//該程式碼我自己測過沒問題，有問題聯絡我，大家一起交流
public void DSToExcel(DataSet ds, string strTitle)
        {
            SaveFileDialog saveFileDialog = new SaveFileDialog();
            saveFileDialog.Filter = "Excel files (*.xls)|*.xls";
            saveFileDialog.FilterIndex = 0;
            saveFileDialog.RestoreDirectory = true;
            saveFileDialog.CreatePrompt = false;
            saveFileDialog.FileName = strTitle + ".xls";
            if (saveFileDialog.ShowDialog() == DialogResult.Cancel) 
            //匯出時，點選【取消】按鈕
            {
                return;
            }
            Stream myStream = saveFileDialog.OpenFile();
            StreamWriter sw = new StreamWriter(myStream, 　　　　　　System.Text.Encoding.GetEncoding(-0));
            string strHeaderText = "";
            try
            {
                //寫標題
                for (int i = 0; i < ds.Tables[0].Columns.Count; i++)
                {
                    if (i > 0)
                    {
                        strHeaderText += "\t";
                    }
                    strHeaderText += ds.Tables[0].Columns[i].ToString();
                }
                sw.WriteLine(strHeaderText);
                //寫內容
                string strItemValue = "";
                for (int j = 0; j < ds.Tables[0].Rows.Count; j++)
                {
                    strItemValue = "";
                    for (int k = 0; k < ds.Tables[0].Columns.Count; k++)
                    {
                        if (k > 0)
                        {
                            strItemValue += "\t";
                        }
                        strItemValue += ds.Tables[0].Rows[j][k].ToString();
                    }
            sw.WriteLine(strItemValue); //把dgv的每一行的資訊寫為sw的每一行
                }
           }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "軟體提示");
                throw ex;
            }
            finally
            {
                sw.Close();
                myStream.Close();
            }
        }