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RadBusyIndicator Not Showing in MVVM App

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BusyIndicator

This is a migrated thread and some comments may be shown as answers.

Paul Patterson asked on 28 Jan 2011, 07:14 PM

Trying to display a RadBusyIndicator in an WPF MVVM application however the control does not appear when IsBusy binding occurs.

Here is a portion of what is in the user control xaml...

<Grid>

<telerik:RadBusyIndicator IsBusy="{Binding IsBusy}" Grid.Row="0" >

<Grid>

<StackPanel Margin="10,10,10,10">

...some content here...

</StackPanel>

</Grid>

</telerik:RadBusyIndicator>

</Grid>

I bind the IsBusy to a property in my ViewModel, set the property to true, and then fire OnPropertyChanged to rebind the view. Unfortunately the BusyIndicator does not show.

Has anyone experienced this challenge before, and if so, what was done to resolve it?

I'll follow up this post with an example solution that recreates the problem. Until then, let me know if you have any insights into this.

Cheers,

Paul

14 Answers, 1 is accepted

answered on 03 Feb 2011, 10:07 PM

I'll be posting a full example on my blog (soon). Until then, check out this article by Anoot Madhusudanan here. http://amazedsaint.blogspot.com/2010/10/asynchronous-delegate-command-for-your.html .

What I did was, when the async command is executed, the delegate action updates a boolean property (which happens to be named isBusy) in the ViewModel to true. When the async command is done, the isBusy property is set back to false.

For example, in my ViewModel...

Namespace ViewModels

Public Class UserLoginViewModel

Inherits ViewModelBase

Private _isBusy As Boolean = False

Public Property IsBusy As Boolean

Get

Return _isBusy

End Get

Set(ByVal value As Boolean)

_isBusy = value

OnPropertyChanged("IsBusy")

End Set

End Property

Public Property LoginAsyncCommand As ICommand

Public Sub New(ByVal regionManager As IRegionManager, ByVal container As IUnityContainer)

Dim loginAction As Action = New Action(AddressOf LoginExecute)

LoginAsyncCommand = New AsyncDelegateCommand(loginAction, Nothing, Sub() LoadView())

End Sub

Private Sub LoginExecute()

If IsBusy Then

Exit Sub

End If

IsBusy = True

' Do some login stuff here...

IsBusy = False

End Sub

Public Sub LoadView()

Try

If _loginSuccess Then

' Do some view management here.

End If

Catch ex As Exception

LoginSuccess = ex.Message

End Try

End Sub

End Class

End Namespace

AsyncDelegateCommand is a class that is the same that Anoot wrote about.

In the View...

<Grid>

<telerik:RadBusyIndicator IsBusy="{Binding IsBusy}" Grid.Row="0">

<Grid>

<StackPanel>

<Button x:Name="LoginCommand" Content="Login..." Command="{Binding LoginAsyncCommand}"/>

</StackPanel>

</Grid>

</telerik:RadBusyIndicator>

</Grid>

I have a lot more happening in there of course - with Prism and all, but this should get you started.

- Cheers