I have a user control that has some public properties (like Dirty :boolean) and an event (ControlValueChanged) that change that property.
I added that control to a form. In the form I have a button (btnOK) and I want to bind the property Enabled of the button to the Dirty property.
I read http://msdn.microsoft.com/en-us/library/ms229614.aspx but I face some problems to implement this to my project.
My code in the form:
btnOK.DataBindings.Add("Enabled", Me.wwdp, "Dirty") 'wwdp is my user Control
So from my research I have to add in my custom control:
Imports System.ComponentModel
Public Class wwDynamicPanel
Implements INotifyPropertyChanged
Public Event PropertyChanged As PropertyChangedEventHandler _
Implements INotifyPropertyChanged.PropertyChanged
Public Property Dirty As Boolean
Get
Return mbDirty
End Get
Set(ByVal value As Boolean)
mbDirty = value
NotifyPropertyChanged()
End Set
End Property
Private Sub NotifyPropertyChanged(<CallerMemberName()> Optional ByVal propertyName As String = Nothing)
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
End Sub
I get an error : Type 'CallerMemberName' is not defined.
The thing is that I haven't found in msdn anything more.
I am very sorry. The link in MSDN was for framework 4.5
I found the right http://msdn.microsoft.com/en-us/library/ms184414(v=vs.100).aspx. for my framework
and I solved the problem.
I am leaving the question because someone else find it useful.
So the working code is:
Imports System.ComponentModel
Public Class wwDynamicPanel
Implements INotifyPropertyChanged
Public Event PropertyChanged As PropertyChangedEventHandler _
Implements INotifyPropertyChanged.PropertyChanged
Public Property Dirty As Boolean
Get
Return mbDirty
End Get
Set(ByVal value As Boolean)
mbDirty = value
NotifyPropertyChanged("Dirty")
End Set
End Property
Private Sub NotifyPropertyChanged(ByVal info As String)
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(info))
End Sub
Related
I have set up Entity Framework with my VB.NET project. I have a model class that takes the data from a table from my MS SQL Server DB. My ListBox object is filled from the model class. What I am trying to do is when a user clicks on an item on from the listbox the text box is populated with the data from the table. If the user clicks on a mustang the text boxes are filled with the model, make, and year of a mustang.
I am using INotifyPropertyChanged in a viewmodel class that I thought would allow me to get each part of the dataset.
This code shows only one part of the requirements to better simplify the post
Public Class CarViewModel
Implements INotifyPropertyChanged
Private _SelectedCarModelName As CarModel
Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
Public Property SelectedCarModelName () As CarModel
Get
Return _SelectedCarModelName
End Get
Set(ByVal value As CarModel)
_SelectedCarModelName = value
OnPropertyChanged("CarName")
End Set
End Property
Public Overridable Sub OnPropertyChanged(propertyName As String)
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
End Sub
End Class
My Textbox Data bind looks like this. My Textbox resides on the frm.vb.
txtCarName.DataBindings.Add("Text", _carViewModel.SelectedCarModelName.CarName, "CarName", True, DataSourceUpdateMode.OnPropertyChanged)
When I click on an item on the list it will access the property, but it will not set the property change. I know I am doing something wrong but I just don't know what it is.
******UPDATED*******
ViewModel
Public Class CarViewModel
Implements INotifyPropertyChanged
Private _SelectedCarModelName As CarModel
Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
Public Property SelectedCarModelName As CarModel
Get
Return _SelectedCarModelName
End Get
Set(ByVal value As CarModel)
_SelectedCarModelName= value
OnPropertyChanged("SelectedCarModelName ")
End Set
End Property
Public Sub OnPropertyChanged(propertyName As String)
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
End Sub
End Class
Windows Form TextBox
**************Edited*******************
private _CarViewModel As CarViewModel
Dim bs As New BindingSource(_CarViewModel , Nothing)
txtCarName.DataBindings.Add _
("Text", bs, "SelectedCarModelName", True, DataSourceUpdateMode.OnPropertyChanged, String.Empty)
After I have restarted everything, for some reason my machine likes that, I am not getting an error anymore. When I debug the code is iterating through the Getter 3x, the number of fields. but it is not getting an output for the textbox.
I created this custom control named Cflowcontrol and I need to know when the FlowDirection of this control changes
So this is what I did:
Inherits FlowLayoutPanel
Implements INotifyPropertyChanged
Private Fdirection As FlowDirection
Public Event FDirectionChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
Private Sub NotifyPropertyChanged(ByVal info As String)
RaiseEvent FDirectionChanged(Me, New PropertyChangedEventArgs(info))
End Sub
Shadows Property FlowDirection As FlowDirection
Get
Return Fdirection
End Get
Set(value As FlowDirection)
If value <> Fdirection Then
Fdirection = value
NotifyPropertyChanged("FlowDirection")
End If
End Set
End Property
So far so good it tells me when the property changes it value
the problem is that the flowdirection of the controls within the panel doesn't change anymore
You need to tell the base control to update itself:
Protected Sub OnNotifyPropertyChanged(info As String)
RaiseEvent FDirectionChanged(Me, New PropertyChangedEventArgs(info))
End Sub
Shadows Property FlowDirection As FlowDirection
Get
Return MyBase.FlowDirection
End Get
Set(value As FlowDirection)
If value <> MyBase.FlowDirection Then
MyBase.FlowDirection = value
OnNotifyPropertyChanged("FlowDirection")
End If
End Set
End Property
I'm trying to update my UI when a property in my BL class changes. Please can someone advise the best way to do this in vb.net
Not a really precise question so I will explain the standard way (in my opinion).
Implement the INotifyPropertyChanged interface in your class and handle the PropertyChanged event of your object.
First the the class of the object that contains the property in question:
Public Class MySweetClass
Implements System.ComponentModel.INotifyPropertyChanged
Private _MyProperty As String
Public Property MyProperty As String
Get
Return _MyProperty
End Get
Set(value As String)
_MyProperty = value
RaiseEvent PropertyChanged(Me, New System.ComponentModel.PropertyChangedEventArgs("MyProperty"))
End Set
End Property
Public Event PropertyChanged(sender As Object, e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged
End Class
Notice that the PropertyChanged event is raised once the value of the property changes.
In your form handle this event:
Public Class Form1
Private WithEvents MySweetObject As MySweetClass
Private Sub MySweetObject_PropertyChanged(sender As Object, e As System.ComponentModel.PropertyChangedEventArgs) Handles MySweetObject.PropertyChanged
'Update gui here
End Sub
End Class
This lets you update the GUI whenever the value changes.
Conceptually, I am a little bit lost on Events themselves, so any information here would be helpful.
Specifically, I have a very simple Property Setter which raises an event, and I want to confirm
that this event is raised and also
that the proper parameters have been passes to said event. (although 2. may be unnecessary for this particular event.)
I am trying to contain the overhead in my Unit Testing project, that is, avoid any additional coding in the project being tested.
The code is as follows.
Public Class myItem
Shared Event ItemOpened As EventHandler(Of EventArgs)
.........
Public Property Open() As Boolean
Get
Return mOpen
End Get
Set(ByVal value As Boolean)
mOpen = value
RaiseEvent ItemOpened(Me, New EventArgs)
End Set
End Property
All code is being done in VB.net, which is primary reason why I have not found a good enough resource online for this yet. And also, I am not using a third-party mocking framework such as Nunit or RhinoMock, only MS built in Unit Testing frameworks in VS2012.
Also, similarly, I would like to test FirePropertyChangedNotification() on certain setter methods such as follows....
Public Property myBool() As Boolean
Set(ByVal Value As Boolean)
FirePropertyChangedNotification("myBool")
mViewOnly = Value
End Set
End Property
In which FirstPropertyChangedNotification() is as follows.....
Protected Sub FirePropertyChangedNotification(ByVal propName As String)
If Not Initializing Then
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propName))
RaiseEvent EntityChanged(Me, New PropertyChangedEventArgs(propName))
End If
End Sub
I'm not sure why you want to use Fakes here... You can just use a delegate in you test to subscribe to your event. Now change the property from the test and set a boolean or even place the assert in the delegate.
This is what I'd do in C#, autoconverted to VB.NET (which in my case is very rusty...) This works on my machine. Any improvements from a VB.NET expert are welcome:
Imports Microsoft.VisualStudio.TestTools.UnitTesting
Imports System.ComponentModel
Namespace UnitTestProject2
Public Class Sut
Implements INotifyPropertyChanged
Public Property StringProperty() As String
Get
Return String.Empty
End Get
Set(value As String)
OnPropertyChanged("StringProperty")
End Set
End Property
Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
Protected Sub OnPropertyChanged(ByVal name As String)
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(name))
End Sub
End Class
<TestClass> _
Public Class UnitTest1
<TestMethod> _
Public Sub TestMethod1()
Dim sut As New Sut()
Dim triggered = False
AddHandler sut.PropertyChanged, Sub(o, e)
Assert.AreEqual("StringProperty", e.PropertyName)
triggered = True
End Sub
sut.StringProperty = "test"
Assert.IsTrue(triggered)
End Sub
<TestMethod> _
Public Sub TestMethod2()
Dim sut As New Sut()
Dim triggered = False
AddHandler sut.PropertyChanged, Sub(o, e)
Assert.AreSame(sut, o)
triggered = True
End Sub
sut.StringProperty = "test"
Assert.IsTrue(triggered)
End Sub
End Class
End Namespace
IN VB.NET (not c#)...
I want to create an event than can be canceled by the listener. Just like you can cancel the closing event of a winforms form in which case the form won't close.
I have already implemented a derived class from EventArgs that has a settable Cancel property as follows:
Public Class AnnounceNavigateEventArgs
Inherits EventArgs
Private _cancel As Boolean = False
''' <summary>
''' Initializes a new instance of the AnnounceNavigateEventArgs class.
''' </summary>
Public Sub New(ByRef cancel As Boolean)
_cancel = cancel
End Sub
Public Property Cancel() As Boolean
Get
Return _cancel
End Get
Set(ByVal value As Boolean)
_cancel = value
End Set
End Property
End Class
Notice that I am passing the cancel argument byRef to the constructor.
The listener I have setup is setting the property to Cancel=True. I thought ByRef meant that both _cancel and cancel would point to the same location on the stack and that setting _cancel=true would therefore make the cancel = true. But this is not the behavior I am getting. _cancel becomes true in the setter but I guess the argument to the constructor remains false.
What is the proper way to do this in vb.net?
Seth
You can re-use the System.ComponentModel.CancelEventArgs class in the .NET framework.
Public Event Announcing As EventHandler(Of AnnounceNavigateEventArgs)
Protected Sub OnAnnounce()
Dim e As New AnnounceNavigateEventArgs
RaiseEvent Announcing(Me, e)
If Not e.Cancel Then
' announce
End If
End Sub
Public Class AnnounceNavigateEventArgs
Inherits System.ComponentModel.CancelEventArgs
End Class