Problem with Two DataDridViews

Hi all,

First I'm going to try to explain my problem.

I have two tables in a SQLEXPRESS database, a company table (opdg) and a contacts table (opdg_cp) which is holding the contacts for a company by company Id (opdg_Id). BTW Id in the company table is the primary key and is Identity, increment 1.

To keep it simple:

Company DataBase

Id        Name

1         HillWood

2         Fergusson

3         van Dyke

Contacts Database

Id         Lastname        opdg_Id

1          Dewalt                1

2          Johnson              1

3          Henderson           3

4          Anderson            2

5          Eastwood            2

So 2 contacts belong to Fergusson, 2 to Hillwood and 1 to van Dyke

I created two datagridviews on one form. On holding the Companies and on holding the contacts. Both datagridviews are able to update, add, and insert records. What I'm trying to do is:

If I walk through the company database in the first datagridview, the second datagridview should show me the contacts for that company because of the opdg_Id cell in the contacts table. Well, I did that, it works well. I will include all code below.

But, I get a problem when I'm scrolling down in the company datagridview and I hit theCurrentRow.IsNewRow event to add a new record. Because at that point there is just at that particular moment no known value in the Idcell of the company table, it's still NULL. At that point I'm using the

datagridview_CurrentCellChanged event to search for matching contacts by C_Id, but the Id cell is NULL so I get an error.

Below the Code. BTW for opening, closing the database I use a separate Class, which I also include below.

This is the Class I'm using

Imports System.Data.SqlClient

Public Class SQLControl
    Dim HostIP = My.Settings.HostIP
    Dim DataBase = My.Settings.Database
    Dim User = My.Settings.User
    Dim Password = My.Settings.Password

    ' CONNECTION
    Public SQLCon As New SqlConnection With {.ConnectionString = "server=" & HostIP & ";User=" & User & ";Pwd=" & Password & ";Database=" & DataBase}
    Public SQLCmd As New SqlCommand

    Public Function HasConnection() As Boolean
        Try
            SQLCon.Open()

            SQLCon.Close()
            Return True
        Catch ex As Exception
            MsgBox(ex.Message)
            Return False
        End Try

    End Function

    ' SQL DATA
    Public SQLDA As SqlDataAdapter
    Public SQLDS As DataSet

    ' QUERY PARAMETERS
    Public Params As New List(Of SqlParameter)

    ' QUERY STATISTICS
    Public RecordCount As Integer
    Public Exception As String


    Public Sub ExecQuery(Query As String)
        Try
            SQLCon.Open()

            ' CREATE SQL COMMAND
            SQLCmd = New SqlCommand(Query, SQLCon)

            ' LOAD PARAMETERS INTO SQL COMMAND
            Params.ForEach(Sub(x) SQLCmd.Parameters.Add(x))

            ' CLEAR PARAMETER LIST
            Params.Clear()

            ' CREATE NEW DATASET AND DATAADAPTER
            SQLDS = New DataSet
            SQLDA = New SqlDataAdapter(SQLCmd)
            RecordCount = SQLDA.Fill(SQLDS)

            SQLCon.Close()

        Catch ex As Exception
            Exception = ex.Message
        End Try

        If SQLCon.State = ConnectionState.Open Then SQLCon.Close()
    End Sub

End Class

Below the code for the Windows form, I deleted as much as code to keep it clear, and the BOLDpart is my problem. BTW I'm from Holland, so I'm trying to explain my problem in English as good as I can.

Imports System.Data.Sql
Imports System.Data.SqlClient

Public Class Opdrachtgevers
    ' TWO NEW INSTANCES FROM SQLCONTROL CLASS
    Private SQL As New SQLControl
    Private SQL1 As New SQLControl
    Public search As String
    ' WHEN FORM IS LOADED
    Private Sub Opdrachtgevers_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        ' EXECUTE QUERY AND POPULATE GRID, (FIRST DATAGRIDVIEW, COMPANY)
        SQL.ExecQuery("select * from opdg")

        ' CALL LOADGRID_OPDG SUBROUTINE (First DataGridView, COMPANY)
        LoadGrid_opdg()

        ' DISABLE SAVE BUTTON
        btn_Opslaan_Opdg.Enabled = False

    End Sub

    ' LOADGRID_OPDG SUBROUTINE
    Private Sub LoadGrid_opdg()

        ' IF DATA IS RETURNED, POPULATE GRID & BUILD UPDATE COMMAND
        If SQL.RecordCount > 0 Then
            Opdg_Grid_View.DataSource = SQL.SQLDS.Tables(0)
            Opdg_Grid_View.Rows(0).Selected = True
            Opdg_Grid_View.Columns("id").Visible = False
            SQL.SQLDA.UpdateCommand = New SqlCommandBuilder(SQL.SQLDA).GetUpdateCommand
        End If
    End Sub

    Private Sub opdg_grid_view_CurrentCellChanged(sender As Object, e As EventArgs) Handles Opdg_Grid_View.CurrentCellChanged

        If Opdg_Grid_View.CurrentCellAddress.X < 0 Or Opdg_Grid_View.CurrentCellAddress.Y < 0 Then Exit Sub
        If Opdg_Grid_View.CurrentRow.IsNewRow Then' THIS IS WHERE I HAVE A PROBLEM. IF A NEW ROW IS DETECTED AND THERE
            ' IS A NULL VALUE IN THE ID CELL, I CAN'T SEARCH THE CONTACTS TABLE,
            ' BECAUSE, THIS IS A NEW COMPANY RECORD, AND NOT SAVED
            ' BUT INSTEAD OF THAT, AFTER FILLING IN THE COMPANY'S RECORD,
            ' IT SHOULD BE POSSIBLE TO GO TO THE SECOND DATAGRIDVIEW TO FILL
            ' IN THE FIRST NEW CONTACT FOR THAT COMPANY.
        Else
            ' GET THE COMPANY'S ID
            search = Opdg_Grid_View.CurrentRow.Cells("id").Value
            'SEARCH FOR THE COMPANY'S CONTACT
            SQL1.ExecQuery("select * from opdg_cp where opdg_id =" & search)
            ' LOAD THE CONTACTS DATAGRIDVIEW
            LoadGrid_opdg_cp()
        End If
        Exit Sub
    End Sub
    Private Sub LoadGrid_opdg_cp()

        ' IF DATA IS RETURNED, POPULATE GRID & BUILD UPDATE COMMAND
        If SQL1.RecordCount > 0 Then

            Opdg_Cp_Grid_View.DataSource = SQL1.SQLDS.Tables(0)
            Opdg_Cp_Grid_View.Rows(0).Selected = True
            Opdg_Cp_Grid_View.Columns("id").Visible = False
            Opdg_Cp_Grid_View.Columns("opdg_id").Visible = False

            SQL1.SQLDA.UpdateCommand = New SqlCommandBuilder(SQL1.SQLDA).GetUpdateCommand
        Else
            Call CType(Opdg_Cp_Grid_View.DataSource, DataTable).Rows.Clear()
        End If
    End Sub

    Private Sub opdg_cp_grid_view_CurrentCellChanged(sender As Object, e As EventArgs) Handles Opdg_Cp_Grid_View.CurrentCellChanged

        If Opdg_Cp_Grid_View.CurrentCellAddress.X < 0 Or Opdg_Grid_View.CurrentCellAddress.Y < 0 Then Exit Sub
        If Opdg_Cp_Grid_View.CurrentRow.IsNewRow Then



        Else
            Dim search = Opdg_Cp_Grid_View.CurrentRow.Cells("id").Value
            SQL1.ExecQuery("select * from opdg_cp where opdg_id =" & search)
            LoadGrid_opdg_cp()
        End If
        Exit Sub
    End Sub


    Private Sub btn_Opslaan_Opdg_Click(sender As Object, e As EventArgs) Handles btn_Opslaan_Opdg.Click
        ' SAVE UPDATES TO THE DATABASE
        SQL.SQLDA.Update(SQL.SQLDS) ' TO DO : ERROR CHECKING, DATA VALIDATION

        ' REFRESH GRID DATA
        LoadGrid_opdg()

        ' DISABLE SAVE BUTTON
        btn_Opslaan_Opdg.Enabled = False
        MsgBox("Gegevens zijn opgeslagen")

    End Sub

    Private Sub Opdg_Grid_View1_CellValueChanged(sender As Object, e As DataGridViewCellEventArgs) Handles Opdg_Grid_View.CellValueChanged
        btn_Opslaan_Opdg.Enabled = True
    End Sub

    Private Sub Opdg_Grid_View1_RowsRemoved(sender As Object, e As DataGridViewRowsRemovedEventArgs) Handles Opdg_Grid_View.RowsRemoved
        btn_Opslaan_Opdg.Enabled = True
    End Sub

    Private Sub Opdrachtgevers_Closing(sender As Object, e As System.ComponentModel.CancelEventArgs) Handles MyBase.Closing
        If Me.WindowState = FormWindowState.Normal Then
            My.Settings.Opdg_Location = Me.Location
            My.Settings.Opdg_Size = Me.Size
        End If
        My.Settings.Opdg_Ws = Me.WindowState
        My.Settings.Save()
    End Sub

    Private Sub btn_Zoek_Opdg_Click(sender As Object, e As EventArgs) Handles btn_Zoek_Opdg.Click
        SQL.ExecQuery("select * from opdg where Bedrijfsnaam like '" & txt_Zoek_Opdg.Text & "%'")

        LoadGrid_opdg()

    End Sub

    Private Sub Btn_Opslaan_Opdg_Cp_Click(sender As Object, e As EventArgs) Handles Btn_Opslaan_Opdg_Cp.Click
Opdg_Cp_Grid_View.CurrentRow.Cells(9).Value = search

        SQL1.SQLDA.Update(SQL1.SQLDS)
        MsgBox("Gegevens zijn opgeslagen")
    End Sub
End Class

So, this is it. In short:

If a new company is added, don't search for the contact, but it should be able to add that contact directly after the company's record is filled in in the first datagridview.

Many thanks for everybody who takes some time to look at this problem.

regards,

Mark Hofand