我想根据组合框选择获取或设置数据到DataGridView的每个单元格

请找到我的代码，我需要知道组合框选择和datagridview之间的关系。基本上，如果我设置区域选择只显示与区域相关的内容而不是像现在这样显示整个数据库。谢谢。

        private void RTUModification_Load(object sender, EventArgs e) {
        //Select cell where checkbox to be display
        Rectangle rect = this.rtumodDGV1.GetCellDisplayRectangle(0, -1, true);   
        chkbox.Size = new Size(18, 18);
        //set position of header checkbox where to places
        rect.Offset(4, 2);
        chkbox.Location = rect.Location;
        chkbox.CheckedChanged += rtucheckBoxCheckChanged;
        //Add CheckBox control to datagridView
        this.rtumodDGV1.Controls.Add(chkbox);
        // Create new DataTable instance
        dtDataTable = new System.Data.DataTable();
        if (null == dtDataTable)
        {
            MessageBox.Show("Insufficient memory.", "ERROR");
        }
        //load the datable and fill them with value
        strErrorMsg = Utilities.OpenSQLConnection(out m_SqlConn, true, false);   //load normal database
        if (false == string.IsNullOrEmpty(strErrorMsg))
        {
            MessageBox.Show(strErrorMsg, "SQL connection ERROR");
        }
        SqlDataAdapter sqlAdapter = null;
        strSelectCmd = "SELECT Area_ID, StationId, SystemId, CCNumber, LineNumber, RTUNumber, SRTUNumber, Description, SDescription FROM RTU_ADDRESS";
        SqlCommand sqlCmd = new SqlCommand();
        sqlCmd.Connection = m_SqlConn;
        sqlCmd.CommandText = strSelectCmd;
        sqlAdapter = new SqlDataAdapter();
        sqlAdapter.SelectCommand = sqlCmd;
        strErrorMsg = Utilities.FillDataTable(m_SqlConn, strSelectCmd, dtDataTable);
        if (string.IsNullOrEmpty(strErrorMsg) == false)
        {
            MessageBox.Show("Failed to retrieve information from database.", "ERROR");
            dtDataTable.Dispose();
            Utilities.CloseAndDisposeSQLConnection(m_SqlConn);
        }
        int iRetrievedNoOfRecords = dtDataTable.Rows.Count;
        if (iRetrievedNoOfRecords > 0)
        {
            for (int i = 0; i < iRetrievedNoOfRecords; i++)
                this.rtumodcomboBox.Items.Add((string)dtDataTable.Rows[i]["Area_ID"]);
        }
        strErrorMsg = Utilities.ExecuteSQLCommand(m_SqlConn, strSelectCmd);
        if (string.IsNullOrEmpty(strErrorMsg) == false)
        {
            MessageBox.Show(this, "Error!Loading into RTU datagrid");
        }
        //load the datagridview header
        rtumodDGV1.DataSource = dtDataTable;         
    }

  strSelectCmd = "SELECT Area_ID, StationId, SystemId, CCNumber, LineNumber, RTUNumber, SRTUNumber, Description, SDescription FROM RTU_ADDRESS where Area_ID="+cbxMyCombox.SelectedIndex;