WPF Toolkit DataGrid Multi-Select：如何获取SelectedItems？ [英] WPF Toolkit DataGrid Multi-Select: How to get SelectedItems out?

问题描述

我正在使用WPF Toolkit的DataGrid。我启用DataGrid上的属性允许多行选择。如何获取SelectedItems？我使用MVVM框架将ViewModel绑定到我的View。

谢谢！

解决方案

采取比尔的答案，合并选项1和2，添加一个附加的属性的喷洒作为编写代码隐藏的替代品，我想出了一个行为。

首先，我们有以下行为：

 公共类SelectedItemsBehavior 
 
公共共享ReadOnly SelectedItemsChangedHandlerProperty作为DependencyProperty = 
 DependencyProperty.RegisterAttached（SelectedItemsChangedHandler，
 GetType（mvvm.RelayCommand），GetType（SelectedItemsBehavior），
 New FrameworkPropertyMetadata PropertyChangedCallback（AddressOf OnSelectedItemsChangedHandlerChanged）））
 
 
 
 
公共共享函数GetSelectedItemsChangedHandler（ByVal元素为DependencyObject）为mvvm.RelayCommand 
如果元素为Nothing Then抛出新的ArgumentNullException（element）
返回element.GetValue（SelectedItemsChangedHandlerProperty）
结束函数
 
公共共享子集SetSelectedItemsChangedHandler（ByVal元素为DependencyObject，ByVal值为mvvm.RelayCommand） 
如果元素是Nothing然后抛出新的Arg umentNullException（element）
 element.SetValue（SelectedItemsChangedHandlerProperty，value）
 End Sub 
 
 Private Shared Sub OnSelectedItemsChangedHandlerChanged（d As DependencyObject，$ b $ as As DependencyPropertyChangedEventArgs）
 
 Dim dataGrid As DataGrid = DirectCast（d，DataGrid）
 
如果e.OldValue不是，还有e.NewValue IsNot Nothing然后
 AddHandler dataGrid.SelectionChanged，AddressOf ItemsControl_SelectionChanged 
 End If 
 
如果e.OldValue IsNot Nothing AndAlso e.NewValue Is Nothing Then 
 RemoveHandler dataGrid.SelectionChanged，AddressOf ItemsControl_SelectionChanged 
 End If 
 
 End Sub 
 
 
公共共享子项目Control_SelectionChanged（发件人作为对象，$ b $作为SelectionChangedEventArgs）
 
 Dim DataGrid As DataGrid = DirectCast（sender，DataGrid）
 
 Dim itemsChangedHandler As RelayCommand = GetSelectedItemsChangedHandler（dataGrid）
 
 itemsChangedHandler.Execute（dataGrid.SelectedItems）
 
 End Sub 
 
结束类
  

C＃：

 使用Microsoft.VisualBasic; 
使用系统; 
使用System.Collections; 
使用System.Collections.Generic; 
使用System.Data; 
使用System.Diagnostics; 
 public class SelectedItemsBehavior 
 {
 
 
 public static readonly DependencyProperty SelectedItemsChangedHandlerProperty = DependencyProperty.RegisterAttached（SelectedItemsChangedHandler，typeof（mvvm.RelayCommand），typeof（SelectedItemsBehavior）新的FrameworkPropertyMetadata（新的PropertyChangedCallback（OnSelectedItemsChangedHandlerChanged）））; 
 
 
 
 public static mvvm.RelayCommand GetSelectedItemsChangedHandler（DependencyObject element）
 {
 if（element == null）
 throw new ArgumentNullException 元件）; 
 return element.GetValue（SelectedItemsChangedHandlerProperty）; 
} 
 
 public static void SetSelectedItemsChangedHandler（DependencyObject element，mvvm.RelayCommand value）
 {
 if（element == null）
 throw new ArgumentNullException 元件）; 
 element.SetValue（SelectedItemsChangedHandlerProperty，value）; 
} 
 
 
 private static void OnSelectedItemsChangedHandlerChanged（DependencyObject d，DependencyPropertyChangedEventArgs e）
 {
 DataGrid dataGrid =（DataGrid）d; 
 
 if（e.OldValue == null&& e.NewValue！= null）{
 dataGrid.SelectionChanged + = ItemsControl_SelectionChanged; 
} 
 
 if（e.OldValue！= null&& e.NewValue == null）{
 dataGrid.SelectionChanged  -  = ItemsControl_SelectionChanged; 
} 
 
} 
 
 
 
 public static void ItemsControl_SelectionChanged（object sender，SelectionChangedEventArgs e）
 {
 DataGrid dataGrid =（DataGrid）发件人; 
 
 RelayCommand itemsChangedHandler = GetSelectedItemsChangedHandler（dataGrid）; 
 
 itemsChangedHandler.Execute（dataGrid.SelectedItems）; 
 
} 
 
} 
  

然后我们添加它到XAML中的datagrid：

 < DataGrid AutoGenerateColumns =FalseFontFamily =TahomaFontSize =9
 ItemsSource ={Binding Path = ResultsVM}
 mvvm：SelectedItemsBehavior.SelectedItemsChangedHandler ={Binding Path = ResultsSelectionChangedCommand}/> 
  

然后我们在ViewModel中编写RelayCommand：

公开ReadOnly属性ResultsSelectionChangedCommand（）作为mvvm.RelayCommand
获取
如果_resultsSelectionChangedCommand是Nothing然后
_resultsSelectionChangedCommand =新的mvvm.RelayCommand（AddressOf ResultsSelectionChanged）
结束如果
返回_resultsSelectionChangedCommand
结束获取
结束属性

公共子结果选择改变（ByVal selectedItems As Object）

_resultsSelectedItems .Clear（）
对于每个项目在selectedItems
_resultsSelectedItems.Add（item）
下一个

End Sub
/ pre>

C＃：

  public mvvm.RelayCommand ResultsSelectionChangedCommand {
 get {
 if（_resultsSelectionChangedCommand == null）{
 _resultsS electionChangedCommand = new mvvm.RelayCommand（ResultSelectionChanged）; 
} 
 return _resultsSelectionChangedCommand; 
} 
} 
 
 
 public void ResultsSelectionChanged（object selectedItems）
 {
 _resultsSelectedItems.Clear（）; 
 foreach（items in selectedItems）{
 _resultsSelectedItems.Add（item）; 
} 
 
} 
  

_resultsSelectedItems只是一个DataGrid中显示的项目：

 私有_resultsSelectedItems作为新列表（WorkOrderMatchViewModel）
  

C＃：

 私人列表< WorkOrderMatchViewModel> _resultsSelectedItems = new List< WorkOrderMatchViewModel>（）; 
  

希望这有助于使用比尔的两种方法，而无需引用MVVM-Light。

I'm using the WPF Toolkit's DataGrid. I've enabled the property on the DataGrid to allow for multi-selecting of rows. How do I get the SelectedItems out? I'm using an MVVM framework to bind my ViewModel to my View.

Thanks!

解决方案

Taking Bill's answer, merging options 1 and 2, adding a sprinkling of attached properties as an alternative to writing code-behind, I came up with a Behavior.

Firstly, we have the behavior:

Public Class SelectedItemsBehavior

    Public Shared ReadOnly SelectedItemsChangedHandlerProperty As DependencyProperty =
        DependencyProperty.RegisterAttached("SelectedItemsChangedHandler",
            GetType(mvvm.RelayCommand), GetType(SelectedItemsBehavior),
            New FrameworkPropertyMetadata(New PropertyChangedCallback(AddressOf OnSelectedItemsChangedHandlerChanged)))




    Public Shared Function GetSelectedItemsChangedHandler(ByVal element As DependencyObject) As mvvm.RelayCommand
        If element Is Nothing Then Throw New ArgumentNullException("element")
        Return element.GetValue(SelectedItemsChangedHandlerProperty)
    End Function

    Public Shared Sub SetSelectedItemsChangedHandler(ByVal element As DependencyObject, ByVal value As mvvm.RelayCommand)
        If element Is Nothing Then Throw New ArgumentNullException("element")
        element.SetValue(SelectedItemsChangedHandlerProperty, value)
    End Sub

    Private Shared Sub OnSelectedItemsChangedHandlerChanged(d As DependencyObject,
                                                            e As DependencyPropertyChangedEventArgs)

        Dim dataGrid As DataGrid = DirectCast(d, DataGrid)

        If e.OldValue Is Nothing AndAlso e.NewValue IsNot Nothing Then
            AddHandler dataGrid.SelectionChanged, AddressOf ItemsControl_SelectionChanged
        End If

        If e.OldValue IsNot Nothing AndAlso e.NewValue Is Nothing Then
            RemoveHandler dataGrid.SelectionChanged, AddressOf ItemsControl_SelectionChanged
        End If

    End Sub


    Public Shared Sub ItemsControl_SelectionChanged(sender As Object,
                                                    e As SelectionChangedEventArgs)

        Dim dataGrid As DataGrid = DirectCast(sender, DataGrid)

        Dim itemsChangedHandler As RelayCommand = GetSelectedItemsChangedHandler(dataGrid)

        itemsChangedHandler.Execute(dataGrid.SelectedItems)

    End Sub

End Class

C#:

using Microsoft.VisualBasic;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
public class SelectedItemsBehavior
{


    public static readonly DependencyProperty SelectedItemsChangedHandlerProperty = DependencyProperty.RegisterAttached("SelectedItemsChangedHandler", typeof(mvvm.RelayCommand), typeof(SelectedItemsBehavior), new FrameworkPropertyMetadata(new PropertyChangedCallback(OnSelectedItemsChangedHandlerChanged)));



    public static mvvm.RelayCommand GetSelectedItemsChangedHandler(DependencyObject element)
    {
        if (element == null)
            throw new ArgumentNullException("element");
        return element.GetValue(SelectedItemsChangedHandlerProperty);
    }

    public static void SetSelectedItemsChangedHandler(DependencyObject element, mvvm.RelayCommand value)
    {
        if (element == null)
            throw new ArgumentNullException("element");
        element.SetValue(SelectedItemsChangedHandlerProperty, value);
    }


    private static void OnSelectedItemsChangedHandlerChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        DataGrid dataGrid = (DataGrid)d;

        if (e.OldValue == null && e.NewValue != null) {
            dataGrid.SelectionChanged += ItemsControl_SelectionChanged;
        }

        if (e.OldValue != null && e.NewValue == null) {
            dataGrid.SelectionChanged -= ItemsControl_SelectionChanged;
        }

    }



    public static void ItemsControl_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        DataGrid dataGrid = (DataGrid)sender;

        RelayCommand itemsChangedHandler = GetSelectedItemsChangedHandler(dataGrid);

        itemsChangedHandler.Execute(dataGrid.SelectedItems);

    }

}

Then we add it to the datagrid in XAML:

<DataGrid AutoGenerateColumns="False" FontFamily="Tahoma" FontSize="9"
          ItemsSource="{Binding Path=ResultsVM}" 
          mvvm:SelectedItemsBehavior.SelectedItemsChangedHandler="{Binding Path=ResultsSelectionChangedCommand}" />

Then we code the RelayCommand in the ViewModel:

    Public ReadOnly Property ResultsSelectionChangedCommand() As mvvm.RelayCommand
        Get
            If _resultsSelectionChangedCommand Is Nothing Then
                _resultsSelectionChangedCommand = New mvvm.RelayCommand(AddressOf ResultsSelectionChanged)
            End If
            Return _resultsSelectionChangedCommand
        End Get
    End Property

    Public Sub ResultsSelectionChanged(ByVal selectedItems As Object)

        _resultsSelectedItems.Clear()
        For Each item In selectedItems
            _resultsSelectedItems.Add(item)
        Next

    End Sub

C#:

public mvvm.RelayCommand ResultsSelectionChangedCommand {
    get {
        if (_resultsSelectionChangedCommand == null) {
            _resultsSelectionChangedCommand = new mvvm.RelayCommand(ResultsSelectionChanged);
        }
        return _resultsSelectionChangedCommand;
    }
}


public void ResultsSelectionChanged(object selectedItems)
{
    _resultsSelectedItems.Clear();
    foreach (item in selectedItems) {
        _resultsSelectedItems.Add(item);
    }

}

The _resultsSelectedItems is simply a list of items displayed in the DataGrid:

    Private _resultsSelectedItems As New List(Of WorkOrderMatchViewModel)

C#:

private List<WorkOrderMatchViewModel> _resultsSelectedItems = new List<WorkOrderMatchViewModel>();

Hope this helps, kinda uses both of Bill's methods without having to reference MVVM-Light.

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