在formview控件模板列中使用两个DropDownList控件进行联动时的操作方法

1、在formview控件模板列中放入两个DropDownList控件

    2、将第一个控件按常规方法加入数据源，设置要显示的字段名和字段值，并与formview中的相应字段关联，关设置为启用autopostback

    3、给第二个DropDownList控件加入数据源，设置要显示的字段名和字段值，在其DataBound事件中加入如下代码

   Protected Sub DropDownList2_DataBound(ByVal sender As Object, ByVal e As System.EventArgs)

        Dim ddl As DropDownList = CType(sender, DropDownList)

        '指定下拉框的父控件

        Dim frmv As FormView = CType(ddl.NamingContainer, FormView)

        If Not frmv.DataItem Is Nothing Then

            Dim strcity As String = CType(frmv.DataItem, DataRowView)("SmallClassID")

            '清除下拉框的选择项

            ddl.ClearSelection()

            '在下拉框的列表项中找到值

            Dim li As ListItem = ddl.Items.FindByValue(strcity)

            If Not li Is Nothing Then

                li.Selected = True

            End If

            '找到控件DropDownList2

            ddl = CType(frmv.FindControl("DropDownList2"), DropDownList)

            '邦定数据

            If Not ddl Is Nothing Then

                ddl.DataBind()

            End If

     
4000
   End If

    End Sub

   
    4、给formview的ItemInserting事件加入如下代码：

    '当触发formview的插入数据的项时进行下列操作

    Protected Sub FormView1_ItemInserting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.FormViewInsertEventArgs) Handles FormView1.ItemInserting

        将DropDownList2的值赋给formview控件中的插入参数SmallClassID()

        Dim strprov As Int32 = CType(CType(sender, FormView).FindControl("DropDownList2"), DropDownList).SelectedValue

        e.Values("SmallClassID") = strprov

    End Sub