只能在执行 Render() 的过程中调用问题之解决方案

只能在执行 Render() 的过程中调用 RegisterForEventValidation(RegisterForEventValidation can only be called during Render(); )

当用GridView导出Execl的时候，会发生只能在执行 Render() 的过程中调用 RegisterForEventValidation的错误提示。
有两种方法可以解决以上问题：
1.修改web.config(不推荐)
2.直接在导出Execl的页面修改

<%

@ Page Language="C#" EnableEventValidati

on = "false" AutoEventWireup="true"

 CodeFile="ExportGridView.aspx.cs" Inherits="ExportGridView" %>

附：Gridview导出Execl可分页全部导出代码(C#)

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using System.IO;

public partial class EXportTest : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            BindData(); 
        }

    }
    
    private string ConnectionString
    {

        get { return @"Server=localhost;Database=Northwind;
        Trusted_Connection=true"; }

    }

    

    private void BindData()
    {
        // make the query 
        string query = "SELECT * FROM Categories";
        SqlConnection myConnection = new SqlConnection(ConnectionString);
        SqlDataAdapter ad = new SqlDataAdapter(query, myConnection);
        DataSet ds = new DataSet();
        ad.Fill(ds, "Categories");
        GridView1.DataSource = ds;
        GridView1.DataBind(); 

        /**//* It's a good idea if you can Cache the DataSet */

    }

    public override void VerifyRenderingInServerForm(Control control)
    {

        // Confirms that an HtmlForm control is rendered for
        the specified ASP.NET server control at run time.

    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        Response.Clear();

        Response.AddHeader("content-disposition",
        "attachment;filename=FileName.xls");

        Response.Charset = "";

        // If you want the option to open the Excel file without saving than

        // comment out the line below

        // Response.Cache.SetCacheability(HttpCacheability.NoCache);

        Response.ContentType = "application/vnd.xls";

        System.IO.StringWriter stringWrite = new System.IO.StringWriter();

        System.Web.UI.HtmlTextWriter htmlWrite =
        new HtmlTextWriter(stringWrite);

        // turn off paging 
        GridView1.AllowPaging = false;
        BindData(); 
        

        GridView1.RenderControl(htmlWrite);

        Response.Write(stringWrite.ToString());

        Response.End();

        // turn the paging on again 
        GridView1.AllowPaging = true;
        BindData();
        
    }
   
    protected void GridView1_PageIndexChanging(object sender,
    GridViewPageEventArgs e)
    {
        GridView1.PageIndex = e.NewPageIndex;
        BindData(); 
    }
}

VB.net:(GridView直接帮定DataSource控件)

Imports Microsoft.VisualBasic
Imports System
Imports System.IO


Partial Class ManageContentsClass ManageContents
    Inherits System.Web.UI.Page

    Protected Sub Page_Load()Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        'If Not Me.IsPostBack Then
        '    If Request.QueryString("username") <> "xucanzhao" Then
        '        Response.Redirect("default.aspx?returnUrl=nousername")
        '    End If
        'End If
        ' ClientScript.RegisterStartupScript(Me.GetType(), "haha", "")
    End Sub

    Protected Sub btnExportExcel_Click()Sub btnExportExcel_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnExportExcel.Click
        Response.Clear()
        Response.Buffer = True

        Response.Charset = "utf-8"

        Response.AddHeader("Content-Disposition", "attachment;filename=FileFlow.xls")
        Response.ContentType = "application/ms-excel"
        Dim strWriter As New StringWriter()
        Dim htw As New HtmlTextWriter(strWriter)
        GridView1.AllowPaging = False
        GridView1.DataBind()
        GridView1.RenderControl(htw)
        Response.Write(strWriter.ToString)
        Response.End()
        GridView1.AllowPaging = True
        GridView1.DataBind()
    End Sub
    Public Overrides Sub verifyRenderingInServerForm()Sub verifyRenderingInServerForm(ByVal control As Control)

    End Sub
End Class

 ****

类型“GridView”的控件“GridView1”必须放在具有 runat=server 的窗体标记内。

 

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