即使GridView在表单标记内,GridView也必须放在带有runat ="server"的表单标记内

Question

<form runat="server" id="f1">
    <div runat="server" id="d">
        grid view:
        <asp:GridView runat="server" ID="g">
        </asp:GridView>
    </div>

    <asp:TextBox runat="server" ID="t" TextMode="MultiLine" Rows="20" Columns="50"></asp:TextBox>
</form>

代码背后:

public partial class ScriptTest : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        g.DataSource = new string[] { "a", "b", "c" };
        g.DataBind();

        TextWriter tw = new StringWriter();
        HtmlTextWriter h = new HtmlTextWriter(tw);    
        d.RenderControl(h);
        t.Text = tw.ToString();
    }
}

即使GridView在runat ="server"的from标签内,我仍然会收到此错误.

请问有什么线索吗？

Answer 1

您正在调用GridView.RenderControl(htmlTextWriter),因此该页面引发了一个异常,即Server-Control是在Form外部呈现的.

您可以通过覆盖VerifyRenderingInServerForm来避免此异常

public override void VerifyRenderingInServerForm(Control control)
{
  /* Confirms that an HtmlForm control is rendered for the specified ASP.NET
     server control at run time. */
}

看到这里和这里.

Answer 2

覆盖VerifyRenderingInServerForm的替代方法是在执行渲染时从控件集合中删除网格,然后在页面加载之前完成后将其添加回来.如果您想要一些通用的帮助方法来获取网格html,这很有用,因为您不必记住添加覆盖.

Control parent = grid.Parent;
int GridIndex = 0;
if (parent != null)
{
    GridIndex = parent.Controls.IndexOf(grid);
    parent.Controls.Remove(grid);
}

grid.RenderControl(hw);

if (parent != null)
{
    parent.Controls.AddAt(GridIndex, grid);
}

避免覆盖的另一种方法是:

grid.RenderBeginTag(hw);
grid.HeaderRow.RenderControl(hw);
foreach (GridViewRow row in grid.Rows)
{
    row.RenderControl(hw);
}
grid.FooterRow.RenderControl(hw);
grid.RenderEndTag(hw);

Answer 3

在你的Page_Load添加之后:

public override void VerifyRenderingInServerForm(Control control)
{
    //base.VerifyRenderingInServerForm(control);
}

请注意,我在该功能中没有做任何事情.

编辑:蒂姆回答同样的事情.:)你也可以在这里找到答案