风格通过AttachedProperty

Question

所有DataGridTextColumns我试图做的是创建一个Style在Datagrid以应用在所有DataGridTextColumns一个自动换行没有显式地设置这样的。

<DataGrid ItemsSource="{Binding Lines}"> 
    <DataGrid.Columns> 
     <DataGridTextColumn Header="Column1" Binding="{Binding Path=Result1}"> 
      <DataGridTextColumn.ElementStyle> 
       <Style TargetType="{x:Type TextBlock}"> 
        <Setter Property="TextWrapping" Value="Wrap"/> 
       </Style> 
      </DataGridTextColumn.ElementStyle> 
     </DataGridTextColumn> 
    </DataGrid.Columns> 
</DataGrid> 

遗憾的是无法使用一些Style如下直接，因为DataGridTextColumn不是FrameworkElement。

<Style TargetType="{x:Type TextBlock}" x:Key="WrapText"> 
    <Setter Property="TextWrapping" Value="Wrap"/> 
</Style> 

我发现这个解决办法https://stackoverflow.com/a/2640862/5381620通过RayBurns，并试图它是如何工作的弄清楚。但是，我是新来的附加属性，因此不明白为什么它不起作用。

c＃代码似乎没问题。

public class MyDataGridHelper : DependencyObject 
{ 
    private static readonly DependencyProperty TextColumnStyleProperty = DependencyProperty.RegisterAttached("TextColumnStyle", typeof(Style), typeof(MyDataGridHelper), new PropertyMetadata 
    { 
     PropertyChangedCallback = (obj, e) => 
     { 
      var grid = (DataGrid)obj; 
      if (e.OldValue == null && e.NewValue != null) 
       grid.Columns.CollectionChanged += (obj2, e2) => 
       { 
        UpdateColumnStyles(grid); 
       }; 
     } 
    }); 

    public static void SetTextColumnStyle(DependencyObject element, Style value) 
    { 
     element.SetValue(TextColumnStyleProperty, value); 
    } 
    public static Style GetTextColumnStyle(DependencyObject element) 
    { 
     return (Style)element.GetValue(TextColumnStyleProperty); 
    } 

    private static void UpdateColumnStyles(DataGrid grid) 
    { 
     var style = GetTextColumnStyle(grid); 
     foreach (var column in grid.Columns.OfType<DataGridTextColumn>()) 
      foreach (var setter in style.Setters.OfType<Setter>()) 
       if (setter.Value is BindingBase) 
        BindingOperations.SetBinding(column, setter.Property, (BindingBase)setter.Value); 
       else 
        column.SetValue(setter.Property, setter.Value); 
    } 
} 

我完全困惑的是当我们弄清楚风格二传手。 目前我正在尝试这种方式，这显然不起作用，但实际上我不知道这个目标类型应该是什么样子。

<local:MyDataGridHelper.TextColumnStyle> 
    <Style TargetType="FrameworkElement"> 
     <Setter Property="TextBlock.TextWrapping" Value="Wrap"/> 
    </Style> 
</local:MyDataGridHelper.TextColumnStyle> 

Answer 1

应设置列ElementStyle的附加属性的值：

public class MyDataGridHelper : DependencyObject 
{ 
    private static readonly DependencyProperty TextColumnStyleProperty = 
     DependencyProperty.RegisterAttached("TextColumnStyle", typeof(Style), typeof(MyDataGridHelper), new PropertyMetadata 
    { 
     PropertyChangedCallback = (obj, e) => 
     { 
      var grid = (DataGrid)obj; 
      if (e.OldValue == null && e.NewValue != null) 
       grid.Columns.CollectionChanged += (obj2, e2) => 
       { 
        UpdateColumnStyles(grid); 
       }; 
     } 
    }); 

    public static void SetTextColumnStyle(DependencyObject element, Style value) 
    { 
     element.SetValue(TextColumnStyleProperty, value); 
    } 
    public static Style GetTextColumnStyle(DependencyObject element) 
    { 
     return (Style)element.GetValue(TextColumnStyleProperty); 
    } 

    private static void UpdateColumnStyles(DataGrid grid) 
    { 
     var style = GetTextColumnStyle(grid); 
     foreach (var column in grid.Columns.OfType<DataGridTextColumn>()) 
      column.ElementStyle = style; 
    } 
} 

用法：

<DataGrid> 
    <local:MyDataGridHelper.TextColumnStyle> 
     <Style TargetType="TextBlock"> 
      <Setter Property="Foreground" Value="Red"/> 
      <Setter Property="TextWrapping" Value="Wrap"/> 
     </Style> 
    </local:MyDataGridHelper.TextColumnStyle> 
    ... 
</DataGrid>