Question

I’m new to LINQ and am trying to bind a Linq to SQL table to several controls (treeview, textbox, etc). I want to be able to make changes to textbox fields and save those updates back to the database easily.

I’m able to get the data from the database using:

    Private LinqDB As New DataContext(My.Settings.dbConnection)
    Property tblManufacturers As Table(Of dbManufacturers) _
        = LinqDB.GetTable(Of dbManufacturers)()

And binding the stuff to the controls was pretty simple. The TreeView fills with all the ManufacturerNames, and when I click on one it fills the TextBoxes for editing.
The problem is that the results aren’t in the order I want in the treeview.
I was hoping something like:

    Property tblManufacturers As Table(Of dbManufacturers) _
        = LinqDB.GetTable(Of dbManufacturers)().OrderBy("ManufacturerName") 

would work, but alas no.

I know I can use something like

Dim ManufacturerQuery = From ManufacturerName In tblManufacturers Order By ManufacturerName 

But pushing changes back to the database seems more difficult.

EDIT: So, apparently I need to stop being cowardly and just try stuff…

Namespace Controls
    Public Class ManufacturerWarranty

        Private LinqDB As New DataContext(My.Settings.dbConnection)
        Property tblManufacturers As Table(Of dbManufacturers) = LinqDB.GetTable(Of dbManufacturers)()
        Property ManufacturerQuery = From m In tblManufacturers Order By m.ManufacturerName

        Public Sub New()
            InitializeComponent()
        End Sub

        Private Sub ManufacturerWarranty_Loaded(sender As Object, e As System.Windows.RoutedEventArgs) Handles Me.Loaded
            Me.DataContext = Me
        End Sub

        Private Sub TreeView1_MouseDoubleClick(sender As System.Object, e As System.Windows.Input.MouseButtonEventArgs) Handles TreeView1.MouseDoubleClick
            StackPanel1.DataContext = e.OriginalSource.DataContext
        End Sub


        Private Sub cmdSave_Click(sender As Object, e As System.Windows.RoutedEventArgs) Handles cmdSave.Click
            LinqDB.SubmitChanges()
        End Sub
    End Class
End Namespace

And then I just bind my TreeView to ManufacturerQuery instead of tblManufacturers. My Save button still works for submitting changes, even when they are made to ManufacturerQuery instead of tblManufacturers.

Answer 1

Ok, perhaps you want

Dim tblManufacturers As Table(Of dbManufacturers) _
    = LinqDB.GetTable(Of dbManufacturers)() _
        .OrderBy(Function(m) m.ManufacturerName)  

---

So, to commit you’d do

Using linqDB As New DataContext(My.Settings.dbConnection)
    Dim tblManufacturers As Table(Of dbManufacturers) _
        = linqDB.GetTable(Of dbManufacturers)()

    -- change tblManufacturers.

    linqDB.SaveChanges()
End Using

What I wouldn’t do is keep the context open while the user is interacting with the GUI. Likewise I (probably) wouldn’t order the data unless I was displaying it to the user.