Select specific columns and store it to arraylist

public void LoadExcelFields(string strConn)
       {
           try
           {
               parameters.currSheet = cboSelectWorksheet.Text;
               //sheetName = cboSelectWorksheet.Text;
               fileName = txtFileName.Text;

               if (parameters.currSheet != "")
               {
                   OleDbConnection newConn = new OleDbConnection(strConn);
                   newConn.Open();

                   OleDbCommand cmd = newConn.CreateCommand();
                   cmd.CommandText = "SELECT * FROM [" + sheetName + "]";


                   dtReader = cmd.ExecuteReader();
                   if (dtReader.Read())
                   {
                       for (int x = 0; x < dtReader.FieldCount; x++)
                       {
                           lstboxExcelFields.Items.Add(dtReader.GetName(x));
                       }
                   }
                   dtReader.Close();
                   cmd.Dispose();
                   newConn.Close();
               }
           }
           catch (Exception ex)
           {
               MessageBox.Show(ex.Message);
           }
       }