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)<pages enableEventValidation ="false" ></pages>

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", "<script>alert('haha');</script>")

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);

}