GridView 必须放置在带有 runat="server" 的表单标签内.即使在 GridView 位于表单标签内之后 [英] GridView must be placed inside a form tag with runat="server" even after the GridView is within a form tag

问题描述

<div runat="server" id="d">网格视图:<asp:GridView runat="server" ID="g"></asp:GridView>

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

背后的代码:

公共部分类 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 位于带有 runat="server" 的 from 标记内，我仍然收到此错误.

请问有什么线索吗?

解决方案

您正在调用 GridView.RenderControl(htmlTextWriter)，因此页面引发异常，即服务器控件在形式.

您可以通过覆盖 VerifyRenderingInServerForm 来避免这种执行

public override void VerifyRenderingInServerForm(Control control){/* 确认为指定的 ASP.NET 呈现一个 HtmlForm 控件运行时的服务器控制.*/}

请参阅此处和此处.

<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>

Code behind:

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();
    }
}

Even the GridView is within a from tag with runat="server", still I am getting this error.

Any clues please ?

解决方案

You are calling GridView.RenderControl(htmlTextWriter), hence the page raises an exception that a Server-Control was rendered outside of a Form.

You could avoid this execption by overriding VerifyRenderingInServerForm

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

See here and here.

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