把GridView的内容输出到Excel的两点注意
把GridView控件的内容输出到Excel的方式网上有很多文章，其代码如下所示：
ExcelExport.aspx.cs
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.Text;
using System.IO;
public partial class DeleteConfirm : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
//Export the GridView to Excel
PrepareGridViewForExport(GridView1);
ExportGridView();
}
private void ExportGridView()
{
string attachment = "attachment; filename=Contacts.xls";
Response.ClearContent();
Response.AddHeader("content-disposition", attachment);
Response.ContentType = "application/ms-excel";
StringWriter sw = new StringWriter();
HtmlTextWriter htw = new HtmlTextWriter(sw);
GridView1.RenderControl(htw);
Response.Write(sw.ToString());
Response.End();
}
public override void VerifyRenderingInServerForm(Control control)
{
}
private void PrepareGridViewForExport(Control gv)
{
LinkButton lb = new LinkButton();
Literal l = new Literal();
string name = String.Empty;
for (int i = 0; i < gv.Controls.Count; i++)
{
if (gv.Controls[i].GetType() == typeof(LinkButton))
{
l.Text = (gv.Controls[i] as LinkButton).Text;
gv.Controls.Remove(gv.Controls[i]);
gv.Controls.AddAt(i, l);
}
else if (gv.Controls[i].GetType() == typeof(DropDownList))
{
l.Text = (gv.Controls[i] as DropDownList).SelectedItem.Text;
gv.Controls.Remove(gv.Controls[i]);
gv.Controls.AddAt(i, l);
}
else if (gv.Controls[i].GetType() == typeof(CheckBox))
{
l.Text = (gv.Controls[i] as CheckBox).Checked ? "True" : "False";
gv.Controls.Remove(gv.Controls[i]);
gv.Controls.AddAt(i, l);
}
if (gv.Controls[i].HasControls())
{
PrepareGridViewForExport(gv.Controls[i]);
}
}
}
}
通过对这段代码的测试，有两个地方应该注意，一个是重载VerifyRenderingInServerForm(Control control)方法，如果没有这个重载函数的话，GridView1.RenderControl(htw)这个语句会报一个“控件必须包含在runat=server的窗体内”错误，即使你的gridview已经包含在一个<form runat=server>的form中；另一个问题是必须在页面设置EnableEventValidation="false"，否则会有一个"registerEventValidation必须在render中"的错误。