从DataSet 导出到Excel(是DataSet中的每个DataTable对应每个Sheet)

先来主要代码：

public static void DataTableToExcel(DataSet dt, string Filename)
{
SaveToFile(ToExcel(dt), Filename);
}

从上往下哈↓↓↓↓↓↓↓↓↓↓↓↓

private static void SaveToFile(MemoryStream ms, string fileName)
{
using (FileStream fs = new FileStream(fileName, FileMode.Create, FileAccess.Write))
{
byte[] data = ms.ToArray();

fs.Write(data, 0, data.Length);
fs.Flush();

data = null;
}
}

使用NPOI来操作Excel:

/// <summary>
/// dataset To Excel
/// </summary>
/// <param name="ds"></param>
/// <returns></returns>
private static MemoryStream ToExcel(DataSet ds)
{
MemoryStream ms = new MemoryStream();
IWorkbook workbook = new HSSFWorkbook();
foreach (DataTable table in ds.Tables)
{
using (table)
{
ISheet sheet = workbook.CreateSheet(table.TableName);
IRow headerRow = sheet.CreateRow(0);

//handling header.
foreach (DataColumn column in table.Columns)
headerRow.CreateCell(column.Ordinal).SetCellValue(column.Caption);//If Caption not set, returns the ColumnName value

//handling value.
int rowIndex = 1;

foreach (DataRow row in table.Rows)
{
IRow dataRow = sheet.CreateRow(rowIndex);

foreach (DataColumn column in table.Columns)
{
dataRow.CreateCell(column.Ordinal).SetCellValue(row[column].ToString());
}

rowIndex++;
}
}

workbook.Write(ms);
ms.Flush();
ms.Position = 0;
}
return ms;
}

最后是调用的方法，也就是入口：

private void Button5_Click(object sender, EventArgs e)
{
SaveFileDialog opf = new SaveFileDialog();
DataSet ds = new DataSet();
DataTable dt = new DataTable();
dt.Columns.Add("编号");   //"编号"
dt.Columns.Add("品名");   //"品名"
dt.Columns.Add("规格");   //"规格"
dt.Columns.Add("单位");   //"单位"
dt.Columns.Add("申请数量");   //"申请数量
dt.Columns.Add("描述");   //"描述"
dt.TableName = "sheet1";
ds.Tables.Add(dt.Copy());
dt.TableName = "sheet2";
ds.Tables.Add(dt.Copy());
dt.TableName = "sheet3";
ds.Tables.Add(dt.Copy());
opf.Filter = "Excel93-07文件（*.xls）|*.xls";
if (DialogResult.OK.Equals(opf.ShowDialog()))
{
string localfilepath = opf.FileName.ToString();
string fileNameExt = localfilepath.Substring(localfilepath.LastIndexOf("\\") + 1); //获取文件名，不带路径
string[] names = fileNameExt.Split('.');
string FilePath = localfilepath.Substring(0, localfilepath.LastIndexOf("\\"));
string newFileName = FilePath + "\\" + names[0] + "_" + string.Format("{0:yyyy-MM-dd}", DateTime.Now) + "." + names[1];     //fileNameExt   DateTime.Now.ToString("yyyyMMdd")
RenderToExcel.DataTableToExcel(ds, newFileName);
MessageBox.Show( "导出完成！", "提示");
}
}

意思就是这个意思，顺带把引用也贴上：

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using NPOI.XSSF.UserModel;
using ICSharpCode.SharpZipLib.Core;

这个四个引用，缺一不可，关于NPOI大家自行百度



导入以上四个引用即可。