C# 由DataGridView导出到Excel

private void buttonToExcel_Click (object sender , EventArgs e )
{

    SaveFileDialog saveFileDialog = new SaveFileDialog ();
    saveFileDialog . Filter = "Execl files (*.xls)|*.xls" ;
    saveFileDialog . FilterIndex = 0 ;
    saveFileDialog . RestoreDirectory = true ;
    saveFileDialog . CreatePrompt = true ;
    saveFileDialog . Title = "Export Excel File To" ;
    saveFileDialog . ShowDialog ();
    Stream myStream ;
    myStream = saveFileDialog . OpenFile ();
    StreamWriter sw = new StreamWriter (myStream , System . Text . Encoding . GetEncoding (- 0 ));
    string str = "" ;
    try
    {
        //写标题
        for (int i = 0 ; i < this . dataGridView3 . ColumnCount ; i ++)
        {
            if (i > 0 )
            {
                str += "/t" ;
            }

            str += this . dataGridView3 . Columns [ i ]. HeaderText ;
        }
        sw . WriteLine (str );
        //写内容
        for (int j = 0 ; j < this . dataGridView3 . Rows . Count ; j ++)
        {
            string tempStr = "" ;
            for (int k = 0 ; k < this . dataGridView3 . Columns . Count ; k ++)
            {
                if (k > 0 )
                {
                    tempStr += "/t" ;
                }
                tempStr += this . dataGridView3 . Rows [ j ]. Cells [ k ]. Value + "" ;
            }
            sw . WriteLine (tempStr );
        }

        sw . Close ();
        myStream . Close ();
    }
    catch (Exception ex )
    {
        MessageBox . Show (ex . ToString ());
    }

    finally
    {
        sw . Close ();
        myStream . Close ();
    }     
    MessageBox . Show ("OK" );
}