Problem with data GridView C#

  private void dgCountryZone_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
        {
            if (dgCountryZone.Columns[this.dgCountryZone.CurrentCell.ColumnIndex].Name.Equals("Destination Code"))
            {
                TextBox txt = e.Control as TextBox;
                txt.Multiline = false;
                txt.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
                txt.AutoCompleteSource = AutoCompleteSource.CustomSource;
                txt.AutoCompleteCustomSource = colCountryListCodeCheck;
            }
        } 
 
*********************************************************************
 
private void dgCountryZone_CellEndEdit(object sender, DataGridViewCellEventArgs e)
        {
            Int32 RowCounter;
            Int32 DuplicateCounter;
            IDataReader idrCountryName;
            DuplicateCounter = 0;
 
            if (dgCountryZone.Columns[e.ColumnIndex].Name == "Destination Code")
            {
                if (Convert.ToString(dgCountryZone.Rows[e.RowIndex].Cells[e.ColumnIndex].Value) != "")
                {
                    for (RowCounter = 0; RowCounter <= dgCountryZone.Rows.Count - 1; RowCounter++)
                    {
                        if (Convert.ToString(dgCountryZone.Rows[RowCounter].Cells[e.ColumnIndex].Value) == Convert.ToString(dgCountryZone.Rows[e.RowIndex].Cells[e.ColumnIndex].Value))
                        {
                            DuplicateCounter++;
                        }
                    }
                    if (DuplicateCounter > 1)
                    {
                        dgCountryZone.Rows[e.RowIndex].Cells[e.ColumnIndex].Value = "";
                        MessageBox.Show(MessageResource.DuplicateRecord, "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        dgCountryZone.CurrentCell = dgCountryZone[e.ColumnIndex, e.RowIndex];
                        return;
                    }
                    else
                    {
                        DataAccessLayer daobj = new DataAccessLayer();
                        UserDataType.CountryParam CParam = new UserDataType.CountryParam();
                        CParam.szCountryCode = Convert.ToString(dgCountryZone.Rows[e.RowIndex].Cells[e.ColumnIndex].Value);
                        dgCountryZone.Rows[e.RowIndex].Cells[e.ColumnIndex + 1].Value = "";
                        idrCountryName = daobj.GetHelpCountryName(CParam);
                        while (idrCountryName.Read())
                            dgCountryZone.Rows[e.RowIndex].Cells[e.ColumnIndex + 1].Value = idrCountryName.GetString(0);
                        if (Convert.ToString(dgCountryZone.Rows[e.RowIndex].Cells[e.ColumnIndex + 1].Value) != "")
                        {
                            dgCountryZone.CurrentCell = dgCountryZone[e.ColumnIndex + 1, e.RowIndex];
                            return;
                        }
                        else
                        {
                            MessageBox.Show(MessageResource.CodeNotFound, "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
                            dgCountryZone.CurrentCell = dgCountryZone[e.ColumnIndex, e.RowIndex];
                            return;
                        }
                    }
                }
                else
                {
                    MessageBox.Show(MessageResource.BlankField, "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    dgCountryZone.CurrentCell = dgCountryZone[e.ColumnIndex, e.RowIndex];
                    return;
                }
            }
            if (dgCountryZone.Columns[e.ColumnIndex].Name == "Per CWB/KG")
            {
                if (Convert.ToString(dgCountryZone.Rows[e.RowIndex].Cells[e.ColumnIndex].Value) != "")
                {
                    if (Convert.ToString(dgCountryZone.Rows[e.RowIndex].Cells[e.ColumnIndex].Value).ToUpper() != "K" && Convert.ToString(dgCountryZone.Rows[e.RowIndex].Cells[e.ColumnIndex].Value).ToUpper() != "W")
                    {
                        MessageBox.Show("Please select [W for per CWB] and [K for KG]", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        dgCountryZone.CurrentCell = dgCountryZone[e.ColumnIndex, e.RowIndex];
                        return;
                    }
                }
                else
                {
                    MessageBox.Show(MessageResource.BlankField, "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    dgCountryZone.CurrentCell = dgCountryZone[e.ColumnIndex, e.RowIndex];
                    return;
                }
            }
        }

                                              

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