假设网格列的内置编辑器提供特定值的下拉列表，并且必须根据其他行的取值来筛选列表项。 例如，网格包含两个列：第一个列用于编辑 Country 字段，而第二个列提供选定国家的城市列表。 要只显示适当的取值，应该根据第一个列的取值来筛选第二个列的取值。

对于需要筛选下拉列表取值的列，可以使用 LookUpEdit 或 ComboBoxEdit 内置编辑器。 当使用 LookUpEdit 编辑器时，可以直接把在下拉列表中显示的项指派到编辑器的 DataSource 属性。 ComboBoxEdit 控件没有提供该属性。 应该通过把列表项添加到此编辑器的 Items 集合中，完成人工装载下拉列表。

要筛选列的下拉列表值，则接管 ColumnView.ShownEditor 事件。 在此事件中，必须按要求筛选活动编辑器的下拉列表。 请参阅下面的示例代码。

要获得示例的完整源代码，请参阅下面的知识库文章 (需要因特网连接)：

How to filter a second LookUp column based on a first LookUp column's value

C#CopyCode image复制代码
using DevExpress.XtraEditors;
using DevExpress.XtraGrid.Views.Grid;

private DataView clone = null;

private void gridView1_ShownEditor(object sender, System.EventArgs e) {
    GridView view = sender as GridView;
    if (view.FocusedColumn.FieldName == "CityCode" && view.ActiveEditor is LookUpEdit) {
        Text = view.ActiveEditor.Parent.Name;
        DevExpress.XtraEditors.LookUpEdit edit;
        edit = (LookUpEdit)view.ActiveEditor;

        DataTable table = edit.Properties.LookUpData.DataSource as DataTable;
        clone = new DataView(table);
        DataRow row = view.GetDataRow(view.FocusedRowHandle);
        clone.RowFilter = "[CountryCode] = " + row["CountryCode"].ToString();
        edit.Properties.LookUpData.DataSource = clone;
    }
}

private void gridView1_HiddenEditor(object sender, System.EventArgs e) {
    if (clone != null) {
        clone.Dispose();
        clone = null;
    }
}
Visual BasicCopyCode image复制代码
Imports DevExpress.XtraEditors
Imports DevExpress.XtraGrid.Views.Grid

Private clone As DataView

Private Sub GridView1_ShownEditor(ByVal sender As Object, _
  ByVal e As System.EventArgs) Handles GridView1.ShownEditor
    Dim view As GridView = CType(sender, GridView)
    If view.FocusedColumn.FieldName = "CityCode" AndAlso _
      TypeOf view.ActiveEditor Is LookUpEdit Then
        Dim edit As LookUpEdit
        Dim table As DataTable
        Dim row As DataRow

        edit = CType(view.ActiveEditor, .LookUpEdit)

        table = CType(edit.Properties.DataSource, DataTable)
        clone = New DataView(table)
        row = view.GetDataRow(view.FocusedRowHandle)
        clone.RowFilter = "[CountryCode] = " + row("CountryCode").ToString()
        edit.Properties.DataSource = clone
    End If
End Sub

Private Sub GridView1_HiddenEditor(ByVal sender As Object, _
  ByVal e As System.EventArgs) Handles GridView1.HiddenEditor
    If Not clone Is Nothing Then
        clone.Dispose()
        clone = Nothing
    End If
End Sub