RadBusyIndicator Not Showing in MVVM App

[Paul Patterson]

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

[Paul Patterson]

Solved it!

Built an async specific delegate command for my ViewModel and then hooked into that to update the IsBusy binding. Even threw in some view navigation with a RadTransitionControl cherry on top! All is good :)

If you are curious how this was all put together, let me know and I'll post about it on my blog. (Ah, I'll post about it anyway otherwise I'll forget what I did :P )

Cheers!

[Andreas Lindahl]

Hi Paul,

I am very interested in your solution so please do post it on your blog if possible.

Thanks in advance!

[Paul Patterson]

Hi Andreas,

I am working on it right now (www.PaulSPatterson.com). 

Cheers!

[Ronak]

Hi Paul
I am working on MVVM pattern with Command in Silverlight can you please share with me how did u utilize busyIndicator in MVVM.
i will appriciate your work.

[Paul Patterson]

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>
        <!-- Some content here.... -->
        <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

 

[Ronak]

Thanks Paul for your Quick reply.

[Paul Patterson]

Hello,

As promisied, here is the link to the blog posting on how I implemented an asynchronous command delegate to achieve the RadBusyIndicator in an MVVM application. 

   www.PaulSPatterson.com

Cheers!

[Teodor]

Hello Paul,

Please refer also to this online demo to see RadBusyIndicator in a MVVM scenario with proper behavior when changing the IsBusy property. 

Hope this will be of use. We will be glad to assist you further.

Regards,
Teodor
the Telerik team

[Paul Patterson]

I was able to resolve this already (as per the link I provided earlier). Thanks anyway.

[Andreas Lindahl]

http://demos.telerik.com/wpf/?BusyIndicator/Configurator

Unfortunately, this link is broken.

[Vlad]

Hi,

 I've just tried the demo an it works as expected. You can check the attached screenshot. 

Regards,
Vlad
the Telerik team

[Mark]

I would be interested. I glanced at your website and didn't see it.

-Markus

[Konstantina]

Hello Markus,

You can also get the link for the demos from the WPF products' page: http://www.telerik.com/products/wpf.aspx

Kind regards,
Konstantina
the Telerik team

[Rob]

fyi - this is a few years later, following the link to Paul's site triggers my Alvira anti-virus

"The site ahead contains malware"