Perform Time-Consuming Operation while Showing Busy Indicator

Environment

Product Version 2019.3.917
Product RadBusyIndicator for WPF

Description

How to display a busy indicator while executing a heavy operation.

Solution

To perform the heavy operation without blocking the UI thread, you can create a BackgroundWorker and utilize its DoWork and RunWorkerCompleted events.

Example 1: Using the BackgroundWorker in the viewmodel

public class MainViewModel : ViewModelBase 
{ 
    private ObservableCollection<string> items; 
    private BackgroundWorker BackgroundWorker = new BackgroundWorker(); 
    private bool isBusy; 
 
    public MainViewModel() 
    { 
        this.DoWorkCommand = new DelegateCommand(this.OnDoWorkExecuted); 
 
        this.BackgroundWorker.DoWork += BackgroundWorker_DoWork; 
        this.BackgroundWorker.RunWorkerCompleted += BackgroundWorker_RunWorkerCompleted; 
        this.BackgroundWorker.RunWorkerAsync(); 
    } 
 
    public ICommand DoWorkCommand { get; private set; } 
 
    public bool IsBusy 
    { 
        get 
        { 
            return this.isBusy; 
        } 
 
        set 
        { 
            if (this.isBusy != value) 
            { 
                this.isBusy = value; 
                this.OnPropertyChanged(() => this.IsBusy); 
            } 
        } 
    } 
 
    public ObservableCollection<string> Items 
    { 
        get 
        { 
            return this.items; 
        } 
 
        set 
        { 
            if (this.items != value) 
            { 
                this.items = value; 
                this.OnPropertyChanged(() => this.Items); 
            } 
        } 
    } 
 
    private ObservableCollection<string> GetData() 
    { 
        return new ObservableCollection<string>() 
        { 
            "Item 1", 
            "Item 2", 
            "Item 3", 
            "Item 4", 
            "Item 5" 
        }; 
    } 
 
    private void OnDoWorkExecuted(object parameter) 
    { 
        this.BackgroundWorker.RunWorkerAsync(); 
    } 
 
    private void BackgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) 
    { 
        this.IsBusy = false; 
    } 
 
    private void BackgroundWorker_DoWork(object sender, DoWorkEventArgs e) 
    { 
        this.IsBusy = true; 
        Thread.Sleep(3000); 
        this.Items = GetData(); 
    } 
} 
In the BackgroundWorker_DoWork method we put the thread to sleep for 3 seconds in order to simulate the time-consuming operation but in a real scenario you can make a database call or some heavy computation here.

You can then bind your view to this viewmodel as demonstrated in Example 2.

Example 2: Defining and binding the RadBusyIndicator

<Grid> 
    <Grid.DataContext> 
        <local:MainViewModel /> 
    </Grid.DataContext> 
    <Grid.RowDefinitions> 
        <RowDefinition Height="*"/> 
        <RowDefinition Height="Auto"/> 
    </Grid.RowDefinitions> 
 
    <telerik:RadBusyIndicator IsBusy="{Binding IsBusy}"> 
        <telerik:RadListBox ItemsSource="{Binding Items}" /> 
    </telerik:RadBusyIndicator> 
 
    <Button Content="Do Work" Command="{Binding DoWorkCommand}" Grid.Row="1" /> 
</Grid> 

See Also

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