Async await for load files in WPF

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I am trying to do an async operation in UploadBtnExecute method.I am working this on wpf. But it shows some error.

error are :-
error 1::-'Task UploadBtnExecute(object)' has the wrong return type

error 2::- 'bool' does not contain a definition for 'GetAwaiter' and no accessible extension method 'GetAwaiter' accepting a first argument of type 'bool' could be found (are you missing a using directive or an assembly reference?)

What I have tried:

button click event to trigger a function

C#

UploadBtnClick = new RelayCommands(UploadBtnExecute, UploadBtnCanExecuteUpload);

C#

public  async Task UploadBtnExecute(object param)
{
  Progress windowShow = new Progress();
            windowShow.Show();
            await  UploadFiles();
            windowShow.Hide();
}

C#

public bool UploadFiles(List<Item>  selectedFiles)
        {
//do some upload code here

return true;
}

Posted 23-Jan-21 4:51am

john321a

Updated 23-Jan-21 21:58pm

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RickZeeland · Answer 1 · 2021-01-23T09:07:00

Solution 1

See the DownloadFileAsync example here: Async and Await[^]

Posted 23-Jan-21 9:07am

RickZeeland

George Swan · Answer 2 · 2021-01-23T21:58:00

The problem here is that your UploadFiles method is not async and does not return a Task. If you are uploading from a file, you can use one of the asynchronous methods to accomplish that. Something like

C#

public async Task<bool> UploadFiles(List<Item> selectedFiles)
 {
     string filePath = @"c:\temp\Data.txt";
     using var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
     using var streamReader = new StreamReader(fileStream);//uses default encoding UTF8
     string data = await streamReader.ReadToEndAsync();
     //do something
     return data.Contains("spam");
 }