WPF DataGrid多重选择绑定 [英] WPF DataGrid multiselect binding

问题描述

我有一个datagrid是多选择启用。我需要更改视图模型中的选择。但是，SelectedItems属性是只读的，不能直接绑定到viewmodel中的属性。那么我如何表示选择已经改变了？

解决方案

Andy是正确的。 DataGridRow.IsSelected 是一个依赖属性，可以通过数据绑定来控制ViewModel中的选择。以下示例代码演示了这一点：

 < Window x：Class =DataGridMultiSelectSample.Window1
 xmlns = http://schemas.microsoft.com/winfx/2006/xaml/presentation
 xmlns：x =http://schemas.microsoft.com/winfx/2006/xaml
 xmlns：tk =clr-namespace：Microsoft.Windows.Controls; assembly = WPFToolkit
 Title =Window1Height =300Width =300> 
< StackPanel> 
< tk：DataGrid AutoGenerateColumns =FalseItemsSource ={Binding}EnableRowVirtualization =False> 
< tk：DataGrid.Columns> 
< tk：DataGridTextColumn Header =ValueBinding ={Binding Value}/> 
< / tk：DataGrid.Columns> 
< tk：DataGrid.RowStyle> 
< Style TargetType =tk：DataGridRow> 
< Setter Property =IsSelectedValue ={Binding IsSelected，Mode = TwoWay}/> 
< / Style> 
< / tk：DataGrid.RowStyle> 
< / tk：DataGrid> 
< Button Content =选择偶数Click =Even_Click/> 
< Button Content =选择奇数Click =Odd_Click/> 
< / StackPanel> 
< / Window> 
  

---

  System.ComponentModel; 
使用System.Windows; 
 
命名空间DataGridMultiSelectSample 
 {
 public partial class Window1 
 {
 public Window1（）
 {
 InitializeComponent（）; 
 DataContext = new [] 
 {
 new MyViewModel {Value =Able}，
 new MyViewModel {Value =Baker}，
 new MyViewModel {Value =Charlie}，
 new MyViewModel {Value =Dog}，
 new MyViewModel {Value =Fox}，
}; 
} 
 
 private void Even_Click（object sender，RoutedEventArgs e）
 {
 var array =（MyViewModel []）DataContext; （int i = 0; i  array [i] .IsSelected = i％2 == 0; 
} 
 
 private void Odd_Click（object sender，RoutedEventArgs e）
 {
 var array =（MyViewModel []）DataContext; （int i = 0; i  array [i] .IsSelected = i％2 == 1; 
} 
} 
 
 public class MyViewModel：INotifyPropertyChanged 
 {
 public string Value {get;组; } 
 
 private bool mIsSelected; 
 public bool IsSelected 
 {
 get {return mIsSelected; } 
 set 
 {
 if（mIsSelected == value）return; 
 mIsSelected = value; 
 if（PropertyChanged！= null）
 PropertyChanged（this，new PropertyChangedEventArgs（IsSelected））; 
} 
} 
 
 public event PropertyChangedEventHandler PropertyChanged; 
} 
} 
  

请确保设置 EnableRowVirtualisation =False 上的DataGrid元素，否则存在IsSelected绑定脱离kilter的风险。

I have a datagrid that is multi-select enabled. I need to change the selection in the viewmodel. However, the SelectedItems property is read only and can't be directly bound to a property in the viewmodel. So how do I signal to the view that the selection has changed?

解决方案

Andy is correct. DataGridRow.IsSelected is a Dependency Property that can be databound to control selection from the ViewModel. The following sample code demonstrates this:

<Window x:Class="DataGridMultiSelectSample.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:tk="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit"
    Title="Window1" Height="300" Width="300">
    <StackPanel>
        <tk:DataGrid AutoGenerateColumns="False" ItemsSource="{Binding}" EnableRowVirtualization="False">
            <tk:DataGrid.Columns>
                <tk:DataGridTextColumn Header="Value" Binding="{Binding Value}" />
            </tk:DataGrid.Columns>
            <tk:DataGrid.RowStyle>
                <Style TargetType="tk:DataGridRow">
                    <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
                </Style>
            </tk:DataGrid.RowStyle>
        </tk:DataGrid>
        <Button Content="Select Even" Click="Even_Click" />
        <Button Content="Select Odd" Click="Odd_Click" />
    </StackPanel>
</Window>

---

using System.ComponentModel;
using System.Windows;

namespace DataGridMultiSelectSample
{
    public partial class Window1
    {
        public Window1()
        {
            InitializeComponent();
            DataContext = new[]
                              {
                                  new MyViewModel {Value = "Able"},
                                  new MyViewModel {Value = "Baker"},
                                  new MyViewModel {Value = "Charlie"},
                                  new MyViewModel {Value = "Dog"},
                                  new MyViewModel {Value = "Fox"},
                              };
        }

        private void Even_Click(object sender, RoutedEventArgs e)
        {
            var array = (MyViewModel[]) DataContext;
            for (int i = 0; i < array.Length; ++i)
                array[i].IsSelected = i%2 == 0;
        }

        private void Odd_Click(object sender, RoutedEventArgs e)
        {
            var array = (MyViewModel[])DataContext;
            for (int i = 0; i < array.Length; ++i)
                array[i].IsSelected = i % 2 == 1;
        }
    }

    public class MyViewModel : INotifyPropertyChanged
    {
        public string Value { get; set; }

        private bool mIsSelected;
        public bool IsSelected
        {
            get { return mIsSelected; }
            set
            {
                if (mIsSelected == value) return;
                mIsSelected = value;
                if (PropertyChanged != null)
                    PropertyChanged(this, new PropertyChangedEventArgs("IsSelected"));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
    }
}

Be sure to set EnableRowVirtualisation="False" on the DataGrid element, else there's a risk that the IsSelected bindings fall out of kilter.

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