wpf中为DataGrid添加checkbox支持多选全选 · WPF编程之路

项目中用到DataGrid，需要在第一列添加checkbox，可以多选、全选。其中涉及的概念DataTemplate， DataGridCellStyle， DataGridCellControlTemplate，Binding， OnPropertyChanged等。有下面是实现思路: 1.继承INotifyPropertyChanged接口，实现OnPropertyChanged方法： public abstract class ViewModelBase : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; /// <summary> /// Raises this object's PropertyChanged event. /// </summary> /// <param name="propertyName">The property that has a new value</param> protected void OnPropertyChanged(string propertyName) { PropertyChangedEventHandler handler = PropertyChanged; if (null != handler) { handler(this, new PropertyChangedEventArgs(propertyName)); } } //.................. } 2. 实现viewModel，添加IsSelected属性，存储当前多选状态 private bool _isSelected = true; public bool IsSelected { get { return _isSelected; } set { _isSelected = value; OnPropertyChanged("IsSelected"); } } 3.在VM/Model准备好后，我们接下来开始对DataGrid进行style自定义 4.准备checkbox的DataTemplate： <DataTemplate x:Key="CheckboxDataTemplate1"> <Grid> <CheckBox x:Name="_chkSelected" Height="16" HorizontalAlignment="Center" VerticalAlignment="Center" Background="{x:Null}" VerticalContentAlignment="Center" HorizontalContentAlignment="Center" Click="_chkSelected_OnClick" IsThreeState="False" IsChecked="{Binding IsSelected, Mode=OneWay, FallbackValue=True}" /> </Grid> </DataTemplate> 此示例中checkbox只有简单的2种状态， 1）IsChecked属性绑定VM的IsSelected属性； 2）Mode为OneWay是因为我们需求是用户可以多选行然后点击某行头选中多行。此功能在Click事件中遍历当前所有选中的行，然后更改其VM的IsSelected属性。因此不需要TwoWay模式； 3）在Binding中添加了FallbackValue, 此属性指示当binding失败时给出的默认值。此例中因为DataTemplate也应用在列头，而列头的DataContext和DataGridRow不同； 4）在Click事件处理函数中，判断当前点击的列头还是行头，更改对应DataContext的IsSelected属性。如： private void _chkSelected_OnClick(object sender, RoutedEventArgs e) { CheckBox chkSelected = e.OriginalSource as CheckBox; if (null == chkSelected) { return; } var studyModel = chkSelected.DataContext as StudyModel; bool isChecked = chkSelected.IsChecked.HasValue ? chkSelected.IsChecked.Value : true; FrameworkElement templateParent = chkSelected.TemplatedParent is FrameworkElement ? (chkSelected.TemplatedParent as FrameworkElement).TemplatedParent as FrameworkElement : null; if (templateParent is DataGridColumnHeader) { MainViewModel mvm = this.DataContext as MainViewModel; if (null != mvm) { foreach (var sm in mvm.StudyList) { sm.IsSelected = isChecked; } } } else if (templateParent is DataGridCell) { if (null != studyModel && null != this._grdStudyList.SelectedItems && this._grdStudyList.SelectedItems.Contains(studyModel)) { foreach (var otherSelected in this._grdStudyList.SelectedItems.OfType<StudyModel>()) { otherSelected.IsSelected = isChecked; } } } } 其中MainViewModel为主VM，其包含一个ObservableCollection<StudyModel> StudyList，而StudyModel包含IsSelected属性，二者都实现OnpropertyChanged方法； _grdStudyList为xaml中的DataGrid 5.应用DataTemplate到DataGridColumnHeader和DataGridCell，如： <Style x:Key="DataGridCheckboxColumnHeaderStyle1" TargetType="{x:Type DataGridColumnHeader}"> <Setter Property="ContentTemplate" Value="{DynamicResource CheckboxDataTemplate1}"/> <Setter Property="HorizontalAlignment" Value="Stretch"/> <Setter Property="VerticalAlignment" Value="Stretch"/> </Style> <Style x:Key="DataGridCheckboxCellStyle1" TargetType="{x:Type DataGridCell}"> <Setter Property="Padding" Value="20,0"/> <Setter Property="ContentTemplate" Value="{DynamicResource CheckboxDataTemplate1}"/> <Setter Property="Background" Value="#FFC1C1C1"/> <Setter Property="BorderBrush" Value="{x:Null}"/> <Setter Property="BorderThickness" Value="0"/> <Setter Property="Template" Value="{DynamicResource DataGridCheckboxCellControlTemplate1}"/> <Style.Triggers> <Trigger Property="IsSelected" Value="True"> <Setter Property="Background" Value="#FFC1C1C1"/> <Setter Property="BorderBrush" Value="{x:Null}"/> </Trigger> </Style.Triggers> </Style> <ControlTemplate x:Key="DataGridCheckboxCellControlTemplate1" TargetType="{x:Type DataGridCell}"> <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" SnapsToDevicePixels="True"> <ContentPresenter ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" ContentStringFormat="{TemplateBinding ContentStringFormat}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/> </Border> </ControlTemplate> 6.应用CellStyle和HeaderStyle到DataGrid： <DataGrid ~~~ x:Name="_grdStudyList" ItemsSource="{Binding StudyList}" AutoGenerateColumns="False" FrozenColumnCount="1" Background="#FF999797"> ~~~ ~~~ <DataGrid.Columns> ~~~ ~~~ <DataGridCheckBoxColumn ~~~ ~~~ x:Name="_dtcSelected" Header="" HeaderStyle="{StaticResource DataGridCheckboxColumnHeaderStyle1}" CellStyle="{StaticResource DataGridCheckboxCellStyle1}" MinWidth="60" CanUserReorder="False" MaxWidth="60"/> ~~~