 查询数量
/// </summary>
/// <param name="predicate"></param>
/// <returns></returns>
int Count(Expression<Func<TEntity, bool>> predicate = null);
/// <summary>
/// 查询数量
/// </summary>
/// <param name="predicate"></param>
/// <returns></returns>
Task<int> CountAsync(Expression<Func<TEntity, bool>> predicate = null);
/// <summary>
/// 按指定条件元素是否存在
/// </summary>
/// <param name="predicate"></param>
/// <returns></returns>
bool Exists(Expression<Func<TEntity, bool>> predicate = null);
#endregion
#region Insert
/// <summary>
/// Inserts a new entity synchronously.
/// </summary>
/// <param name="entity"></param>
/// <returns></returns>
TEntity Insert(TEntity entity);
/// <summary>
/// Inserts a range of entities synchronously.
/// </summary>
/// <param name="entities">The entities to insert.</param>
void Insert(params TEntity[] entities);
/// <summary>
/// Inserts a range of entities synchronously.
/// </summary>
/// <param name="entities">The entities to insert.</param>
void Insert(IEnumerable<TEntity> entities);
/// <summary>
/// Inserts a new entity asynchronously.
/// </summary>
/// <param name="entity">The entity to insert.</param>
/// <param name="cancellationToken">A <see cref="CancellationToken"/> to observe while waiting for the task to complete.</param>
/// <returns>A <see cref="Task"/> that represents the asynchronous insert operation.</returns>
ValueTask<EntityEntry<TEntity>> InsertAsync(TEntity entity, CancellationToken cancellationToken = default);
/// <summary>
/// Inserts a range of entities asynchronously.
/// </summary>
/// <param name="entities">The entities to insert.</param>
/// <returns>A <see cref="Task"/> that represents the asynchronous insert operation.</returns>
Task InsertAsync(params TEntity[] entities);
/// <summary>
/// Inserts a range of entities asynchronously.
/// </summary>
/// <param name="entities">The entities to insert.</param>
/// <param name="cancellationToken">A <see cref="CancellationToken"/> to observe while waiting for the task to complete.</param>
/// <returns>A <see cref="Task"/> that represents the asynchronous insert operation.</returns>
Task InsertAsync(IEnumerable<TEntity> entities, CancellationToken cancellationToken = default);
#endregion
#region Update
/// <summary>
/// Updates the specified entity.
/// </summary>
/// <param name="entity">The entity.</param>
void Update(TEntity entity);
/// <summary>
/// Updates the specified entities.
/// </summary>
/// <param name="entities">The entities.</param>
void Update(params TEntity[] entities);
/// <summary>
/// Updates the specified entities.
/// </summary>
/// <param name="entities">The entities.</param>
void Update(IEnumerable<TEntity> entities);
#endregion
#region Delete
/// <summary>
/// Deletes the entity by the specified primary key.
/// </summary>
/// <param name="id">The primary key value.</param>
void Delete(object id);
/// <summary>
/// Deletes the specified entity.
/// </summary>
/// <param name="entity">The entity to delete.</param>
void Delete(TEntity entity);
/// <summary>
/// Deletes the specified entities.
/// </summary>
/// <param name="entities">The entities.</param>
void Delete(params TEntity[] entities);
/// <summary>
/// Deletes the specified entities.
/// </summary>
/// <param name="entities">The entities.</param>
void Delete(IEnumerable<TEntity> entities);
#endregion
}
}
Repository.cs
using MS.UnitOfWork.Collections;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.ChangeTracking;
using Microsoft.EntityFrameworkCore.Query;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
namespace MS.UnitOfWork
{
/// <summary>
/// 通用仓储的默认实现
/// </summary>
/// <typeparam name="TEntity"></typeparam>
public class Repository<TEntity> : IRepository<TEntity> where TEntity : class
{
protected readonly DbContext _dbContext;
protected readonly DbSet<TEntity> _dbSet;
public Repository(DbContext dbContext)
{
_dbContext = dbContext ?? throw new ArgumentNullException(nameof(dbContext));
_dbSet = _dbContext.Set<TEntity>();
}
#region GetAll
public IQueryable<TEntity> GetAll() => _dbSet;
public IQueryable<TEntity> GetAll(
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false)
{
IQueryable<TEntity> query = _dbSet;
if (disableTracking)
{
query = query.AsNoTracking();
}
if (include != null)
{
query = include(query);
}
if (predicate != null)
{
query = query.Where(predicate);
}
if (ignoreQueryFilters)
{
query = query.IgnoreQueryFilters();
}
if (orderBy != null)
{
return orderBy(query);
}
else
{
return query;
}
}
public IQueryable<TResult> GetAll<TResult>(
Expression<Func<TEntity, TResult>> selector,
Expression<Func<TEntity, bool>> predicate,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false) where TResult : class
{
IQueryable<TEntity> query = _dbSet;
if (disableTracking)
{
query = query.AsNoTracking();
}
if (include != null)
{
query = include(query);
}
if (predicate != null)
{
query = query.Where(predicate);
}
if (ignoreQueryFilters)
{
query = query.IgnoreQueryFilters();
}
if (orderBy != null)
{
return orderBy(query).Select(selector);
}
else
{
return query.Select(selector);
}
}
public async Task<IList<TEntity>> GetAllAsync(Expression<Func<TEntity, bool>> predicate = null, Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null, Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null, bool disableTracking = true, bool ignoreQueryFilters = false)
{
IQueryable<TEntity> query = _dbSet;
if (disableTracking)
{
query = query.AsNoTracking();
}
if (include != null)
{
query = include(query);
}
if (predicate != null)
{
query = query.Where(predicate);
}
if (ignoreQueryFilters)
{
query = query.IgnoreQueryFilters();
}
if (orderBy != null)
{
return await orderBy(query).ToListAsync();
}
else
{
return await query.ToListAsync();
}
}
#endregion
#region GetPagedList
public virtual IPagedList<TEntity> GetPagedList(
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
int pageIndex = 1,
int pageSize = 20,
bool disableTracking = true,
bool ignoreQueryFilters = false)
{
IQueryable<TEntity> query = _dbSet;
if (disableTracking)
{
query = query.AsNoTracking();
}
if (include != null)
{
query = include(query);
}
if (predicate != null)
{
query = query.Where(predicate);
}
if (ignoreQueryFilters)
{
query = query.IgnoreQueryFilters();
}
if (orderBy != null)
{
return orderBy(query).ToPagedList(pageIndex, pageSize);
}
else
{
return query.ToPagedList(pageIndex, pageSize);
}
}
public virtual async Task<IPagedList<TEntity>> GetPagedListAsync(
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
int pageIndex = 1,
int pageSize = 20,
bool disableTracking = true,
bool ignoreQueryFilters = false,
CancellationToken cancellationToken = default)
{
IQueryable<TEntity> query = _dbSet;
if (disableTracking)
{
query = query.AsNoTracking();
}
if (include != null)
{
query = include(query);
}
if (predicate != null)
{
query = query.Where(predicate);
}
if (ignoreQueryFilters)
{
query = query.IgnoreQueryFilters();
}
if (orderBy != null)
{
return await orderBy(query).ToPagedListAsync(pageIndex, pageSize, 1, cancellationToken);
}
else
{
return await query.ToPagedListAsync(pageIndex, pageSize, 1, cancellationToken);
}
}
public virtual IPagedList<TResult> GetPagedList<TResult>(
Expression<Func<TEntity, TResult>> selector,
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
int pageIndex = 1,
int pageSize = 20,
bool disableTracking = true,
bool ignoreQueryFilters = false)
where TResult : class
{
IQueryable<TEntity> query = _dbSet;
if (disableTracking)
{
query = query.AsNoTracking();
}
if (include != null)
{
query = include(query);
}
if (predicate != null)
{
query = query.Where(predicate);
}
if (ignoreQueryFilters)
{
query = query.IgnoreQueryFilters();
}
if (orderBy != null)
{
return orderBy(query).Select(selector).ToPagedList(pageIndex, pageSize);
}
else
{
return query.Select(selector).ToPagedList(pageIndex, pageSize);
}
}
public virtual async Task<IPagedList<TResult>> GetPagedListAsync<TResult>(
Expression<Func<TEntity, TResult>> selector,
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
int pageIndex = 1,
int pageSize = 20,
bool disableTracking = true,
bool ignoreQueryFilters = false,
CancellationToken cancellationToken = default)
where TResult : class
{
IQueryable<TEntity> query = _dbSet;
if (disableTracking)
{
query = query.AsNoTracking();
}
if (include != null)
{
query = include(query);
}
if (predicate != null)
{
query = query.Where(predicate);
}
if (ignoreQueryFilters)
{
query = query.IgnoreQueryFilters();
}
if (orderBy != null)
{
return await orderBy(query).Select(selector).ToPagedListAsync(pageIndex, pageSize, 1, cancellationToken);
}
else
{
return await query.Select(selector).ToPagedListAsync(pageIndex, pageSize, 1, cancellationToken);
}
}
#endregion
#region GetFirstOrDefault
public virtual TEntity GetFirstOrDefault(
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false)
{
IQueryable<TEntity> query = _dbSet;
if (disableTracking)
{
query = query.AsNoTracking();
}
if (include != null)
{
query = include(query);
}
if (predicate != null)
{
query = query.Where(predicate);
}
if (ignoreQueryFilters)
{
query = query.IgnoreQueryFilters();
}
if (orderBy != null)
{
return orderBy(query).FirstOrDefault();
}
else
{
return query.FirstOrDefault();
}
}
public virtual async Task<TEntity> GetFirstOrDefaultAsync(
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false,
CancellationToken cancellationToken = default)
{
IQueryable<TEntity> query = _dbSet;
if (disableTracking)
{
query = query.AsNoTracking();
}
if (include != null)
{
query = include(query);
}
if (predicate != null)
{
query = query.Where(predicate);
}
if (ignoreQueryFilters)
{
query = query.IgnoreQueryFilters();
}
if (orderBy != null)
{
return await orderBy(query).FirstOrDefaultAsync(cancellationToken);
}
else
{
return await query.FirstOrDefaultAsync(cancellationToken);
}
}
public virtual TResult GetFirstOrDefault<TResult>(
Expression<Func<TEntity, TResult>> selector,
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false)
{
IQueryable<TEntity> query = _dbSet;
if (disableTracking)
{
query = query.AsNoTracking();
}
if (include != null)
{
query = include(query);
}
if (predicate != null)
{
query = query.Where(predicate);
}
if (ignoreQueryFilters)
{
query = query.IgnoreQueryFilters();
}
if (orderBy != null)
{
return orderBy(query).Select(selector).FirstOrDefault();
}
else
{
return query.Select(selector).FirstOrDefault();
}
}
public virtual async Task<TResult> GetFirstOrDefaultAsync<TResult>(
Expression<Func<TEntity, TResult>> selector,
Expression<Func<TEntity, bool>> predicate = null,
Func<IQueryable<TEntity>, IOrderedQueryable<TEntity>> orderBy = null,
Func<IQueryable<TEntity>, IIncludableQueryable<TEntity, object>> include = null,
bool disableTracking = true,
bool ignoreQueryFilters = false,
CancellationToken cancellationToken = default)
{
IQueryable<TEntity> query = _dbSet;
if (disableTracking)
{
query = query.AsNoTracking();
}
if (include != null)
{
query = include(query);
}
if (predicate != null)
{
query = query.Where(predicate);
}
if (ignoreQueryFilters)
{
query = query.IgnoreQueryFilters();
}
if (orderBy != null)
{
return await orderBy(query).Select(selector).FirstOrDefaultAsync(cancellationToken);
}
else
{
return await query.Select(selector).FirstOrDefaultAsync(cancellationToken);
}
}
#endregion
#region Find
public virtual TEntity Find(params object[] keyValues) => _dbSet.Find(keyValues);
public virtual ValueTask<TEntity> FindAsync(params object[] keyValues) => _dbSet.FindAsync(keyValues);
public virtual ValueTask<TEntity> FindAsync(object[] keyValues, CancellationToken cancellationToken) => _dbSet.FindAsync(keyValues, cancellationToken);
#endregion
#region sql、count、exist
public virtual IQueryable<TEntity> FromSql(string sql, params object[] parameters) => _dbSet.FromSqlRaw(sql, parameters);
public virtual int Count(Expression<Func<TEntity, bool>> predicate = null)
{
if (predicate == null)
{
return _dbSet.Count();
}
else
{
return _dbSet.Count(predicate);
}
}
public virtual async Task<int> CountAsync(Expression<Func<TEntity, bool>> predicate = null)
{
if (predicate == null)
{
return await _dbSet.CountAsync();
}
else
{
return await _dbSet.CountAsync(predicate);
}
}
public virtual bool Exists(Expression<Func<TEntity, bool>> predicate = null)
{
if (predicate == null)
{
return _dbSet.Any();
}
else
{
return _dbSet.Any(predicate);
}
}
#endregion
#region Insert
public virtual TEntity Insert(TEntity entity)
{
return _dbSet.Add(entity).Entity;
}
public virtual void Insert(params TEntity[] entities) => _dbSet.AddRange(entities);
public virtual void Insert(IEnumerable<TEntity> entities) => _dbSet.AddRange(entities);
public virtual ValueTask<EntityEntry<TEntity>> InsertAsync(TEntity entity, CancellationToken cancellationToken = default(CancellationToken))
{
return _dbSet.AddAsync(entity, cancellationToken);
// Shadow properties?
//var property = _dbContext.Entry(entity).Property("Created");
//if (property != null) {
//property.CurrentValue = DateTime.Now;
//}
}
public virtual Task InsertAsync(params TEntity[] entities) => _dbSet.AddRangeAsync(entities);
public virtual Task InsertAsync(IEnumerable<TEntity> entities, CancellationToken cancellationToken = default(CancellationToken)) => _dbSet.AddRangeAsync(entities, cancellationToken);
#endregion
#region Update
public virtual void Update(TEntity entity)
{
_dbSet.Update(entity);
}
public virtual void UpdateAsync(TEntity entity)
{
_dbSet.Update(entity);
}
public virtual void Update(params TEntity[] entities) => _dbSet.UpdateRange(entities);
public virtual void Update(IEnumerable<TEntity> entities) => _dbSet.UpdateRange(entities);
#endregion
#region Delete
public virtual void Delete(TEntity entity) => _dbSet.Remove(entity);
public virtual void Delete(object id)
{
var entity = _dbSet.Find(id);
if (entity != null)
{
Delete(entity);
}
}
public virtual void Delete(params TEntity[] entities) => _dbSet.RemoveRange(entities);
public virtual void Delete(IEnumerable<TEntity> entities) => _dbSet.RemoveRange(entities);
#endregion
}
}
说明
- 封装了通用的增删改查操作
- 以Async方法名结尾的是异步操作
- 方法注释都在接口中
- 查询：
- GetAll查询所有满足条件的实体（注意性能）
- GetPagedList分页查询
- GetFirstOrDefault获取满足条件的第一个元素
- Find根据主键查找元素，比如给一个Id值
- FromSql原生sql查询
- Count查询数量
- Exists查询是否存在
- 查询中包含了很多条件：
- 分页查询默认每页20笔数据
- 默认关闭了追踪查询
- 默认开启了全局查询过滤
- selector参数可以转换查询出来的数据为其他类型
工作单元
在MS.UnitOfWork项目中添加UnitOfWork文件夹，在该文件夹下添加IUnitOfWork.cs、UnitOfWork.cs类。
IUnitOfWork.cs
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Storage;
using System;
using System.Linq;
using System.Threading.Tasks;
namespace MS.UnitOfWork
{
/// <summary>
/// 定义工作单元接口
/// </summary>
public interface IUnitOfWork<TContext> : IDisposable where TContext : DbContext
{
/// <summary>
/// 获取DBContext
/// </summary>
/// <returns></returns>
TContext DbContext { get; }
/// <summary>
/// 开始一个事务
/// </summary>
/// <returns></returns>
IDbContextTransaction BeginTransaction();
/// <summary>
/// 获取指定仓储
/// </summary>
/// <typeparam name="TEntity"></typeparam>
/// <param name="hasCustomRepository">如有自定义仓储设为True</param>
/// <returns></returns>
IRepository<TEntity> GetRepository<TEntity>(bool hasCustomRepository = false) where TEntity : class;
/// <summary>
/// DbContext提交修改
/// </summary>
/// <returns></returns>
int SaveChanges();
/// <summary>
/// DbContext提交修改（异步）
/// </summary>
/// <returns></returns>
Task<int> SaveChangesAsync();
/// <summary>
/// 执行原生sql语句
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="parameters">参数</param>
/// <returns></returns>
int ExecuteSqlCommand(string sql, params object[] parameters);
/// <summary>
/// 使用原生sql查询来获取指定数据
/// </summary>
/// <typeparam name="TEntity"></typeparam>
/// <param name="sql"></param>
/// <param name="parameters">参数</param>
/// <returns></returns>
IQueryable<TEntity> FromSql<TEntity>(string sql, params object[] parameters) where TEntity : class;
}
}
UnitOfWork.cs
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Infrastructure;
using Microsoft.EntityFrameworkCore.Storage;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace MS.UnitOfWork
{
/// <summary>
/// 工作单元的默认实现.
/// </summary>
/// <typeparam name="TContext"></typeparam>
public class UnitOfWork<TContext> : IUnitOfWork<TContext> where TContext : DbContext
{
protected readonly TContext _context;
protected bool _disposed = false;
protected Dictionary<Type, object> _repositories;
public UnitOfWork(TContext context)
{
_context = context ?? throw new ArgumentNullException(nameof(context));
}
/// <summary>
/// 获取DbContext
/// </summary>
public TContext DbContext => _context;
/// <summary>
/// 开始一个事务
/// </summary>
/// <returns></returns>
public IDbContextTransaction BeginTransaction()
{
return _context.Database.BeginTransaction();
}
/// <summary>
/// 获取指定仓储
/// </summary>
/// <typeparam name="TEntity"></typeparam>
/// <param name="hasCustomRepository"></param>
/// <returns></returns>
public IRepository<TEntity> GetRepository<TEntity>(bool hasCustomRepository = false) where TEntity : class
{
if (_repositories == null)
{
_repositories = new Dictionary<Type, object>();
}
Type type = typeof(IRepository<TEntity>);
if (!_repositories.TryGetValue(type, out object repo))
{
IRepository<TEntity> newRepo = new Repository<TEntity>(_context);
_repositories.Add(type, newRepo);
return newRepo;
}
return (IRepository<TEntity>)repo;
}
/// <summary>
/// 执行原生sql语句
/// </summary>
/// <param name="sql">sql语句</param>
/// <param name="parameters">参数</param>
/// <returns></returns>
public int ExecuteSqlCommand(string sql, params object[] parameters) => _context.Database.ExecuteSqlRaw(sql, parameters);
/// <summary>
/// 使用原生sql查询来获取指定数据
/// </summary>
/// <typeparam name="TEntity"></typeparam>
/// <param name="sql"></param>
/// <param name="parameters">参数</param>
/// <returns></returns>
public IQueryable<TEntity> FromSql<TEntity>(string sql, params object[] parameters) where TEntity : class => _context.Set<TEntity>().FromSqlRaw(sql, parameters);
/// <summary>
/// DbContext提交修改
/// </summary>
/// <returns></returns>
public int SaveChanges()
{
return _context.SaveChanges();
}
/// <summary>
/// DbContext提交修改（异步）
/// </summary>
/// <returns></returns>
public async Task<int> SaveChangesAsync()
{
return await _context.SaveChangesAsync();
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposing)
{
if (!_disposed)
{
if (disposing)
{
// clear repositories
if (_repositories != null)
{
_repositories.Clear();
}
// dispose the db context.
_context.Dispose();
}
}
_disposed = true;
}
}
}
说明
- 从工作单元中获取仓储或DbContext数据库上下文
- 如果要使用Transaction事务，也是从工作单元中开启
- 通过仓储修改数据后，使用工作单元SaveChanges提交修改
封装Ioc注册
在MS.UnitOfWork项目中添加UnitOfWorkServiceExtensions.cs类：
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
namespace MS.UnitOfWork
{
/// <summary>
///在 <see cref="IServiceCollection"/>中安装工作单元依赖注入的扩展方法
/// </summary>
public static class UnitOfWorkServiceExtensions
{
/// <summary>
/// 在<see cref ="IServiceCollection"/>中注册给定上下文作为服务的工作单元。
/// 同时注册了dbcontext
/// </summary>
/// <typeparam name="TContext"></typeparam>
/// <param name="services"></param>
/// <remarks>此方法仅支持一个db上下文，如果多次调用，将抛出异常。</remarks>
/// <returns></returns>
public static IServiceCollection AddUnitOfWorkService<TContext>(this IServiceCollection services, System.Action<DbContextOptionsBuilder> action) where TContext : DbContext
{
//注册dbcontext
services.AddDbContext<TContext>(action);
//注册工作单元
services.AddScoped<IUnitOfWork<TContext>, UnitOfWork<TContext>>();
return services;
}
}
}
这样一来，如果项目要使用该工作单元，直接在Startup中调用AddUnitOfWorkService注册即可
项目完成后，如下图所示：
使用方法展示
using (var tran = _unitOfWork.BeginTransaction())//开启一个事务
{
Role newRow = _mapper.Map<Role>(viewModel);
newRow.Id = _idWorker.NextId();//获取一个雪花Id
newRow.Creator = 1219490056771866624;//由于暂时还没有做登录，所以拿不到登录者信息，先随便写一个后面再完善
newRow.CreateTime = DateTime.Now;
_unitOfWork.GetRepository<Role>().Insert(newRow);
await _unitOfWork.SaveChangesAsync();
await tran.CommitAsync();//提交事务
}
以上展示了工作单元开启事务，用using包裹，直到tran.CommitAsync()才提交事务，如果遇到错误，会自动回滚
//从数据库中取出该记录
var row = await _unitOfWork.GetRepository<Role>().FindAsync(viewModel.Id);//在viewModel.CheckField中已经获取了一次用于检查，所以此处不会重复再从数据库取一次，有缓存
//修改对应的值
row.Name = viewModel.Name;
row.DisplayName = viewModel.DisplayName;
row.Remark = viewModel.Remark;
row.Modifier = 1219490056771866624;//由于暂时还没有做登录，所以拿不到登录者信息，先随便写一个后面再完善
row.ModifyTime = DateTime.Now;
_unitOfWork.GetRepository<Role>().Update(row);
await _unitOfWork.SaveChangesAsync();//提交
- 以上展示了根据主键Id获取数据，更新数据。
- 也可以GetFirstOrDefault获取数据，disableTracking参数设为false，开启追踪，这样获取到的数据修改后，直接SaveChangesAsync，不需要update（关键就是开启了追踪，所以不需要update实体了）
