WPF里借助附加属性让DataGrid显示行号

大部分表格，都有显示行号的需求。

WPF里的DataGrid显示行号，一般如下方式显示：

 

 在后台代码里写上相应的事件处理方法：

 

 

 

运行效果如下：

 

 但是，这样需要对项目里的所有需要显示行号的DataGrid都要写重复的代码。

十分不优雅。

下面介绍一种通过附加属性的方式，把上面的代码进行一下封装。

然后每次应用的时候，只需要简单的给DataGrid设置一下属性即可。

 

 

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#region DisplayRowNumber         public static bool GetDisplayRowNumber(DependencyObject obj)         {             return (bool)obj.GetValue(DisplayRowNumberProperty);         }           [AttachedPropertyBrowsableForType(typeof(DataGrid))]         public static void SetDisplayRowNumber(DependencyObject obj, bool value)         {             obj.SetValue(DisplayRowNumberProperty, value);         }           /// <summary>         /// 设置是否显示行号         /// </summary>         public static readonly DependencyProperty DisplayRowNumberProperty =             DependencyProperty.RegisterAttached("DisplayRowNumber",                                                 typeof(bool),                                                 typeof(DataGridHelper),                                                 new PropertyMetadata(false, OnDisplayRowNumberChanged));           private static void OnDisplayRowNumberChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)         {             DataGrid grid = d as DataGrid;             if (grid == null)             {                 return;             }               if ((bool)e.NewValue)             {                 grid.LoadingRow += OnGridLoadingRow;                 grid.UnloadingRow += OnGridUnloadingRow;             }             else             {                 grid.LoadingRow -= OnGridLoadingRow;                 grid.UnloadingRow -= OnGridUnloadingRow;             }         }           private static void RefreshDataGridRowNumber(object sender)         {             DataGrid grid = sender as DataGrid;             if (grid == null)             {                 return;             }               foreach (var item in grid.Items)             {                 var row = (DataGridRow)grid.ItemContainerGenerator.ContainerFromItem(item);                 if (row == null)                 {                     return;                 }                 row.Header = row.GetIndex() + 1;             }         }           private static void OnGridUnloadingRow(object sender, DataGridRowEventArgs e)         {             RefreshDataGridRowNumber(sender);         }           private static void OnGridLoadingRow(object sender, DataGridRowEventArgs e)         {             RefreshDataGridRowNumber(sender);         }           #endregion

　　

总结，主要运用了WPF中附加属性的技术。