如何将datagridview中的数据导出到Excel中

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms ;
using System.IO;

namespace OutputToExecl
{
public class ExportXLS
{
public ExportXLS()
{

}
public static void ExportDataGridViewToExcel(DataGridView dataGridview1)
{
SaveFileDialog saveFileDialog = new SaveFileDialog();
saveFileDialog.Filter = "Execl files (*.xls)|*.xls";
saveFileDialog.FilterIndex = 0;
saveFileDialog.RestoreDirectory = true;
saveFileDialog.CreatePrompt = true;
saveFileDialog.Title = "导出Excel文件到";

saveFileDialog.ShowDialog();

Stream myStream;
myStream = saveFileDialog.OpenFile();
StreamWriter sw = new StreamWriter(myStream, System.Text.Encoding.GetEncoding("gb2312"));
string str = "";
try
{
//写标题
for (int i = 0; i < dataGridview1.ColumnCount; i++)
{
if (i > 0)
{
str += "\t";
}
str += dataGridview1.Columns[i].HeaderText;
}

sw.WriteLine(str);
//写内容
for (int j = 0; j < dataGridview1.Rows.Count; j++)
{
string tempStr = "";
for (int k = 0; k < dataGridview1.Columns.Count; k++)
{
if (k > 0)
{
tempStr += "\t";
}
tempStr += dataGridview1.Rows[j].Cells[k].Value.ToString();
}
sw.WriteLine(tempStr);
}
sw.Close();
myStream.Close();
}
catch (Exception e)
{
MessageBox.Show(e.ToString());
}
finally
{
sw.Close();
myStream.Close();
}
}

}
}