Mini Kabibi Habibi

Imports Microsoft.VisualBasic
Imports System
Imports System.Collections
Imports System.ServiceModel.DomainServices.Client
Imports System.Windows
Imports DevExpress.Xpf.DemoBase.Web
Imports DevExpress.Xpf.DemoBase.Web.Services

Namespace GridDemo
	Partial Public Class RIAServices
		Inherits GridDemoModule
		Private domainContext As New NWindDomainContext()
		Public Sub New()
			InitializeComponent()

			DataContext = domainContext
			LoadDataSource()
		End Sub
		Private Sub Button_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
			LoadDataSource()
		End Sub

		Private Sub LoadDataSource()
			grid.Columns.Clear()
			grid.ItemsSource = SelectSource(TryCast(listBoxEdit.EditValue, String))
		End Sub
		Private Function SelectSource(ByVal tableName As String) As IEnumerable
			Select Case tableName
				Case "Invoices"
					Return GetSource(Of Invoices)(Function() domainContext.GetInvoicesQuery())
				Case "Customers"
					Return GetSource(Of Customers)(Function() domainContext.GetCustomersQuery())
				Case "Employees"
					Return GetSource(Of Employees)(Function() domainContext.GetEmployeesQuery())
				Case "Products"
					Return GetSource(Of Products)(Function() domainContext.GetProductsQuery())
				Case Else
					Throw New NotImplementedException()
			End Select
		End Function
		Private Function GetSource(Of T As Entity)(ByVal getQuery As Func(Of EntityQuery(Of T))) As IEnumerable
			Dim loadOperation As LoadOperation(Of T) = domainContext.Load(Of T)(getQuery(), New Action(Of LoadOperation(Of T))(AddressOf OnCompleted), Nothing)
			Return loadOperation.Entities
		End Function
		Private Sub OnCompleted(ByVal op As LoadOperation)
			If op.HasError Then
				MessageBox.Show("Connection could not be established." & Environment.NewLine & op.Error.Message, "Connection Error", MessageBoxButton.OK)
				op.MarkErrorAsHandled()
			End If
		End Sub
	End Class
End Namespace