Linq to Sql example

linq to sql
Still a bit fuzzy.


In Databse explorer, add an MDF type file. O/R mapping only works with MDF files, not SDF or MDB files.




pROJECT > aDD cLASS > Linq to Sql
If your database is Foo, it is best to label it as Foo, thereby creating Foo.dbml.
You have created a customer object. It opens up the O/R designer. Take a note of the Name property. It'll be something like $BazDataContext


Drag the relevant table from the Database Explorer to the O/R designer. that creates a table object. It automatically created a LinqToSql class for you.


Press save.

Go to Data Sources tab (on right).
Add new data source
Choose a Data Source Type: Object
Expand your application name until you find the relevant object
This will create a data source in the Data Source window.


Go to a form.

From the data sources panel, drag the dataset you are interested in onto the form.




Enable save:
Click the save button
Enabled: True
double-click it. Enter code for 
PeopleBindingNavigatorSaveItem_Click


You can add a search button and obtain code like this:
Public Class Form2

    Private Db As New BazDataContext()

    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Db.Log = Console.Out
        MySubitems()
        

    End Sub

    Private Sub MySubitems()
        Dim qryString = "*" & txtSearch.Text & "*"

        Dim recs = From rec In Db.Peoples _
                   Where rec.name Like qryString _
                   Order By rec.name _
                   Select rec
        Me.PeopleBindingSource.DataSource = recs
    End Sub
    Private Sub PeopleBindingNavigatorSaveItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PeopleBindingNavigatorSaveItem.Click
        Me.Validate()
        Me.PeopleBindingSource.EndEdit()

        Try
            Db.SubmitChanges()
            MsgBox("Saved changes")
        Catch ex As Exception
            MsgBox(ex.ToString)
        End Try

    End Sub

    Private Sub ToolStripButton1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton1.Click
        MySubitems()
    End Sub

    Private Sub txtSearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtSearch.Click

    End Sub
End Class




Created: 04-Jun-2009