获得access列大小

string strConnection = "Provider=Microsoft.Jet.OleDb.4.0;Data Source=" + this.textBox1.Text;
            OleDbConnection clientConnection = new OleDbConnection(strConnection);  //建立ACCESS数据库连接
            clientConnection.Open();

            DataTable SchemaTable = clientConnection.GetOleDbSchemaTable(System.Data.OleDb.OleDbSchemaGuid.Columns,

                                                new object[] { null, null, null, null });
            System.Data.DataRowCollection  drc=SchemaTable.Rows; 
            //int m=0;

          // foreach (DataColumn sd in SchemaTable.Columns)
            //{ MessageBox.Show(sd.ColumnName); }
            FileStream fs = new FileStream(textBox2.Text +  "提取.txt", FileMode.OpenOrCreate, FileAccess.Write);
            StreamWriter sw = new StreamWriter(fs, System.Text.Encoding.GetEncoding("GB2312"));
            sw.Flush();
            sw.BaseStream.Seek(0, SeekOrigin.End);
  foreach(DataRow  dr  in  drc)
  {
      sw.WriteLine(dr.ItemArray[2].ToString() + "," + dr["COLUMN_NAME"] + ","  + dr["data_type"] + "," + dr["DESCRIPTION"].ToString() +","+ dr["numeric_precision"].ToString() + " ," + dr["numeric_scale"]+dr["character_maximum_length"] );