' Developer Express Code Central Example:
' How to populate a List View with data from a LINQ query
' 
' See the http://www.devexpress.com/scid=K18107 KB Article for more information.
' 
' You can find sample updates and versions for different programming languages here:
' http://www.devexpress.com/example=E859

' Developer Express Code Central Example:
' How to populate the list view with data from a LINQ query
' 
' See the http://www.devexpress.com/scid=K18107 KB Article for more information.
' 
' You can find sample updates and versions for different programming languages here:
' http://www.devexpress.com/example=E859


Imports Microsoft.VisualBasic
Imports System
Imports System.Linq
Imports DevExpress.Xpo
Imports System.Reflection
Imports DevExpress.ExpressApp
Imports System.Collections.Generic
Imports SISBusiness.Module.Dennis.Linq


Public NotInheritable Class LinqCollectionSourceHelper
    Private Sub New()
    End Sub
    Public Shared Sub CreateCustomCollectionSource(ByVal sender As Object, ByVal e As CreateCustomCollectionSourceEventArgs)
        Dim listViewInfo As IModelListViewLinq = TryCast((CType(sender, XafApplication)).FindModelView(e.ListViewID), IModelListViewLinq)
        If listViewInfo Is Nothing Then
            Return
        End If
        If String.IsNullOrEmpty(listViewInfo.XPQueryMethod) Then
            Return
        End If
        Dim query As IQueryable = LinqCollectionSourceHelper.InvokeMethod(e.ObjectType, listViewInfo.XPQueryMethod, (CType(e.ObjectSpace, Xpo.XPObjectSpace)).Session)
        If query Is Nothing Then
            Return
        End If
        e.CollectionSource = New LinqCollectionSource(e.ObjectSpace, e.ObjectType, query)
    End Sub
    Public Shared Function GetXPQueryMethods(ByVal type As Type) As String()
        Dim names As New List(Of String)()
        Dim methods() As MethodInfo = type.GetMethods(System.Reflection.BindingFlags.Public Or System.Reflection.BindingFlags.Static)
        For Each mi As MethodInfo In methods
            If IsCompatibleMethod(mi) Then
                names.Add(mi.Name)
            End If
        Next mi
        Return names.ToArray()
    End Function
    Public Shared Function IsCompatibleMethod(ByVal mi As MethodInfo) As Boolean
        Dim pis() As ParameterInfo = mi.GetParameters()
        Return mi.ReturnType IsNot Nothing AndAlso GetType(IQueryable).IsAssignableFrom(mi.ReturnType) AndAlso pis.Length = 1 AndAlso pis(0).ParameterType.IsAssignableFrom(GetType(Session))
    End Function
    Public Shared Function InvokeMethod(ByVal type As Type, ByVal name As String, ByVal session As Session) As IQueryable
        Dim method As MethodInfo = FindMethod(type, name)
        If method Is Nothing Then
            Return Nothing
        End If
        Return CType(method.Invoke(Nothing, New Object() {session}), IQueryable)
    End Function
    Private Shared Function FindMethod(ByVal type As Type, ByVal name As String) As MethodInfo
        Dim methods() As MethodInfo = type.GetMethods(System.Reflection.BindingFlags.Public Or System.Reflection.BindingFlags.Static)
        For Each mi As MethodInfo In methods
            If mi.Name = name AndAlso IsCompatibleMethod(mi) Then
                Return mi
            End If
        Next mi
        Return Nothing
    End Function
    Public Shared Function GetDisplayableProperties(ByVal type As Type, ByVal name As String) As String()
        Dim method As MethodInfo = FindMethod(type, name)
        If method Is Nothing Then
            Return Nothing
        End If
        For Each attribute As CustomQueryPropertiesAttribute In method.GetCustomAttributes(GetType(CustomQueryPropertiesAttribute), False)
            If attribute.Name = "DisplayableProperties" Then
                Return attribute.Value.Split(";"c)
            End If
        Next attribute
        Return Nothing
    End Function
End Class
<AttributeUsage(AttributeTargets.Method)> _
Public NotInheritable Class CustomQueryPropertiesAttribute
    Inherits Attribute
    Private theName As String
    Private theValue As String
    Public ReadOnly Property Name() As String
        Get
            Return theName
        End Get
    End Property
    Public ReadOnly Property Value() As String
        Get
            Return theValue
        End Get
    End Property
    Public Sub New(ByVal theName As String, ByVal theValue As String)
        Me.theName = theName
        Me.theValue = theValue
    End Sub
End Class