[RESOLVED] Refresh contents of databound combobox

[riechan]

I have a combo box that's filled from a query in the database. If I add a field to the database, the new field won't show up in the form until I close it and reopen it.

So, how do I refresh the contents of that combo box?

I bound the data onto the combo box like this:

            dbConn.Open()
            dbAdpBook = New SqlClient.SqlDataAdapter("SELECT * FROM Publisher", dbConn)
            dbDsetBook = New DataSet
            dbAdpBook.Fill(dbDsetBook, "Publisher")
            dbConn.Close()
            If dbDsetBook.Tables("Publisher").Rows.Count > 0 Then
                With cmbAuthor
                    .DisplayMember = "PublisherName"
                    .ValueMember = "PublisherID"
                    .DataSource = dbDsetBook.Tables("Publisher")
                End With
            End If

I tried copying the same code to the cmbAuthor's Click event, and it gave me this error:

Cannot bind to the new value member. Parameter name: value

and points to the .ValueMember = "PublisherID" line of code.

[stanav]

When you insert a new record to your database, instead of inserting it directly, you can add a new datarow to the datatable and then update that datatable to your database. If you choose to go this route, there's no need to "refresh" the combobox's datasource. However, if you choose to leave it the way it is now, you will need to re-query your database. You don't ned to rebind the datatable to your combobox though. Some thing like this will do:

Private Sub UpdatecmbAuthorDataSource()
   Dim table As DataTable = DirectCast(cmbAuthor.DataSource, DataTable)
   Using  dbAdpBook As New SqlClient.SqlDataAdapter("SELECT * FROM Publisher", dbConn)
            dbAdpBook.Fill(table)
   End Using
End Sub

[riechan]

When you insert a new record to your database, instead of inserting it directly, you can add a new datarow to the datatable and then update that datatable to your database. If you choose to go this route, there's no need to "refresh" the combobox's datasource. However, if you choose to leave it the way it is now, you will need to re-query your database. You don't ned to rebind the datatable to your combobox though. Some thing like this will do:

Private Sub UpdatecmbAuthorDataSource()
   Dim table As DataTable = DirectCast(cmbAuthor.DataSource, DataTable)
   Using  dbAdpBook As New SqlClient.SqlDataAdapter("SELECT * FROM Publisher", dbConn)
            dbAdpBook.Fill(table)
   End Using
End Sub

The code above doesn't seem to refresh the combo box's contents; more like it appends the contents of the new query statement.

[stanav]

Simply clear the table before filling it...

table.Clear()
dbAdpBook.Fill(table)