浅谈WPF之DataGrid动态生成列

在日常开发中,DataGrid作为二维表格,非常适合数据的展示和统计。通常情况下,一般都有固定的格式和确定的数据列展示,但是在某些特殊情况下,也可能会需要用到动态生成列。本文以一些简单的小例子,简述在WPF开发中,如何动态生成DataGrid的行和列,仅供学习分享使用,如有不足之处,还请指正。

 

涉及知识点

 

在本示例中,用到的知识点如下所示:

  1. CommunityToolkit.Mvvm,微软提供的一个基于.Net的MVVM框架库,通过此库,可以方便是实现数据绑定和命令绑定,达到前后端分离的目的。
  2. ObservableCollection ,相比较于List,当列表中的数据条数发生变化时,会自动进行通知,实现数据的实时更新。
  3. DataTable,表示内存的一个数据表格,可以动态创建列,并自动绑定到DataGrid中。
  4. ExpandoObject 表示一个动态对象,其内容可以动态添加和删除。

 

普通绑定

 

将ViewModel中的列表对象,绑定到View页面中的DataGrid,实现步骤如下:

 

1. 创建模型

 

创建绑定到DataGrid中的对象模型,如下所示:

public class Student
{
	/// <summary>
	/// 唯一标识
	/// </summary>
	public int Id { get; set; } 

	/// <summary>
	/// 姓名
	/// </summary>
	public string Name { get; set; }

	/// <summary>
	/// 年龄
	/// </summary>
	public int Age { get; set; }

	/// <summary>
	/// 性别
	/// </summary>
	public string Gender { get; set; }

	/// <summary>
	/// 地址
	/// </summary>
	public string Addr { get; set; }
}

 

2. 创建数据源列表对象

 

创建要绑定到视图层的列表对象Students,并赋值,如下所示:

public class GeneralBindingViewModel:ObservableObject
{
	private ObservableCollection<Student> students;

	public ObservableCollection<Student> Students
	{
		get { return students; }
		set { SetProperty(ref students, value); }
	}

	public GeneralBindingViewModel()
	{
		Students=new ObservableCollection<Student>();
	}

	#region Loaded命令

	private ICommand winLoadedCommand;

	public ICommand WinLoadedCommand
	{
		get
		{
			if (winLoadedCommand == null)
			{
				winLoadedCommand = new RelayCommand<object>(WinLoaded);
			}
			return winLoadedCommand;
		}
	}

	private void WinLoaded(object sender)
	{
		if (sender != null)
		{

		}
		if (Students == null || Students.Count < 1)
		{
			var parentName = new string[5] { "张", "王", "李", "赵", "刘" };
			var province = new string[5] { "河南", "江苏", "河北", "湖北", "福建" };
			for (int i = 0; i < 20; i++)
			{
				var student = new Student()
				{
					Id = i,
					Name = parentName[(i % 4)] + i.ToString().PadLeft(2, 'A'),
					Age = 20 + (i % 5),
					Gender = i % 2 == 0 ? "男" : "女",
					Addr = province[(i % 4)]
				};
				this.Students.Add(student);
			}
		}
	}

	#endregion
}

 

3. 视图绑定

 

在UI视图中,为DataGrid的ItemsSource属性绑定数据源,如下所示:

<Window x:Class="DemoDynamicBinding.GeneralBinding"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:i="http://schemas.microsoft.com/xaml/behaviors"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:DemoDynamicBinding"
        mc:Ignorable="d"
        Title="基础绑定" Height="450" Width="800">
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="Loaded">
            <i:InvokeCommandAction Command="{Binding WinLoadedCommand}" CommandParameter="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}}"/>
        </i:EventTrigger>
    </i:Interaction.Triggers>
    <Grid>
        <DataGrid ItemsSource="{Binding Students}" CanUserAddRows="False" CanUserDeleteRows="False" ColumnWidth="*" ColumnHeaderHeight="30" RowHeight="25" AlternationCount="2" AlternatingRowBackground="AliceBlue" RowBackground="#ffffee">
            
        </DataGrid>
    </Grid>
</Window>

 

4. 关联视图层和ViewModel层

 

在视图文件对应的cs文件中,创建ViewModel对象,如下所示:

public partial class GeneralBinding : Window
{
	private GeneralBindingViewModel viewModel;

	public GeneralBinding()
	{
		InitializeComponent();
		if(viewModel == null)
		{
			viewModel = new GeneralBindingViewModel();
			this.DataContext = viewModel;
		}
	}
}

 

动态生成列

 

在WPF开发中,动态生成DataGrid列,共有两种方式:

 

1. DataTable作为数据源

 

通过DataTable作为数据源,可以不用创建模型,也不需要使用ObservableCollection对象,直接使用DataTable作为数据承载对象,DataGrid会根据DataTable的Columns列表自动生成列。如下所示:

public class DataTableBindingViewModel:ObservableObject
{
	private DataTable students;

	public DataTable Students
	{
		get { return students; }
		set { SetProperty(ref students , value); }
	}

	public DataTableBindingViewModel()
	{
		Students = new DataTable();
	}

	#region Loaded命令

	private ICommand winLoadedCommand;

	public ICommand WinLoadedCommand
	{
		get
		{
			if (winLoadedCommand == null)
			{
				winLoadedCommand = new RelayCommand<object>(WinLoaded);
			}
			return winLoadedCommand;
		}
	}

	private void WinLoaded(object sender)
	{
		if (sender != null)
		{

		}
		if (Students == null || Students.Rows.Count < 1)
		{
			var students = new DataTable();
			students.Columns.Add("Id",typeof(int));
			students.Columns.Add("Name", typeof(string));
			students.Columns.Add("Age", typeof(int));
			students.Columns.Add("Gender", typeof(string));
			students.Columns.Add("Addr", typeof(string));
			var parentName = new string[5] { "张", "王", "李", "赵", "刘" };
			var province = new string[5] { "河南", "江苏", "河北", "湖北", "福建" };
			
			for (int i = 0; i < 20; i++)
			{
				var dr = students.NewRow();
				dr["Id"] = i;
				dr["Name"] = parentName[(i % 5)] + i.ToString().PadLeft(2, 'A');
				dr["Age"] = 20 + (i % 5);
				dr["Gender"] = i % 2 == 0 ? "男" : "女";
				dr["Addr"] = province[(i % 5)];
			   
				students.Rows.Add(dr);
			}
			this.Students= students;
		}
	}

	#endregion

}

 

2. ExpandoObject作为模型

 

ExpandoObject是dynamic类型,可以在运行时动态的添加和删除内容。而且ExpandoObject对象支持Key=Value形式,并可以对Key进行绑定。如下所示:

public class DynamicBindingViewModel : ObservableObject
{
	private ObservableCollection<ExpandoObject> students;

	public ObservableCollection<ExpandoObject> Students
	{
		get { return students; }
		set { SetProperty(ref students , value); }
	}

	private DataGrid dataGrid;


	public DynamicBindingViewModel()
	{
		this.Students = new ObservableCollection<ExpandoObject>();
	}

	#region Loaded命令

	private ICommand winLoadedCommand;

	public ICommand WinLoadedCommand
	{
		get
		{
			if (winLoadedCommand == null)
			{
				winLoadedCommand = new RelayCommand<object>(WinLoaded);
			}
			return winLoadedCommand;
		}
	}

	private void WinLoaded(object sender)
	{
		if (sender != null)
		{
			var control = sender as DynamicBinding;
			if (control != null)
			{
				this.dataGrid = control.dgTest;
			}
		}
		if (Students == null || Students.Count < 1)
		{
			var parentName = new string[5] { "张", "王", "李", "赵", "刘" };
			var province = new string[5] { "河南", "江苏", "河北", "湖北", "福建" };
			for (int i = 0; i < 20; i++)
			{
				dynamic item = new ExpandoObject();
				item.Id=i.ToString();
				item.Name = parentName[(i % 5)] + i.ToString().PadLeft(2, 'A');
				item.Age = 20 + (i % 5);
				item.Gender = i % 2 == 0 ? "男" : "女";
				item.Addr = province[(i % 5)];
				this.Students.Add(item);
			}
			//添加列
			this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "学号", Binding = new Binding("Id") });
			this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "姓名", Binding = new Binding("Name") });
			this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "年龄", Binding = new Binding("Age") });
			this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "性别", Binding = new Binding("Gender") });
			this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "地址", Binding = new Binding("Addr") });
		}
	}

	#endregion
}

 

示例效果

 

以上三种方式,实现的效果都是一致的,只是分别应用到不同的场景中,如下所示:

 

源码下载

 

关于源码下载,可关注公众号,回复关键字:WDDGRID 即可,如下所示:

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posted @ 2024-02-22 23:30  老码识途呀  阅读(920)  评论(1编辑  收藏  举报