如何在WPF的C#后台代码中设置DataGrid列宽为文本自适应/Auto？

我在后台代码中创建DataGrid并添加到TabItem中（每个TabItem对应一个DataGrid），但始终遇到列宽过窄、数据难以阅读的问题。复制已有XAML中的设置无效，就算直接在XAML里加DataGrid用相同设置，结果还是一样。

XAML用户控件代码 #

<UserControl>
    <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">
        <DockPanel Background="#A0A1A2" Height="Auto" Width="Auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" LastChildFill="False">
     ...........
      <TabControl>
      (tabitem will be generated through loop with adding datagrids into the tabitem in code behind)
      </TabControl>
     </DockPanel>
   </ScrollViewer>
</UserControl>

后台代码 #

dt_grid1 = new DataGrid();
dt_grid2 = new DataGrid();

InitializeComponent();

// Setting up the Datagrids:
Dispatcher.Invoke(() =>
{
    // Datagrid1:
    dt_grid1.CanUserAddRows = false;
    dt_grid1.CanUserDeleteRows = false;
    dt_grid1.CanUserReorderColumns = false;
    dt_grid1.CanUserResizeColumns = false;
    dt_grid1.CanUserResizeRows = false;
    dt_grid1.CanUserSortColumns = false;
    dt_grid1.AutoGenerateColumns = false;
    dt_grid1.IsReadOnly = true;
    dt_grid1.Margin = new Thickness(5);
    dt_grid1.VerticalAlignment = VerticalAlignment.Stretch;
    dt_grid1.HorizontalAlignment = HorizontalAlignment.Stretch;
    dt_grid1.SelectionMode = DataGridSelectionMode.Extended;
    //dt_grid1.ColumnWidth = new DataGridLength(50, DataGridLengthUnitType.Star);

    // Datagrid2:
    dt_grid2.CanUserAddRows = false;
    dt_grid2.CanUserDeleteRows = false;
    dt_grid2.CanUserReorderColumns = false;
    dt_grid2.CanUserResizeColumns = false;
    dt_grid2.CanUserResizeRows = false;
    dt_grid2.CanUserSortColumns = false;
    dt_grid2.AutoGenerateColumns = false;
    dt_grid2.IsReadOnly = true;
    dt_grid2.Margin = new Thickness(5);
    dt_grid2.VerticalAlignment = VerticalAlignment.Stretch;
    dt_grid2.HorizontalAlignment = HorizontalAlignment.Stretch;
    dt_grid2.SelectionMode = DataGridSelectionMode.Extended;
    //dt_grid2.ColumnWidth = new DataGridLength(50, DataGridLengthUnitType.Star);
});

问题效果 #

解决方法 #

1. 启用列宽自适应或星号分配
   你注释掉的ColumnWidth星号设置是关键，星号模式会让列按比例填充可用宽度。取消注释并调整参数：

   dt_grid1.ColumnWidth = new DataGridLength(1, DataGridLengthUnitType.Star);
   dt_grid2.ColumnWidth = new DataGridLength(1, DataGridLengthUnitType.Star);
   

   也可以用自适应内容模式，让列自动匹配内容宽度：

   dt_grid1.ColumnWidth = DataGridLength.Auto;
   

   若要兼顾自适应和避免列过宽，可设置最大宽度：

   dt_grid1.ColumnWidth = new DataGridLength(0, DataGridLengthUnitType.Auto);
   dt_grid1.MaxColumnWidth = 200;
   

2. 修复容器布局约束

   • 把DockPanel的LastChildFill改为True，确保TabControl能填充剩余空间：

     <DockPanel Background="#A0A1A2" Height="Auto" Width="Auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" LastChildFill="True">
     

   • 后台添加DataGrid到TabItem时，将DataGrid放入可拉伸的容器（如Grid）中：

     TabItem tab1 = new TabItem();
     Grid tabContent = new Grid();
     tabContent.Children.Add(dt_grid1);
     tab1.Content = tabContent;
     

3. 调整外层ScrollViewer设置
   外层ScrollViewer的水平滚动会让内部容器优先使用最小宽度，可将HorizontalScrollBarVisibility改为Disabled，强制内部容器填充宽度：

   <ScrollViewer HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto">
   

   若必须保留水平滚动，需确保TabControl、TabItem内容都设置HorizontalAlignment="Stretch"，同时给DataGrid设置明确的最小宽度或星号列宽。

4. 手动设置列宽（关闭自动生成列时）
   因为你关闭了AutoGenerateColumns，需要给每个手动创建的列单独设置宽度：

   DataGridTextColumn col = new DataGridTextColumn();
   col.Header = "列名";
   col.Binding = new Binding("字段名");
   col.Width = new DataGridLength(1, DataGridLengthUnitType.Star);
   dt_grid1.Columns.Add(col);
   

内容的提问来源于stack exchange，提问作者user23077506