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POWPF AttachedCommandsBehavior in VB.NET
 

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    <p>Can anybody give me an example how to implement AttachedCommands?</p> <p>There are some examples in C# and I think it is very similar to C# but I have problems to translate the code to VB.NET.</p> <p>At the moment my try to translate a C# AttachedCommand-Class to VB.net looks like that:</p> <pre><code>Imports System Imports System.Collections.Generic Imports System.Linq Imports System.Text Imports System.Windows Imports System.Windows.Input Imports System.Reflection Public Class AttachedCommand Inherits DependencyObject #Region "CommandParameter-Class" Private NotInheritable Class CommandParameter Public Shared ReadOnly Property DefaultCP() As CommandParameter Get Return New CommandParameter() End Get End Property Private _command As ICommand Public Property Command() As ICommand Get Return _command End Get Set(ByVal value As ICommand) _command = value End Set End Property Private _eventName As String Public Property EventName() As String Get Return _eventName End Get Set(ByVal value As String) _eventName = value End Set End Property Private _callBack As [Delegate] Public Property Callback() As [Delegate] Get Return _callBack End Get Set(ByVal value As [Delegate]) _callBack = value End Set End Property End Class #End Region #Region "Properties" Private Shared _parameter As IDictionary(Of DependencyObject, CommandParameter) Private Shared Property Parameter() As IDictionary(Of DependencyObject, CommandParameter) Get Return _parameter End Get Set(ByVal value As IDictionary(Of DependencyObject, CommandParameter)) _parameter = value End Set End Property Public Property Command() As ICommand Get Return GetValue(CommandProperty) End Get Set(ByVal value As ICommand) SetValue(CommandProperty, value) End Set End Property Public Shared ReadOnly CommandProperty As DependencyProperty = _ DependencyProperty.Register("Command", _ GetType(ICommand), GetType(AttachedCommand), _ New UIPropertyMetadata(AddressOf CommandChanged)) Public Property EventName() As String Get Return GetValue(EventNameProperty) End Get Set(ByVal value As String) SetValue(EventNameProperty, value) End Set End Property Public Shared ReadOnly EventNameProperty As DependencyProperty = _ DependencyProperty.Register("EventName", _ GetType(String), GetType(AttachedCommand), _ New UIPropertyMetadata(AddressOf EventNameChanged)) #End Region #Region "Event-Handler" Public Shared Sub CommandChanged(ByVal dependencyObject As DependencyObject, ByVal args As DependencyPropertyChangedEventArgs) If Not Parameter.ContainsKey(dependencyObject) Then Parameter.Add(dependencyObject, CommandParameter.DefaultCP) End If If (Not Parameter(dependencyObject).Callback = Nothing) AndAlso (Not args.OldValue = Nothing) Then _RemoveEventHandler(dependencyObject) End If Parameter(dependencyObject).Command = CType(args.NewValue, ICommand) _AttachEventHandler(dependencyObject) End Sub Public Shared Sub EventNameChanged(ByVal dependencyObject As DependencyObject, ByVal args As DependencyPropertyChangedEventArgs) If Not Parameter.ContainsKey(dependencyObject) Then Parameter.Add(dependencyObject, CommandParameter.DefaultCP) End If End Sub #End Region #Region "Helper" Private Shared Sub _RemoveEventHandler(ByVal dependencyObject As DependencyObject) If dependencyObject Is Nothing Then Throw New ArgumentNullException("DependencyObject is null.") End If If Not Parameter.ContainsKey(dependencyObject) Then Exit Sub End If Dim param As CommandParameter = Parameter(dependencyObject) If param.Callback Is Nothing Then Throw New InvalidProgramException("Cannot remove Callback. Callback is null.") End If Dim eventInfo As EventInfo = dependencyObject.GetType().GetEvent(param.EventName) If eventInfo Is Nothing Then Throw New InvalidProgramException(String.Format("Cannot find an event with the name &lt;{0}&gt;", param.EventName)) End If eventInfo.RemoveEventHandler(dependencyObject, param.Callback) End Sub Private Shared Sub _AttachEventHandler(ByVal dependencyObject) If dependencyObject Is Nothing Then Throw New ArgumentNullException("DependencyObject is null") End If If Not Parameter.ContainsKey(dependencyObject) Then Exit Sub End If Dim param As CommandParameter = Parameter(dependencyObject) If param.Command Is Nothing Or String.IsNullOrEmpty(param.EventName) Then Exit Sub End If Dim eventInfo As EventInfo = dependencyObject.GetType.GetEvent(param.EventName) If eventInfo Is Nothing Then Throw New InvalidProgramException(String.Format("Cannot find an event with the name &lt;{0}&gt;", param.EventName)) End If eventInfo.AddEventHandler(dependencyObject, param.Callback) End Sub Private Shared Sub _CommandExecutAction(ByVal parameter As CommandParameter) parameter.Command.Execute(Nothing) End Sub Private Shared Function _CreateHandler(ByVal eventInfo As EventInfo, ByVal method As Action) As [Delegate] If eventInfo Is Nothing Then Throw New ArgumentNullException("EventInfo is null") End If If method Is Nothing Then Throw New ArgumentNullException("Action-method is null") End If Dim handlerType = eventInfo.EventHandlerType Dim eventParams = handlerType.GetMethod("Invoke").GetParameters() Dim parameters = eventParams.[Select](Function(p) System.Linq.Expressions.Expression.Parameter(p.ParameterType, "x")) Dim body = System.Linq.Expressions.Expression.[Call](System.Linq.Expressions.Expression.Constant(method), method.[GetType]().GetMethod("Invoke")) Dim lambda = System.Linq.Expressions.Expression.Lambda(body, parameters.ToArray()) Return [Delegate].CreateDelegate(handlerType, lambda.Compile(), "Invoke", False) End Function #End Region #Region "INIT" Public Sub New() Parameter = New Dictionary(Of DependencyObject, CommandParameter)() End Sub #End Region End Class </code></pre> <p>But now I have the problem, that the GetValue() and SetValue()-methods are not available. Any ideas?</p> <p><em>Thank you for your help..</em></p>
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