DataGrid 导出到 Excel 的帮助类

// =============================================================================== // // 从 DataGrid 或数据源中导出数据到 Excel 并提示下载的帮助类。 // // Author: Roger Chen (木野狐) // Date: 2005-1-27 // Version: 1.22 // History: // v1.00 使用静态方法的形式实现该类，提供多种重载方式。 // v1.01 添加了对 DevExpress.Web.ASPxGrid.ASPxGrid 的直接导出支持。 // v1.20 改写为实体类。 减少了重复代码。 // v1.21 2005-2-1 // 修改了一个构造函数的重载形式中异常检测的代码。延迟到 Export() 方法。 // v1.22 2005-2-3 // 1. 修正了 Export() 方法中缺少 _titles != null 判断的 bug. // 2. 修正了长的数字被 Excel 自动转换为科学计数法的毛病。 // (修改的办法来自 http://dotnet.aspx.cc ) // // =============================================================================== namespace RChen.Demos {
using System;
using System.IO;
using System.Data;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Text;
using System.Globalization;
using System.Collections;
using DevExpress.Web.ASPxGrid;

public class ExcelHelper {
#region Fields

string _fileName;
DataTable _dataSource;
string [] _titles = null ;
string [] _fields = null ;
int _maxRecords = 1000 ;

#endregion

#region Properties

///
/// 限制输出到 Excel 的最大记录数。超出则抛出异常
/// public int MaxRecords {
set { _maxRecords = value; }
get { return _maxRecords; }
}

///
/// 输出到浏览器的 Excel 文件名
/// public string FileName {
set { _fileName = value; }
get { return _fileName; }
}

#endregion

#region .ctor

///
/// 构造函数
///
/// 要输出到 Excel 的列标题的数组
/// 要输出到 Excel 的字段名称数组
/// 数据源 public ExcelHelper( string [] titles, string [] fields, DataTable dataSource): this (titles, dataSource) {
if (fields == null || fields.Length == 0 )
throw new ArgumentNullException( " fields " );

if (titles.Length != fields.Length)
throw new ArgumentException( " titles.Length != fields.Length " , " fields " );

_fields = fields;
}

///
/// 构造函数
///
/// 要输出到 Excel 的列标题的数组
/// 数据源 public ExcelHelper( string [] titles, DataTable dataSource): this (dataSource) {
if (titles == null || titles.Length == 0 )
throw new ArgumentNullException( " titles " );
// if (titles.Length != dataSource.Columns.Count)
// throw new ArgumentException("titles.Length != dataSource.Columns.Count", "dataSource");
_titles = titles;
}

///
/// 构造函数
///
/// 数据源 public ExcelHelper(DataTable dataSource) {
if (dataSource == null )
throw new ArgumentNullException( " dataSource " );
// maybe more checks needed here (IEnumerable, IList, IListSource, ) ???
// 很难判断，先简单的使用 DataTable
_dataSource = dataSource;
}

public ExcelHelper() {}

#endregion

#region public Methods

///
/// 导出到 Excel 并提示下载
///
/// DataGrid public void Export(DataGrid dg) {
if (dg == null )
throw new ArgumentNullException( " dg " );
if (dg.AllowPaging || dg.PageCount > 1 )
throw new ArgumentException( " paged DataGrid can't be exported. " , " dg " );

// 添加标题样式 dg.HeaderStyle.Font.Bold = true ;
dg.HeaderStyle.BackColor = System.Drawing.Color.LightGray;

RenderExcel(dg);
}

///
/// 导出到 Excel 并提示下载
///
/// ASPxGrid public void Export(DevExpress.Web.ASPxGrid.ASPxGrid xgrid) {
if (xgrid == null )
throw new ArgumentNullException( " xgrid " );
if (xgrid.PageCount > 1 )
throw new ArgumentException( " paged xgird not can't be exported. " , " xgrid " );

// 添加标题样式 xgrid.HeaderStyle.Font.Bold = true ;
xgrid.HeaderStyle.BackColor = System.Drawing.Color.LightGray;

RenderExcel(xgrid);
}

///
/// 导出到 Excel 并提示下载
/// public void Export() {
if (_dataSource == null )
throw new Exception( " 数据源尚未初始化 " );

if (_fields == null && _titles != null && _titles.Length != _dataSource.Columns.Count)
throw new Exception( " _titles.Length != _dataSource.Columns.Count " );

if (_dataSource.Rows.Count > _maxRecords)
throw new Exception( " 导出数据条数超过限制。请设置 MaxRecords 属性以定义导出的最多记录数。 " );

DataGrid dg = new DataGrid();
dg.DataSource = _dataSource;

if (_titles == null ) {
dg.AutoGenerateColumns = true ;
}
else {
dg.AutoGenerateColumns = false ;
int cnt = _titles.Length;

System.Web.UI.WebControls.BoundColumn col;

if (_fields == null ) {
for ( int i = 0 ; i < cnt; i ++ ) {
col = new System.Web.UI.WebControls.BoundColumn();
col.HeaderText = _titles[i];
col.DataField = _dataSource.Columns[i].ColumnName;
dg.Columns.Add(col);
}
}
else {
for ( int i = 0 ; i < cnt; i ++ ) {
col = new System.Web.UI.WebControls.BoundColumn();
col.HeaderText = _titles[i];
col.DataField = _fields[i];
dg.Columns.Add(col);
}
}
}

// 添加标题样式 dg.HeaderStyle.Font.Bold = true ;
dg.HeaderStyle.BackColor = System.Drawing.Color.LightGray;
dg.ItemDataBound += new DataGridItemEventHandler(DataGridItemDataBound);

dg.DataBind();
RenderExcel(dg);
}

#endregion

#region private Methods

private void RenderExcel(Control c) {
// 确保有一个合法的输出文件名 if (_fileName == null || _fileName == string .Empty || ! (_fileName.ToLower().EndsWith( " .xls " )))
_fileName = GetRandomFileName();

HttpResponse response = HttpContext.Current.Response;

response.Charset = " GB2312 " ;
response.ContentEncoding = Encoding.GetEncoding( " GB2312 " );
response.ContentType = " application/ms-excel/msword " ;
response.AppendHeader( " Content-Disposition " , " attachment;filename= " +
HttpUtility.UrlEncode(_fileName));

CultureInfo cult = new CultureInfo( " zh-CN " , true );
StringWriter sw = new StringWriter(cult);
HtmlTextWriter writer = new HtmlTextWriter(sw);

writer.WriteLine( " "Content-Type" content="text/html;charset=GB2312">");

DataGrid dg = c as DataGrid;

if (dg != null) {
dg.RenderControl(writer);
}
else {
ASPxGrid xgrid = c as ASPxGrid;

if (xgrid != null)
xgrid.RenderControl(writer);
else
throw new ArgumentException("only supports DataGrid or ASPxGrid.", "c");
}
c.Dispose();

response.Write(sw.ToString());
response.End();
}


///
/// 得到一个随意的文件名
///
/// private string GetRandomFileName() {
Random rnd = new Random((int) (DateTime.Now.Ticks));
string s = rnd.Next(Int32.MaxValue).ToString();
return DateTime.Now.ToShortDateString() + "_" + s + ".xls";
}

private void DataGridItemDataBound(object sender, System.Web.UI.WebControls.DataGridItemEventArgs e) {
if(e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) {
e.Item.Attributes.Add("style", "vnd.ms-excel.numberformat:@");
//e.Item.Cells[3].Attributes.Add("style", "vnd.ms-excel.numberformat:￥#,###.00"); }
}

#endregion
}
} [@more@]

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转载于:http://blog.itpub.net/631872/viewspace-905396/