使用分派器解除对Wpf Ui的阻止

Question

I am working on windows app which generates various results of testing. The UI provides a button Results which has various methods as event handlers. These methods are provided by an API module. The module fetches the data from warehouse and then displays it to the user. The API call is asynchronous.

But UI gets blocked once the button is clicked. After quite some readings , I came to know that Dispatcher helps in running a process in background . Dispatcher can be invoked/call only by the UI thread. How can I implement dispatcher to keep the UI away from being blocked?

The function in c# looks something like this

private async void get_results(object sender, RoutedEventArgs e)
{
      List<resultsummary> data = new List<resultsummary>();
      if(id==plan_id)
        {
           data= await getdata.getsummary(id, name);
         }           
} 

Edit:-

This is my understanding of async and await in the above code. But it gives an error cannot await . The getdata class is in differnet namespace and the method getsummary is defined in that space.

The main objective is to unblock the UI and how to go about this using Dispatcher technique?

Answer 1

You don't need to use a Dispatcher to do what you want. In order to fetch data on a background thread and then pass that data from the background thread to the UI thread, you can use the Task class .

Task.Factory.StartNew((Func<YourDataType>)delegate()
{
    // Fetch data on background thread here (return YourDataType, whatever that is)
    return DataAccessClass.GetData();
}).ContinueWith((Task<YourDataType> task) =>
{
    // Update controls with result on UI thread here
    YourUiProperty = task.Result;
}, TaskScheduler.FromCurrentSynchronizationContext());

Obviously, you'll need to replace the YourDataType type with whatever your data type is.

Answer 2

You can use Action ...

Put your code in an Action like this"

Action action = () =>
{
    // your code...
};

assume that you have a label to show result

myLabel.Dispatcher.BeginInvoke(action);