你有没有尝试过这样的事情？

Have you tried something like this ?

public static string RenderView(string path)
{
    Page pageHolder = new Page();
    System.Web.UI.HtmlControls.HtmlForm formHolder = new System.Web.UI.HtmlControls.HtmlForm();
    pageHolder.Controls.Add(formHolder );

    UserControl viewControl = (UserControl)pageHolder.LoadControl(path);

    formHolder.Controls.Add(viewControl);

    StringWriter output = new StringWriter();
    HttpContext.Current.Server.Execute(pageHolder, output, false);

    return output.ToString();
}

希望这将有助于