清除 WPF 中的 DataGrid 数据

问：

因为我想要有复选框列，所以我用这种方式创建复选框 在我的 XAML 中：

<DataGrid x:Name="boxNoDetail" IsReadOnly="true" ItemsSource="{Binding}" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto" FontSize="12"  >
    <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"/>
                                                                    <!--'read only-->
                                                                </Style>
                   </DataGridCheckBoxColumn.ElementStyle>
         </DataGridCheckBoxColumn>
    </DataGrid.Columns>
</DataGrid>

我用这种方式来绑定gridview：

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

        Try
            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
            dgv.ItemsSource = dt.DefaultView
            dgv.AutoGenerateColumns = False
            dgv.CanUserAddRows = False
            Return True
        Catch ex As Exception
            logUtil.e(ex)
            Return False
        End Try

    End Function


Public Class userInterface
Function DataGridText(ByVal bind_name As String, ByVal headerName As String, 
                      Optional notVisible As Boolean = False, 
                      Optional rightAlignment As Boolean = False) As DataGridTextColumn
        Dim col_data As DataGridTextColumn = New DataGridTextColumn
        Dim c As New Style
        col_data.Binding = New Binding(bind_name)
        col_data.Header = headerName
        If notVisible Then col_data.Visibility = Visibility.Hidden
        If rightAlignment Then
            c.Setters.Add(New Setter(TextBox.TextAlignmentProperty, TextAlignment.Right))
            col_data.CellStyle = c
        End If
        Return col_data
    End Function
end class

如果我刷新数据（通过再次运行），数据网格的列将显示 2 次。为什么？？？dtFillDatagrid()

我试着一步一步地检测，发现dgv。Itemssource = Nothing 只是清晰的网格视图数据，并且没有清晰的字段。

我想问一下，如何重复使用DTFILLDATAGRID（）并解决rduplicate列的问题，或者DataTable Fill到gridView更方便？

首次加载 GridView：

第二次加载 GridView：