在线等，导出excel问题，单元格自适用

代码如下：没问题，就是我有个字段太长，显示不美观啊，如何设置宽度自适用？请不吝指教！
看红色部分： private void button1_Click(object sender, EventArgs e)
        {
         DataSet mDSData = new DataSet();
            mDSData.Tables.Add("myTable");            mDSData.Tables["myTable"].Columns.Add("ID");
            mDSData.Tables["myTable"].Columns.Add("Name");
            mDSData.Tables["myTable"].Columns.Add("PassWord");            for (int i = 0; i < 10; i++)
            {
                DataRow dr = mDSData.Tables["myTable"].NewRow();
                dr["ID"] = i;
                dr["Name"] = i;
                dr["PassWord"] = i;
                mDSData.Tables["myTable"].Rows.Add(dr);
            }            SaveFileDialog dialog1 = new SaveFileDialog();
            dialog1.AddExtension = true;
            dialog1.CheckPathExists = true;
            dialog1.Filter = "Excel Workbooks (*.xls) | *.xls";
            dialog1.OverwritePrompt = true;
            dialog1.Title = "Save Excel Formatted Report";
            if (dialog1.ShowDialog() == DialogResult.OK)
            {
                int num2 = 0;
                int num3 = mDSData.Tables[0].Rows.Count + 1;
                int num1 = mDSData.Tables[0].Columns.Count;
                num2 = 0;
                string text1 = dialog1.FileName;
                if (File.Exists(text1))
                {
                    File.Delete(text1);
                }
                StreamWriter writer1 = new StreamWriter(text1, false);
                StreamWriter writer2 = writer1;
                writer2.WriteLine("<?xml version=\"1.0\"?>");
                writer2.WriteLine("<?mso-application progid=\"Excel.Sheet\"?>");
                writer2.WriteLine("<Workbook xmlns=\"urn:schemas-microsoft-com:office:spreadsheet\"");
                writer2.WriteLine(" xmlns:o=\"urn:schemas-microsoft-com:office:office\"");
                writer2.WriteLine(" xmlns:x=\"urn:schemas-microsoft-com:office:excel\"");
                writer2.WriteLine(" xmlns:ss=\"urn:schemas-microsoft-com:office:spreadsheet\"");
                writer2.WriteLine(" xmlns:html=\"http://www.w3.org/TR/REC-html40\">");
                writer2.WriteLine(" <DocumentProperties xmlns=\"urn:schemas-microsoft-com:office:office\">");
                writer2.WriteLine("  <Author>Automated Report Generator Example</Author>");
                writer2.WriteLine(string.Format("  <Created>{0}T{1}Z</Created>", DateTime.Now.ToString("yyyy-mm-dd"), DateTime.Now.ToString("HH:MM:SS")));
                writer2.WriteLine("  <Company>Your Company Here</Company>");
                writer2.WriteLine("  <Version>11.6408</Version>");
                writer2.WriteLine(" </DocumentProperties>");
                writer2.WriteLine(" <ExcelWorkbook xmlns=\"urn:schemas-microsoft-com:office:excel\">");
                writer2.WriteLine("  <WindowHeight>8955</WindowHeight>");
                writer2.WriteLine("  <WindowWidth>11355</WindowWidth>");
                writer2.WriteLine("  <WindowTopX>480</WindowTopX>");
                writer2.WriteLine("  <WindowTopY>15</WindowTopY>");
                writer2.WriteLine("  <ProtectStructure>False</ProtectStructure>");
                writer2.WriteLine("  <ProtectWindows>False</ProtectWindows>");
                writer2.WriteLine(" </ExcelWorkbook>");
                writer2.WriteLine(" <Styles>");
                writer2.WriteLine("  <Style ss:ID=\"Default\" ss:Name=\"Normal\">");
                writer2.WriteLine("   <Alignment ss:Vertical=\"Bottom\"/>");
                writer2.WriteLine("   <Borders/>");
                writer2.WriteLine("   <Font/>");
                writer2.WriteLine("   <Interior/>");
                writer2.WriteLine("   <Protection/>");
                writer2.WriteLine("  </Style>");
                writer2.WriteLine("  <Style ss:ID=\"s21\">");
                writer2.WriteLine("   <Alignment ss:Vertical=\"Bottom\" ss:WrapText=\"1\"/>");
                writer2.WriteLine("  </Style>");
                writer2.WriteLine(" </Styles>");
                writer2.WriteLine(" <Worksheet ss:Name=\"MyReport\">");
                writer2.WriteLine(string.Format("  <Table ss:ExpandedColumnCount=\"{0}\" ss:ExpandedRowCount=\"{1}\" x:FullColumns=\"1\"", num1.ToString(), num3.ToString()));
                writer2.WriteLine("   x:FullRows=\"1\">");
                foreach (DataRow row1 in mDSData.Tables[0].Rows)
                {
                    writer2.WriteLine("<Row>");
                    for (num2 = 0; num2 != num1; num2++)
                    {
                        writer2.Write("<Cell ss:StyleID=\"s21\"><Data ss:Type=\"String\">");                        writer2.Write(row1[num2].ToString());
                        writer2.WriteLine("</Data></Cell>");
                    }
                    writer2.WriteLine("</Row>");
                }
                writer2.WriteLine("  </Table>");
                writer2.WriteLine("  <WorksheetOptions xmlns=\"urn:schemas-microsoft-com:office:excel\">");
                writer2.WriteLine("   <Selected/>");
                writer2.WriteLine("   <Panes>");
                writer2.WriteLine("    <Pane>");
                writer2.WriteLine("     <Number>3</Number>");
                writer2.WriteLine("     <ActiveRow>1</ActiveRow>");
                writer2.WriteLine("    </Pane>");
                writer2.WriteLine("   </Panes>");
                writer2.WriteLine("   <ProtectObjects>False</ProtectObjects>");
                writer2.WriteLine("   <ProtectScenarios>False</ProtectScenarios>");
                writer2.WriteLine("  </WorksheetOptions>");
                writer2.WriteLine(" </Worksheet>");
                writer2.WriteLine(" <Worksheet ss:Name=\"Sheet2\">");
                writer2.WriteLine("  <WorksheetOptions xmlns=\"urn:schemas-microsoft-com:office:excel\">");
                writer2.WriteLine("   <ProtectObjects>False</ProtectObjects>");
                writer2.WriteLine("   <ProtectScenarios>False</ProtectScenarios>");
                writer2.WriteLine("  </WorksheetOptions>");
                writer2.WriteLine(" </Worksheet>");
                writer2.WriteLine(" <Worksheet ss:Name=\"Sheet3\">");
                writer2.WriteLine("  <WorksheetOptions xmlns=\"urn:schemas-microsoft-com:office:excel\">");
                writer2.WriteLine("   <ProtectObjects>False</ProtectObjects>");
                writer2.WriteLine("   <ProtectScenarios>False</ProtectScenarios>");
                writer2.WriteLine("  </WorksheetOptions>");
                writer2.WriteLine(" </Worksheet>");
                writer2.WriteLine("</Workbook>");
                writer2 = null;
                writer1.Close();
                MessageBox.Show("Report Created", "Success", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
            }
        }
红色代码部分我想设置宽度自适用，如何整啊？