Fire callback after async Task method in C#

Fire callback after async Task method in C#

In C#, you can use the await keyword to wait for an asynchronous task to complete and then execute a callback method. Here's an example:

public async Task MyAsyncMethod(Action callback) { // Perform some async operation await Task.Delay(1000); // Call the callback method callback(); }

In this example, the MyAsyncMethod method performs an asynchronous operation using the Task.Delay method. Once the operation is complete, the callback method is called.

To use this method, you can pass in a lambda expression as the callback parameter, like this:

await MyAsyncMethod(() => { // Callback logic here });

In this example, the lambda expression defines the callback logic to be executed after the MyAsyncMethod completes.

Note that if the callback method needs to access any UI elements or perform any other operations that must be executed on the UI thread, you'll need to use the Dispatcher.Invoke method to marshal the callback method to the UI thread. For example:

public async Task MyAsyncMethod(Action callback) { // Perform some async operation await Task.Delay(1000); // Call the callback method on the UI thread Application.Current.Dispatcher.Invoke(callback); }

In this example, the Dispatcher.Invoke method is used to execute the callback method on the UI thread. This is necessary if the callback method interacts with any UI elements.

Examples

  1. "C# async Task callback pattern"

    • Code:
      public async Task MyAsyncMethod(Action callback) { // Your asynchronous logic here await Task.Delay(1000); callback.Invoke(); }
    • Description: Implements a callback pattern after the completion of an asynchronous method using Action.

  2. "C# async Task callback with TaskCompletionSource"

    • Code:
      public async Task MyAsyncMethodWithCallback() { var tcs = new TaskCompletionSource<bool>(); // Your asynchronous logic here await Task.Delay(1000); // Set the task completion source tcs.SetResult(true); // Callback after async completion tcs.Task.ContinueWith(task => YourCallbackMethod()); }
    • Description: Utilizes TaskCompletionSource to signal task completion and fires a callback after the asynchronous method finishes.

  3. "C# async Task callback with delegate"

    • Code:
      public async Task MyAsyncMethodWithDelegate(Action callback) { // Your asynchronous logic here await Task.Delay(1000); callback.Invoke(); }
    • Description: Introduces a delegate as a callback to be executed after the completion of the asynchronous method.

  4. "C# async Task callback with custom event"

    • Code:
      public event EventHandler MyCallbackEvent; public async Task MyAsyncMethodWithEvent() { // Your asynchronous logic here await Task.Delay(1000); // Fire the event MyCallbackEvent?.Invoke(this, EventArgs.Empty); }
    • Description: Fires a custom event after the asynchronous method completes, allowing subscribers to handle the callback.

  5. "C# async Task callback with continuation"

    • Code:
      public async Task MyAsyncMethodWithContinuation() { // Your asynchronous logic here await Task.Delay(1000); // Callback using continuation await Task.Run(() => YourCallbackMethod()); }
    • Description: Uses the Task.Run method to execute a callback as a continuation after the asynchronous method completes.

  6. "C# async Task callback with Task.Run"

    • Code:
      public async Task MyAsyncMethodWithTaskRun() { // Your asynchronous logic here await Task.Delay(1000); // Callback using Task.Run await Task.Run(() => YourCallbackMethod()); }
    • Description: Applies Task.Run to schedule a callback after the asynchronous method finishes, ensuring it runs on a different thread.

  7. "C# async Task callback with async/await continuation"

    • Code:
      public async Task MyAsyncMethodWithAsyncContinuation() { // Your asynchronous logic here await Task.Delay(1000); // Callback using async/await continuation await YourCallbackMethodAsync(); }
    • Description: Invokes an asynchronous callback using the async/await pattern as a continuation after the async Task method.

  8. "C# async Task callback with Task.Run and lambda"

    • Code:
      public async Task MyAsyncMethodWithLambdaCallback() { // Your asynchronous logic here await Task.Delay(1000); // Callback using Task.Run and lambda await Task.Run(() => { /* Your callback logic here */ }); }
    • Description: Implements a callback using Task.Run and a lambda expression for concise code.

  9. "C# async Task callback with TaskCompletionSource and async/await"

    • Code:
      public async Task MyAsyncMethodWithTCSAndAsyncAwait() { var tcs = new TaskCompletionSource<bool>(); // Your asynchronous logic here await Task.Delay(1000); // Set the task completion source tcs.SetResult(true); // Callback using TaskCompletionSource and async/await await tcs.Task.ContinueWith(async _ => await YourCallbackMethodAsync()); }
    • Description: Combines TaskCompletionSource and async/await for a callback with asynchronous behavior.

  10. "C# async Task callback with Task.FromResult"

    • Code:
      public async Task MyAsyncMethodWithResultCallback() { // Your asynchronous logic here await Task.Delay(1000); // Callback using Task.FromResult await Task.FromResult(YourCallbackMethod()); }
    • Description: Uses Task.FromResult to create a completed Task and invoke a callback after the asynchronous method finishes.

More Tags

alpha-transparency react-async scjp utm notifydatasetchanged supervised-learning iterable reverse xvfb ruby-on-rails-5

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