如何访问GridView的HeaderTemplate中的控件

Question

我想在GridView的标题中有一个DropDownList.在我的代码隐藏中,我似乎无法访问它.这是HeaderTemplate:

<asp:TemplateField SortExpression="EXCEPTION_TYPE">
    <HeaderTemplate>
        <asp:Label ID="TypeId" runat="server" Text="Type" ></asp:Label>
        <asp:DropDownList ID="TypeFilter" runat="server" AutoPostBack="true">
        </asp:DropDownList>
    </HeaderTemplate>
    ...
</asp:TemplateField>

这里是代码背后的部分,我试图访问控件'TypeFilter'.

protected void ObjectDataSource1_Selected(object sender, 
                                          ObjectDataSourceStatusEventArgs e)
{
    DataTable dt = (DataTable)e.ReturnValue;
    int NumberOfRows = dt.Rows.Count;
    TotalCount.Text = NumberOfRows.ToString();
    DataView dv = new DataView(dt);
    DataTable types = dv.ToTable(true, new string[] { "EXCEPTION_TYPE" });
    DropDownList typeFilter = (DropDownList)GridView1.FindControl("TypeFilter");
    typeFilter.DataSource = types;
    typeFilter.DataBind();

}

您会注意到我正在尝试使用FindControl来获取对DropDownList控件的引用.此调用返回null而不是返回控件.如何访问控件？

Answer 1

使用Repeater,您可以通过在OnItemDataBoundEvent中使用FindControl来访问headerTemplate项,如下所示:

RepeaterItem item = (RepeaterItem)e.Item;
if (item.ItemType == ListItemType.Header) {
    item.FindControl("control"); //goes here
}

这对GridViews也有用吗？