淺談WPF之DataGrid動態生成列

在日常開發中,DataGrid作爲二維表格,非常適合數據的展示和統計。通常情況下,一般都有固定的格式和確定的數據列展示,但是在某些特殊情況下,也可能會需要用到動態生成列。本文以一些簡單的小例子,簡述在WPF開發中,如何動態生成DataGrid的行和列,僅供學習分享使用,如有不足之處,還請指正。

 

涉及知識點

 

在本示例中,用到的知識點如下所示:

  1. CommunityToolkit.Mvvm,微軟提供的一個基於.Net的MVVM框架庫,通過此庫,可以方便是實現數據綁定和命令綁定,達到前後端分離的目的。
  2. ObservableCollection ,相比較於List,當列表中的數據條數發生變化時,會自動進行通知,實現數據的實時更新。
  3. DataTable,表示內存的一個數據表格,可以動態創建列,並自動綁定到DataGrid中。
  4. ExpandoObject 表示一個動態對象,其內容可以動態添加和刪除。

 

普通綁定

 

將ViewModel中的列表對象,綁定到View頁面中的DataGrid,實現步驟如下:

 

1. 創建模型

 

創建綁定到DataGrid中的對象模型,如下所示:

public class Student
{
	/// <summary>
	/// 唯一標識
	/// </summary>
	public int Id { get; set; } 

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

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

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

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

 

2. 創建數據源列表對象

 

創建要綁定到視圖層的列表對象Students,並賦值,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] { "張", "王", "李", "趙", "劉" };
			var province = new string[5] { "河南", "江蘇", "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. 視圖綁定

 

在UI視圖中,爲DataGrid的ItemsSource屬性綁定數據源,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="基礎綁定" 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. 關聯視圖層和ViewModel層

 

在視圖文件對應的cs文件中,創建ViewModel對象,如下所示:

public partial class GeneralBinding : Window
{
	private GeneralBindingViewModel viewModel;

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

 

動態生成列

 

在WPF開發中,動態生成DataGrid列,共有兩種方式:

 

1. DataTable作爲數據源

 

通過DataTable作爲數據源,可以不用創建模型,也不需要使用ObservableCollection對象,直接使用DataTable作爲數據承載對象,DataGrid會根據DataTable的Columns列表自動生成列。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] { "張", "王", "李", "趙", "劉" };
			var province = new string[5] { "河南", "江蘇", "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作爲模型

 

ExpandoObject是dynamic類型,可以在運行時動態的添加和刪除內容。而且ExpandoObject對象支持Key=Value形式,並可以對Key進行綁定。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] { "張", "王", "李", "趙", "劉" };
			var province = new string[5] { "河南", "江蘇", "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 = "學號", Binding = new Binding("Id") });
			this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "姓名", Binding = new Binding("Name") });
			this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "年齡", Binding = new Binding("Age") });
			this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "性別", Binding = new Binding("Gender") });
			this.dataGrid.Columns.Add(new DataGridTextColumn() { Header = "地址", Binding = new Binding("Addr") });
		}
	}

	#endregion
}

 

示例效果

 

以上三種方式,實現的效果都是一致的,只是分別應用到不同的場景中,如下所示:

 

源碼下載

 

關於源碼下載,可關注公衆號,回覆關鍵字:WDDGRID 即可,如下所示:

以上就是【淺談WPF之DataGrid動態生成列】的全部內容,關於更多詳細內容,可參考官方文檔。希望能夠一起學習,共同進步。

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