WPF中重复调用dtFillDatagrid致DataGrid列重复的解决方法

一、直接解决重复列问题 #

核心问题是每次调用dtFillDatagrid时，仅清空了数据但未清除之前手动添加的列，导致重复累加。只需在添加新列前，保留XAML定义的CheckBox列，移除其余旧列即可：

修改dtFillDatagrid方法，加入列清理逻辑：

Function dtFillDatagrid(ByVal dt As DataTable, ByVal dgv As DataGrid) As Boolean
    dgv.ItemsSource = Nothing
    Dim myUI As userInterface = New userInterface

    Try
        ' 保留XAML的CheckBox列，移除其他所有旧列
        While dgv.Columns.Count > 1
            dgv.Columns.RemoveAt(1)
        End While

        For Each column As DataColumn In dt.Columns
            Dim name As String = column.ColumnName
            If name = "IsSelected" Then
            ElseIf name = "sn" Then
                dgv.Columns.Add(myUI.DataGridText(name, name, True))            
            Else
                dgv.Columns.Add(myUI.DataGridText(name, name))
            End If
        Next
        ' 先设置自动生成列属性，再绑定数据源
        dgv.AutoGenerateColumns = False
        dgv.CanUserAddRows = False
        dgv.ItemsSource = dt.DefaultView
        Return True
    Catch ex As Exception
        logUtil.e(ex)
        Return False
    End Try
End Function

二、更便捷的DataTable绑定方式 #

手动维护列集合容易出错，推荐利用DataGrid的自动列生成特性，结合事件自定义列行为，彻底避免重复列问题：

1. 修改XAML配置 #

保留CheckBox列，开启自动生成列并绑定事件：

<DataGrid x:Name="boxNoDetail" 
          IsReadOnly="true" 
          ItemsSource="{Binding}" 
          HorizontalScrollBarVisibility="Auto" 
          VerticalScrollBarVisibility="Auto" 
          FontSize="12"
          AutoGenerateColumns="True"
          AutoGeneratingColumn="boxNoDetail_AutoGeneratingColumn">
    <DataGrid.Columns>
        <DataGridCheckBoxColumn Header="Checked"  
                                Binding="{Binding IsChecked, UpdateSourceTrigger=PropertyChanged}">
            <DataGridCheckBoxColumn.ElementStyle>
                <Style TargetType="{x:Type CheckBox}" BasedOn="{StaticResource {x:Type CheckBox}}">
                    <Setter Property="VerticalAlignment" Value="Center"/>
                    <Setter Property="HorizontalAlignment" Value="Center"/>
                    <Setter Property="IsHitTestVisible" Value="False"/>
                </Style>
            </DataGridCheckBoxColumn.ElementStyle>
        </DataGridCheckBoxColumn>
    </DataGrid.Columns>
</DataGrid>

2. 后台实现列自定义逻辑 #

在窗口/用户控件后台添加事件处理，控制列的显示、样式：

Private Sub boxNoDetail_AutoGeneratingColumn(sender As Object, e As DataGridAutoGeneratingColumnEventArgs)
    Dim columnName As String = e.PropertyName
    ' 跳过不需要显示的列
    If columnName = "IsSelected" Then
        e.Cancel = True
        Return
    End If
    ' 设置列头文本
    e.Column.Header = columnName
    ' 隐藏sn列
    If columnName = "sn" Then
        e.Column.Visibility = Visibility.Hidden
        Return
    End If
    ' 可扩展：为指定列设置右对齐
    ' If columnName = "Amount" Then
    '     Dim textCol = TryCast(e.Column, DataGridTextColumn)
    '     If textCol IsNot Nothing Then
    '         Dim style As New Style(GetType(TextBox))
    '         style.Setters.Add(New Setter(TextBox.TextAlignmentProperty, TextAlignment.Right))
    '         textCol.CellStyle = style
    '     End If
    ' End If
End Sub

3. 简化绑定方法 #

现在绑定DataTable只需几行代码，无需手动添加列：

Function dtFillDatagrid(ByVal dt As DataTable, ByVal dgv As DataGrid) As Boolean
    Try
        dgv.CanUserAddRows = False
        dgv.ItemsSource = dt.DefaultView
        Return True
    Catch ex As Exception
        logUtil.e(ex)
        Return False
    End Try
End Function

这种方式利用WPF内置机制减少手动代码，既避免重复列问题，也更符合WPF设计思想。

内容的提问来源于stack exchange，提问作者TWMonk