Getting Value Member of Combobox

[riechan]

Let's say I bound a combobox to a datatable. How can I get the valuemember of the currently selected item in the combobox (for example, when I have to save the data, I need to get the valuemember - PatronTypePK - of the currently selected item in cmbPatronType)? And can anyone check if I made the code correctly or if there are any programming practice errors/inconsistencies? I wanted to fetch two tables into a single dataset (Patron, PatronType). Do I have to make a datatable for each, or can I simply use the dataadapter?

Private Sub frmPatronManager_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        'MUST FIRST CHECK IF THERE ARE ANY RECORDS IN THE PATRON TYPE MANAGER

        dbConn.ConnectionString = "Integrated Security=SSPI; Initial Catalog=CBIS; Persist Security Info=False;"
        dbConn.Open()

        'initially populate the dataset
        dbAdpPatron = New SqlClient.SqlDataAdapter("SELECT * FROM Patron", dbConn)
        dbDsetPatron = New DataSet
        dbAdpPatron.Fill(dbDsetPatron, "Patron")

        'display data from the database into the text fields and datagrid
        If dbDsetPatron.Tables(0).Rows.Count > 0 Then
            FillFields()
            btnFirst.Enabled = False
            btnPrevious.Enabled = False

            dgPatron.DataSource = dbDsetPatron
            dgPatron.DataMember = "Patron"

            'populate the adapter of patrontypes that will fill the combobox
            dbAdpPatronType = New SqlClient.SqlDataAdapter("SELECT PatronTypeName FROM PatronType", dbConn)
            dbDsetPatron = New DataSet
            dbAdpPatron.Fill(dbDsetPatron, "PatronType")

            With cmbPatronType
                .DataSource = dbDsetPatron.Tables("PatronType")
                .DisplayMember = "PatronTypeName"
                .ValueMember = "PatronTypeDesc"
                .SelectedIndex = 0
            End With

        ElseIf dbDsetPatron.Tables(0).Rows.Count = 0 Then
            MsgBox("There are no available Patron records. Click the" & vbCrLf & "[Register] button to start adding records.", MsgBoxStyle.Information, "No Available Records")
        End If

        're-initilize the flags as FALSE
        addflag = False
        editflag = False

        dbConn.Close()
    End Sub

The code for btnSave:

Dim Validated As Boolean = False

        Dim dbInsert As New SqlCommand("INSERT INTO Patron(PatronNumber, FirstName, LastName, StreetAddress, City, " & _
                "ContactNumber, EmailAddress, Remarks, ViolationCount, Status) VALUES (@insPatronNumber, @insFirstName, @insLastName," & _
                "@insStreetAddress, @insCity, @insContactNumber, @insEmailAddress, @insRemarks, @insViolationCount, @Status)", dbConn)

        'fetch the valuemember of the currently selected item in cmbPatronType
        PatronNumber = cmbPatronType.ValueMember
        MsgBox(PatronNumber)
        Exit Sub

        FirstName = Trim(txtFirstName.Text)
        LastName = Trim(txtLastName.Text)
        StreetAddress = Trim(txtStreetAddress.Text)
        City = Trim(txtCity.Text)
        ContactNumber = Trim(txtContactNumber.Text)
        EmailAddress = Trim(txtEmailAddress.Text)
        Remarks = Trim(txtRemarks.Text)
        ViolationCount = Val(txtViolationCount.Text)

        dbConn.Open()
        dbAdpPatron = New SqlClient.SqlDataAdapter("SELECT * FROM Patron", dbConn)
        dbDsetPatron = New DataSet
        dbAdpPatron.Fill(dbDsetPatron, "Patron")

        'sql insert cmd parameter declaration
        dbAdpPatron.InsertCommand = dbInsert
        With dbInsert
            .Connection = dbConn

            .Parameters.Add(New SqlParameter("@insPatronNumber", SqlDbType.VarChar, 15, "PatronNumber"))
            .Parameters.Add(New SqlParameter("@insFirstName", SqlDbType.VarChar, 40, "FirstName"))
            .Parameters.Add(New SqlParameter("@insLastName", SqlDbType.VarChar, 40, "LastName"))
            .Parameters.Add(New SqlParameter("@insStreetAddress", SqlDbType.VarChar, 60, "StreetAddress"))
            .Parameters.Add(New SqlParameter("@insCity", SqlDbType.VarChar, 30, "City"))
            .Parameters.Add(New SqlParameter("@insContactNumber", SqlDbType.VarChar, 20, "ContactNumber"))
            .Parameters.Add(New SqlParameter("@insEmailAddress", SqlDbType.VarChar, 40, "EmailAddress"))
            .Parameters.Add(New SqlParameter("@insRemarks", SqlDbType.VarChar, 50, "Remarks"))
            .Parameters.Add(New SqlParameter("@insViolationCount", SqlDbType.Int, 4, "ViolationCount"))
            .Parameters.Add(New SqlParameter("@insStatus", SqlDbType.VarChar, 10, "Status"))
        End With

        'check if values entered are valid
        Validated = Validate(FirstName, LastName, StreetAddress, City, ContactNumber, EmailAddress, Remarks, ViolationCount)

        If Validated = True Then

            If addflag = True Then
                'add clause

                Try
                    PatronNumber = Str(Date.Now.Year) & Str(Date.Now.Month) & Str(Date.Now.Day) & Str(Date.Now.Hour) & Str(Date.Now.Minute) & Str(Date.Now.Second)
                    Status = "Authorized"

                    dr = dbDsetPatron.Tables(0).NewRow()
                    dr("FirstName") = FirstName
                    dr("LastName") = LastName
                    dr("StreetAddress") = StreetAddress
                    dr("City") = City
                    dr("ContactNumber") = ContactNumber
                    dr("EmailAddress") = EmailAddress
                    dr("Remarks") = Remarks
                    dr("ViolationCount") = ViolationCount
                    dr("Status") = Status

                    dbDsetPatron.Tables(0).Rows.Add(dr)
                    dbAdpPatron.Update(dbDsetPatron.Tables("Patron"))
                    dbDsetPatron.AcceptChanges()

                    dbDsetPatron.Clear()
                    dbAdpPatron.SelectCommand.CommandText = "SELECT * FROM Patron"
                    dbAdpPatron.Fill(dbDsetPatron, "Patron")

                    'refresh the data on the datagrid
                    dgPatron.DataSource = dbDsetPatron
                    dgPatron.DataMember = "Patron"

                    CurIndex = dbDsetPatron.Tables(0).Rows.Count - 1
                    FillFields()

                    MsgBox(FirstName & " " & LastName & " registered.", MsgBoxStyle.Information, "Patron Registered")
                    disableFields()
                    addflag = False

                Catch parameter As System.Data.SqlClient.SqlException
                    Console.WriteLine(parameter.StackTrace)
                    MsgBox(parameter.ToString)
                Catch invalidparameter As InvalidOperationException
                    MessageBox.Show(invalidparameter.Message)
                End Try
...