WPF MVVM Progress Dialog Example

This is a quick example WPF application that shows an MVVM-style progress meter dialog, using the .NET 4.5 Task Parallel Library (TPL):

An injectable, stateless IProgressDialogService, that can be injected for unit testing purposes.
A progress meter using .NET 4 Tasks (not BackgroundWorkers).
Cancelling of Tasks via CancellationTokens.
Exception handling back to the original thread.
Reporting background progress updates via IProgress<T>.
Tasks can either be declared as void, or have a return value.
Progress can be reported from multiple tasks chained together.
Using an attached property to hide the close button in the progress dialog's title bar using Win32 interop.
Using an attached property to implement a close window command using MVVM.

Note it uses MVVM light for some INotifyPropertyChanged and DispatcherHelper stuff.

Example Usage

The following example shows how you might set up a simple progress dialog, that can be cancelled and reports progress.

public class MyLongRunningCommand : ICommand
{
    IProgressDialogService dialogService;

    public void Execute(object parameter)
    {
        dialogService.Execute(DoWork, new ProgressDialogOptions { WindowTitle = "Loading files" });
    }

    void DoWork(CancellationToken cancellationToken, IProgress<string> progress)
    {
        for (int i = 0; i < 100; i++)
        {
            cancellationToken.ThrowIfCancellationRequested();

            progress.Report(String.Format("Processing task {0}", i));

            // Do some work
            Thread.Sleep(TimeSpan.FromMilliseconds(100));
        }
    }

    ...
}

Example Usage - Async Task Composition

The following example shows how you might set up a progress dialog that is composed of multiple tasks chained together (that are cancellable and each report progress), and provide a return value.

public class MyLongRunningCommand : ICommand
{
    readonly IProgressDialogService dialogService;

    public void Execute(object parameter)
    {
        Task<int> task = dialogService.ExecuteAsync(DoWork, new ProgressDialogOptions { WindowTitle = "Loading files" });

        MessageBox.Show(String.Format("Result = {0}", task.Result));
    }

    static async Task<int> DoWork(CancellationToken cancellationToken, IProgress<string> progress)
    {
        return await Task.Factory.StartNew(() => progress.Report("First"), cancellationToken)
                         .ContinueWith(_ => Thread.Sleep(1000), cancellationToken)
                         .ContinueWith(_ => progress.Report("Second"), cancellationToken)
                         .ContinueWith(_ => Thread.Sleep(1000), cancellationToken)
                         .ContinueWith(_ => 42);
    }

    ...
}

IProgressDialogService

The following signatures are supported - Execute (no return value) and TryExecute (a return value is expected, but will return false if cancelled).

public interface IProgressDialogService
{
    /// <summary>
    /// Executes a non-cancellable task.
    /// </summary>
    void Execute(Action action, ProgressDialogOptions options);

    /// <summary>
    /// Executes a cancellable task.
    /// </summary>
    void Execute(Action<CancellationToken> action, ProgressDialogOptions options);

    /// <summary>
    /// Executes a non-cancellable task that reports progress.
    /// </summary>
    void Execute(Action<IProgress<string>> action, ProgressDialogOptions options);

    /// <summary>
    /// Executes a cancellable task that reports progress.
    /// </summary>
    void Execute(Action<CancellationToken, IProgress<string>> action,
                 ProgressDialogOptions options);

    /// <summary>
    /// Executes a non-cancellable task, that returns a value.
    /// </summary>
    bool TryExecute<T>(Func<T> action, ProgressDialogOptions options,
                       out T result);

    /// <summary>
    /// Executes a cancellable task that returns a value.
    /// </summary>
    bool TryExecute<T>(Func<CancellationToken, T> action,
                       ProgressDialogOptions options, out T result);

    /// <summary>
    /// Executes a non-cancellable task that reports progress and returns a value.
    /// </summary>
    bool TryExecute<T>(Func<IProgress<string>, T> action,
                       ProgressDialogOptions options, out T result);

    /// <summary>
    /// Executes a cancellable task that reports progress and returns a value.
    /// </summary>
    bool TryExecute<T>(Func<CancellationToken, IProgress<string>, T> action,
                       ProgressDialogOptions options, out T result);

    /// <summary>
    /// Executes a non-cancellable async task.
    /// </summary>
    Task ExecuteAsync(Func<Task> action, ProgressDialogOptions options);

    /// <summary>
    /// Executes a cancellable async task.
    /// </summary>
    Task ExecuteAsync(Func<CancellationToken, Task> action, ProgressDialogOptions options);

    /// <summary>
    /// Executes a non-cancellable async task that reports progress.
    /// </summary>
    Task ExecuteAsync(Func<IProgress<string>, Task> action, ProgressDialogOptions options);

    /// <summary>
    /// Executes a cancellable async task that reports progress.
    /// </summary>
    Task ExecuteAsync(Func<CancellationToken, IProgress<string>, Task> action,
                      ProgressDialogOptions options);

    /// <summary>
    /// Executes a non-cancellable async task that returns a value.
    /// </summary>
    Task<T> ExecuteAsync<T>(Func<Task<T>> action, ProgressDialogOptions options);

    /// <summary>
    /// Executes a cancellable async task that returns a value.
    /// </summary>
    Task<T> ExecuteAsync<T>(Func<CancellationToken, Task<T>> action, ProgressDialogOptions options);

    /// <summary>
    /// Executes a non-cancellable async task that reports progress and returns a value.
    /// </summary>
    Task<T> ExecuteAsync<T>(Func<IProgress<string>, Task<T>> action, ProgressDialogOptions options);

    /// <summary>
    /// Executes a cancellable async task that reports progress and returns a value.
    /// </summary>
    Task<T> ExecuteAsync<T>(Func<CancellationToken, IProgress<string>, Task<T>> action,
                            ProgressDialogOptions options);
}

Credits

This is based upon Jürgen Bäurle's original blog post here: http://www.parago.de/2011/04/how-to-implement-a-modern-progress-dialog-for-wpf-applications/

rdingwall/wpf-mvvm-task-progress-dialog

ErrorLooks like something went wrong!

About

Resources

Uh oh!

Stars

Watchers

Forks

Releases

Packages 0

Uh oh!

Languages

Error
Looks like something went wrong!

Packages