简介:
在本文中我们将具体介绍如何将ASP.Net 2.0下的GridView导出为Excel.
本文的焦点是Gridview导为Excel功能和它的数据绑定只出口示范功能.
本文代码可以用来导出为Excel的功能但不局限于这个部分,还可以在很多项目中使用。
Step 1: Setup your web page with the Gridview
这里我假定你满足:在一个页面中有个名为GridView1的GridView。在GridView中我们绑定了一个名为ContactPhone的SQL数据库。接下来的代码就是如何将GridView导出为Excel并且不依赖于具体的数据绑定还具有场景自改变能力。
ContactPhone Table Structure:
Column Name |
Type |
ContactID |
Int (Identity) |
FName |
Varchar(50) |
LName |
Varchar(50) |
ContactPhone |
Varchar(20) |
Step: The Actual Export
这段代码是直接输出为Excel的,你也可以改变content-disposition和ContentType以输出不同的类型。
string attachment = ” attachment; filename=Contacts.xls ” ;
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Response.ClearContent();
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Response.AddHeader( ” content-disposition ” , attachment);
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Response.ContentType = ” application/ms-excel ” ;
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StringWriter sw = new StringWriter();
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HtmlTextWriter htw = new HtmlTextWriter(sw);
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GridView1.RenderControl(htw);
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Response.Write(sw.ToString());
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Response.End();
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如果你运行以上代码,将返回一个HttpException:
‘GridView1’是一个类型为’GridView’的控件,必须为其添加一个runat=server标记.
为避免这个错误,我们添加以下代码:
public override void VerifyRenderingInServerForm(Control control)
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{
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5}
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Step : Convert the contents
如果GridView中有其它控件,比如Checkboxes,Dropdownlists,我们需要将它转换为其相关的值,以下递归就用于导出Excel前的准备工作,将各类控件转换为其相关值.
private void PrepareGridViewForExport(Control gv)
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{
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5 LinkButton lb = new LinkButton();
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7 Literal l = new Literal();
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9 string name = String.Empty;
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11 for (int i = 0; i < gv.Controls.Count; i++)
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13 {
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15 if (gv.Controls[i].GetType() == typeof(LinkButton))
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17 {
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19 l.Text = (gv.Controls[i] as LinkButton).Text;
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21 gv.Controls.Remove(gv.Controls[i]);
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23 gv.Controls.AddAt(i, l);
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25 }
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27 else if (gv.Controls[i].GetType() == typeof(DropDownList))
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29 {
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31 l.Text = (gv.Controls[i] as DropDownList).SelectedItem.Text;
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33 gv.Controls.Remove(gv.Controls[i]);
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35 gv.Controls.AddAt(i, l);
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37 }
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39 else if (gv.Controls[i].GetType() == typeof(CheckBox))
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41 {
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43 l.Text = (gv.Controls[i] as CheckBox).Checked? “True” : “False”;
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45 gv.Controls.Remove(gv.Controls[i]);
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47 gv.Controls.AddAt(i, l);
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49 }
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51 if (gv.Controls[i].HasControls())
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53 {
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55 PrepareGridViewForExport(gv.Controls[i]);
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57 }
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59}
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Code Listing:
Image: Page Design
Image : Sample in action
Image: Export to Excel button is clicked
Image: GridView contents exported to Excel
ExcelExport.aspx
1<%@ Page Language=”C#” AutoEventWireup=”true” CodeFile=”ExportExcel.aspx.cs” Inherits=”DeleteConfirm” %>
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3
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5<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>
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7
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9<html xmlns=”http://www.w3.org/1999/xhtml” >
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11<head runat=”server”>
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13<title>Contacts Listing</title>
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15</head>
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17<body>
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19<form id=”form1″ runat=”server”>
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21<div>
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23<strong><span style=”font-size: small; font-family: Arial; text-decoration: underline”>
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25Contacts Listing
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27 <asp:Button ID=”Button1″ runat=”server” OnClick=”Button1_Click” Text=”Export To Excel” /></span></strong><br />
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29<br />
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31<asp:GridView ID=”GridView1″ runat=”server” AutoGenerateColumns=”False” DataKeyNames=”ContactID”
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33DataSourceID=”SqlDataSource1″ EmptyDataText=”There are no data records to display.” style=”font-size: small; font-family: Arial” BackColor=”White” BorderColor=”#DEDFDE” BorderStyle=”None” BorderWidth=”1px” CellPadding=”4″ ForeColor=”Black” GridLines=”Vertical”>
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35<Columns>
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37<asp:BoundField DataField=”ContactID” HeaderText=”ContactID” ReadOnly=”True” SortExpression=”ContactID” Visible=”False” />
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39<asp:BoundField DataField=”FName” HeaderText=”First Name” SortExpression=”FName” />
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41<asp:BoundField DataField=”LName” HeaderText=”Last Name” SortExpression=”LName” />
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43<asp:BoundField DataField=”ContactPhone” HeaderText=”Phone” SortExpression=”ContactPhone” />
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45<asp:TemplateField HeaderText=”Favorites”>
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47<ItemTemplate>
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49
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51 <asp:CheckBox ID=”CheckBox1″ runat=”server” />
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53</ItemTemplate></asp:TemplateField>
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55</Columns>
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57<FooterStyle BackColor=”#CCCC99″ />
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59<RowStyle BackColor=”#F7F7DE” />
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61<SelectedRowStyle BackColor=”#CE5D5A” Font-Bold=”True” ForeColor=”White” />
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63<PagerStyle BackColor=”#F7F7DE” ForeColor=”Black” HorizontalAlign=”Right” />
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65<HeaderStyle BackColor=”#6B696B” Font-Bold=”True” ForeColor=”White” />
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67<AlternatingRowStyle BackColor=”White” />
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69</asp:GridView>
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71
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73<asp:SqlDataSource ID=”SqlDataSource1″ runat=”server” ConnectionString=”<%$ ConnectionStrings:ContactsConnectionString1 %>”
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75DeleteCommand=”DELETE FROM [ContactPhone] WHERE [ContactID] = @ContactID” InsertCommand=”INSERT INTO [ContactPhone] ([FName], [LName], [ContactPhone]) VALUES (@FName, @LName, @ContactPhone)”
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77ProviderName=”<%$ ConnectionStrings:ContactsConnectionString1.ProviderName %>”
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79SelectCommand=”SELECT [ContactID], [FName], [LName], [ContactPhone] FROM [ContactPhone]”
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81UpdateCommand=”UPDATE [ContactPhone] SET [FName] = @FName, [LName] = @LName, [ContactPhone] = @ContactPhone WHERE [ContactID] = @ContactID”>
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83<InsertParameters>
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85<asp:Parameter Name=”FName” Type=”String” />
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87<asp:Parameter Name=”LName” Type=”String” />
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89<asp:Parameter Name=”ContactPhone” Type=”String” />
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91</InsertParameters>
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93<UpdateParameters>
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95<asp:Parameter Name=”FName” Type=”String” />
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97<asp:Parameter Name=”LName” Type=”String” />
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99<asp:Parameter Name=”ContactPhone” Type=”String” />
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101<asp:Parameter Name=”ContactID” Type=”Int32″ />
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103</UpdateParameters>
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105<DeleteParameters>
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107<asp:Parameter Name=”ContactID” Type=”Int32″ />
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109</DeleteParameters>
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111</asp:SqlDataSource>
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113
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115<br />
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117</div>
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119</form>
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121</body>
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123</html>
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ExcelExport.aspx.cs
1using System;
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3using System.Data;
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5using System.Configuration;
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7using System.Collections;
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9using System.Web;
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11using System.Web.Security;
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13using System.Web.UI;
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15using System.Web.UI.WebControls;
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17using System.Web.UI.WebControls.WebParts;
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19using System.Web.UI.HtmlControls;
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21using System.Text;
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23using System.IO;
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25
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27public partial class DeleteConfirm : System.Web.UI.Page
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29{
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31
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33 protected void Page_Load(object sender, EventArgs e)
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35 {
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37 }
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39
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41 protected void Button1_Click(object sender, EventArgs e)
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43 {
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45 //Export the GridView to Excel
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47 PrepareGridViewForExport(GridView1);
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49 ExportGridView();
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51 }
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53
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55 private void ExportGridView()
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57 {
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59 string attachment = “attachment; filename=Contacts.xls”;
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61 Response.ClearContent();
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63 Response.AddHeader(“content-disposition”, attachment);
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65 Response.ContentType = “application/ms-excel”;
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67 StringWriter sw = new StringWriter();
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69 HtmlTextWriter htw = new HtmlTextWriter(sw);
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71 GridView1.RenderControl(htw);
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73 Response.Write(sw.ToString());
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75 Response.End();
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77 }
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79
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81 public override void VerifyRenderingInServerForm(Control control)
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83 {
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85 }
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87
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89 private void PrepareGridViewForExport(Control gv)
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91 {
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93 LinkButton lb = new LinkButton();
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95 Literal l = new Literal();
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97 string name = String.Empty;
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99 for (int i = 0; i < gv.Controls.Count; i++)
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101 {
102
103 if (gv.Controls[i].GetType() == typeof(LinkButton))
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105 {
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107 l.Text = (gv.Controls[i] as LinkButton).Text;
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109 gv.Controls.Remove(gv.Controls[i]);
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111 gv.Controls.AddAt(i, l);
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113 }
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115 else if (gv.Controls[i].GetType() == typeof(DropDownList))
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117 {
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119 l.Text = (gv.Controls[i] as DropDownList).SelectedItem.Text;
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121 gv.Controls.Remove(gv.Controls[i]);
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123 gv.Controls.AddAt(i, l);
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125 }
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127 else if (gv.Controls[i].GetType() == typeof(CheckBox))
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129 {
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131 l.Text = (gv.Controls[i] as CheckBox).Checked ? “True” : “False”;
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133 gv.Controls.Remove(gv.Controls[i]);
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135 gv.Controls.AddAt(i, l);
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137 }
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139 if (gv.Controls[i].HasControls())
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141 {
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143 PrepareGridViewForExport(gv.Controls[i]);
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145 }
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147 }
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149 }
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151}
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Implementation Options:
通常情况,在输出函数中开发人员都会面临一个错误,典型的就是”RegisterForEventValidation can only be called during Render();”
访问者通常会在评论中提出一些好的建议.我特别要强调的是开发者需要重写VerifyRenderingInServerForm方法,该方法描述如下:
- Step 1:实现导出功能的上述功能.
- Step 2:重写一个VerifyRenderingInServerForm的空方法.
- Step 3:修改ExportGridView函数,在绿色高亮代码部创建HtmlForm【原句为:The code highlighted in green creates and HtmlForm on the fly,在翻译HtmlForm on the fly时遇到了一些困难,故on the fly未翻译,请各位高手指教】,在导出girdview之前,添加gridview 到新的form并且render它(取代原来的render实现)
private void ExportGridView()
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{
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5 string attachment = “attachment; filename=Contacts.xls”;
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7 Response.ClearContent();
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9 Response.AddHeader(“content-disposition”, attachment);
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11 Response.ContentType = “application/ms-excel”;
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13 StringWriter sw = new StringWriter();
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15 HtmlTextWriter htw = new HtmlTextWriter(sw);
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17
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19 // Create a form to contain the grid
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21 HtmlForm frm = new HtmlForm();
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23 GridView1.Parent.Controls.Add(frm);
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25 frm.Attributes[“runat”] = “server”;
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27 frm.Controls.Add(GridView1);
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29
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31 frm.RenderControl(htw);
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33 //GridView1.RenderControl(htw);
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35 Response.Write(sw.ToString());
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37 Response.End();
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39}
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这样实施有个优势,就是可将其设置为复用代码类库,不用每次去复写基类的方法.
Note to readers:
Thank you for your comments and feedback! Happy coding!!!
ASP.Net 2.0: Export GridView to Excel – Part II
该文中将会在导出Excel 时GridView引入Hyperlink列,以至于需要使用更多的反射来重新设计原来的逻辑.
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