浅谈WPF之DataGrid动态生成列

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摘要

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。

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。

浅谈WPF之DataGrid动态生成列

 

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:

浅谈WPF之DataGrid动态生成列

 

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:

浅谈WPF之DataGrid动态生成列

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