温故知新ASP.NET 2.0(C#)(8) - DataSourceControl(数据源控件)

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温故知新ASP.NET 2.0(C#)(8) - DataSourceControl(数据源控件)


作者:webabcd


介绍
在 ASP.NET 2.0 中有几个新的数据源控件,例如,SqlDataSource、ObjectDataSource、XmlDataSource、AccessDataSource 和 SiteMapDataSource。它们全都可以用来从它们各自类型的数据源中检索数据,并且可以绑定到各种数据绑定控件。数据源控件减少了为检索和绑定数据甚至对数据进行排序、分页或编辑而需要编写的自定义代码的数量。

其中 ObjectDataSource 控件可针对各种基础数据存储区(如 SQL 数据库或 XML)启用声明性数据绑定模型。因为页开发人员也常常将数据检索(也可能包含业务逻辑)封装在一个组件对象中,从而在呈现页和数据提供程序之间引入另一个层。ObjectDataSource 控件允许开发人员使用此传统的三层结构构造应用程序,同时仍然能够利用 ASP.NET 中的声明性数据绑定模型的易用性优点。


关键
1、在数据层创建 强类型的DataSet和TableAdapter,TableAdapter查询可以使用现有的存储过程。注:直接把表或存储过程拖进来会自动创建TableAdapter

2、中间层的类用[System.ComponentModel.DataObject]声明为数据组件,CRUD方法分别对应[DataObjectMethod(DataObjectMethodType.Insert)],[DataObjectMethod(DataObjectMethodType.Select)],[DataObjectMethod(DataObjectMethodType.Update)],[DataObjectMethod(DataObjectMethodType.Delete)]

3、web层使用ObjectDataSource展现数据,ObjectDataSource就相当于一个代理。ObjectDataSource只是查找具有匹配的参数名称的方法,它不会使用参数的 Type 或 Size,而只是对参数的名称进行匹配

4、其它
  ·<asp:Parameter />有ConvertEmptyStringToNull属性,默认是true。另外还有Direction属性
  ·注意<asp:BoundField />的这几个属性NullDisplayText,HtmlEncode,ApplyFormatInEditMode,InsertVisible,DataFormatString,ReadOnly
  ·DataKeyNames有多个值的话用“,”分隔,用<asp:ControlParameter />绑定的话给其加一个“PropertyName”属性,值类似如下“SelectedDataKey.Values[0]”
  ·关于绑定:简单属性<%# custID %>;集合<asp:ListBox id="List1" datasource='<%# myArray %>' runat="server">;表达式<%# ( customer.FirstName + " " + customer.LastName ) %>;方法<%# GetBalance(custID) %> 
  ·<%# Eval("field1") %> 和 <%# Bind("field1") %>,Eval是单向绑定,Bind是双向邦定
  ·<asp:ObjectDataSource />有一个OldValuesParameterFormatString属性一般不用,不过如果要处理乐观并发之类的就会用到。当该属性的值为“original_{0}”的时候“original_参数名”则为初始值
  ·还有一些如编程方式给参数赋值,错误处理,得到返回值之类的请看源码


示例
相关存储过程和数据层略,见源码

单例模式的实现
App_Code/Singleton.cs
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

/// <summary>
/// Singleton 的摘要说明
/// </summary>

public class Singleton<T> where T : new()
{
    
public static T Instance
    
{
        
get return SingletonCreator.instance; }
    }


    
class SingletonCreator
    
{
        
internal static readonly T instance = new T();
    }

}


中间层代码
App_Code/Test.cs
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

using TestDatabaseTableAdapters;
using System.ComponentModel;

/// <summary>
/// Test 的摘要说明
/// </summary>

[DataObject]
public class Test
{
    [DataObjectMethod(DataObjectMethodType.Select, 
true)]
    
public TestDatabase.TestDataTable GetTest()
    
{
        
return Singleton<TestTableAdapter>.Instance.GetTest();
    }


    [DataObjectMethod(DataObjectMethodType.Select, 
false)]
    
public TestDatabase.TestDataTable GetTestById(int id)
    
{
        
return Singleton<TestTableAdapter>.Instance.GetTestById(id);
    }


    [DataObjectMethod(DataObjectMethodType.Insert, 
true)]
    
public int?[] InsertTest(int? parentId, string name, DateTime? publishTime, decimal? price, bool? isGood, out int? minId)
    
{
        
// 仅为说明如何做错误处理
        if (String.IsNullOrEmpty(name))
            
throw new ArgumentException("参数不能是空""name");

        
int? id = null;
        
int? count = null;
        minId 
= null;

        Singleton
<TestTableAdapter>.Instance.InsertTest(parentId, name, publishTime, price, isGood, ref id, ref count, ref minId);
        
return new int?[] { id, count };
    }


    [DataObjectMethod(DataObjectMethodType.Delete, 
true)]
    
public int? DeleteTest(int id)
    
{
        
int? rowAffected;

        rowAffected 
= Singleton<TestTableAdapter>.Instance.DeleteTest(id);
        
return rowAffected;
    }


    [DataObjectMethod(DataObjectMethodType.Update, 
true)]
    
public int? UpdateTest(int? id, int? parentId, string name, DateTime? publishTime, decimal? price, bool? isGood)
    
{
        
int? rowAffected;

        rowAffected 
= Singleton<TestTableAdapter>.Instance.UpdateTest(id, parentId, name, publishTime, price, isGood);
        
return rowAffected;
    }

}


DataSourceControl/Test.aspx
<%@ Page Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="Test.aspx.cs"
    Inherits
="DataSourceControl_Test" Title="数据源控件测试" 
%>

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
    
<p>
        
<asp:Label ID="lblMsg" runat="server" ForeColor="red" />
    
</p>
    
<table cellpadding="6">
        
<tr>
            
<td valign="top">
                
<asp:DetailsView ID="DetailsView1" runat="server" AllowPaging="True" AutoGenerateRows="False"
                    DataKeyNames
="Id" DataSourceID="ObjectDataSource1" Height="50px" Width="125px" OnItemInserted="DetailsView1_ItemInserted">
                    
<Fields>
                        
<asp:BoundField DataField="Id" HeaderText="Id" InsertVisible="False" ReadOnly="True"
                            SortExpression
="Id" />
                        
<asp:BoundField DataField="ParentId" HeaderText="ParentId" SortExpression="ParentId" />
                        
<asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                        
<asp:BoundField DataField="PublishTime" HeaderText="PublishTime" SortExpression="PublishTime"
                            InsertVisible
="False" />
                        
<asp:BoundField DataField="Price" HeaderText="Price" SortExpression="Price" DataFormatString="{0:c}" HtmlEncode="False" />
                        
<asp:CheckBoxField DataField="IsGood" HeaderText="IsGood" SortExpression="IsGood" />
                        
<asp:CommandField ShowInsertButton="True" />
                    
</Fields>
                
</asp:DetailsView>
            
</td>
            
<td valign="top">
                
<asp:DetailsView ID="DetailsView2" runat="server" Height="50px" Width="125px" AutoGenerateRows="False" DataKeyNames="Id" DataSourceID="ObjectDataSource2">
                    
<Fields>
                        
<asp:BoundField DataField="Id" HeaderText="Id" InsertVisible="False" ReadOnly="True"
                            SortExpression
="Id" />
                        
<asp:BoundField DataField="ParentId" HeaderText="ParentId" SortExpression="ParentId" />
                        
<asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                        
<asp:BoundField DataField="PublishTime" HeaderText="PublishTime" SortExpression="PublishTime" />
                        
<asp:BoundField DataField="Price" HeaderText="Price" SortExpression="Price" DataFormatString="{0:c}" HtmlEncode="false" />
                        
<asp:CheckBoxField DataField="IsGood" HeaderText="IsGood" SortExpression="IsGood" />
                    
</Fields>
                
</asp:DetailsView>
            
</td>
        
</tr>
    
</table>
    
<p>
        
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="Id"
            DataSourceID
="ObjectDataSource1" AllowPaging="True" AllowSorting="True" OnRowUpdating="GridView1_RowUpdating">
            
<Columns>
                
<asp:CommandField ShowDeleteButton="True" ShowEditButton="True" ShowSelectButton="True" />
                
<asp:BoundField DataField="Id" HeaderText="Id" InsertVisible="False" ReadOnly="True"
                    SortExpression
="Id" />
                
<asp:BoundField DataField="ParentId" HeaderText="ParentId" SortExpression="ParentId"
                    NullDisplayText
="我的值是NULL" />
                
<asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                
<asp:BoundField DataField="PublishTime" HeaderText="PublishTime" SortExpression="PublishTime"
                    ReadOnly
="true" />
                
<asp:BoundField DataField="Price" HeaderText="Price" SortExpression="Price" DataFormatString="{0:c}" HtmlEncode="false" ApplyFormatInEditMode="True" />
                
<asp:CheckBoxField DataField="IsGood" HeaderText="IsGood" SortExpression="IsGood" />
            
</Columns>
        
</asp:GridView>
    
</p>
    
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server" SelectMethod="GetTest"
        TypeName
="Test" InsertMethod="InsertTest" DeleteMethod="DeleteTest" UpdateMethod="UpdateTest"
        OnInserting
="ObjectDataSource1_Inserting" OnInserted="ObjectDataSource1_Inserted">
        
<InsertParameters>
            
<%--ConvertEmptyStringToNull属性默认为true--%>
            
<asp:Parameter Name="parentId" Type="Int32" ConvertEmptyStringToNull="true" />
            
<asp:Parameter Name="name" Type="String" />
            
<asp:Parameter Name="publishTime" Type="DateTime" />
            
<asp:Parameter Name="price" Type="Decimal" />
            
<asp:Parameter Name="isGood" Type="Boolean" />
            
<asp:Parameter Direction="Output" Name="minId" Type="Int32" />
        
</InsertParameters>
        
<DeleteParameters>
            
<asp:Parameter Name="id" Type="Int32" />
        
</DeleteParameters>
        
<UpdateParameters>
            
<asp:Parameter Name="id" Type="Int32" />
            
<asp:Parameter Name="parentId" Type="Int32" />
            
<asp:Parameter Name="name" Type="String" />
            
<asp:Parameter Name="publishTime" Type="DateTime" />
            
<asp:Parameter Name="price" Type="Decimal" />
            
<asp:Parameter Name="isGood" Type="Boolean" />
        
</UpdateParameters>
    
</asp:ObjectDataSource>
    
<asp:ObjectDataSource ID="ObjectDataSource2" runat="server" OldValuesParameterFormatString="original_{0}"
        SelectMethod
="GetTestById" TypeName="Test">
        
<SelectParameters>
            
<asp:ControlParameter ControlID="GridView1" Name="id" PropertyName="SelectedValue"
                Type
="Int32" />
        
</SelectParameters>
    
</asp:ObjectDataSource>
</asp:Content>

DataSourceControl/Test.aspx.cs
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class DataSourceControl_Test : System.Web.UI.Page
{
    
protected void Page_Load(object sender, EventArgs e)
    
{

    }


    
protected void ObjectDataSource1_Inserting(object sender, ObjectDataSourceMethodEventArgs e)
    
{
        
// 编程方式给参数赋值
        if (e.InputParameters["publishTime"== null)
        
{
            e.InputParameters[
"publishTime"= DateTime.Now;
        }

    }


    
protected void ObjectDataSource1_Inserted(object sender, ObjectDataSourceStatusEventArgs e)
    
{
        
// 错误处理
        if (e.Exception != null)
        
{
            
if (e.Exception.InnerException != null)
            
{
                Exception inner 
= e.Exception.InnerException;

                
if (inner is ArgumentException)
                
{
                    
string paramName = ((ArgumentException)inner).ParamName;
                    lblMsg.Text 
= string.Concat("参数 ", paramName, " 有问题");
                }

            }

        }

        
else
        
{
            
int?[] ary = (int?[])e.ReturnValue;
            lblMsg.Text 
= "新插入信息的ID是:" + ary[0].ToString();
            lblMsg.Text 
+= "<br />数据总数是:" + ary[1].ToString();

            lblMsg.Text 
+= "<br />最小ID是:" + e.OutputParameters["minId"].ToString();
        }

    }


    
protected void DetailsView1_ItemInserted(object sender, DetailsViewInsertedEventArgs e)
    
{
        
if (e.Exception != null)
        
{
            
// 错误已处理
            e.ExceptionHandled = true;
            
// DetailsView保持插入状态
            e.KeepInInsertMode = true;
        }

    }


    
protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    
{
        
// 价格格式转换为decimal格式
        if (e.NewValues["Price"!= null)
            e.NewValues[
"Price"= decimal.Parse(e.NewValues["Price"].ToString(), System.Globalization.NumberStyles.Currency);
    }

}



OK
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posted @ 2007-02-23 21:21  webabcd  阅读(9242)  评论(12编辑  收藏  举报