Cannot implicitly convert type string to System Threading Tasks Task string

Question

I am new to asynchronous programming  so after going through some async sample codes  I thought of writing a simple async code  I created a simple Winform application and inside the Form I wrote the following code  But its just not working  private Task lt string gt  methodAsync         Thread Sleep 10000       return  Hello     Error  Cannot implicitly convert type  string  to  System Threading Tasks Task lt string gt      private async void button1 Click object sender  EventArgs e        string s   await methodAsync        MessageBox Show s       Could someone please put some light here

User · Answer

source         public async Task lt string gt  methodName                              return Data                        Consumption      methodName   Result    Hope this helps

User · Answer

The listed return type of the method is Task lt string gt    You re trying to return a string   They are not the same  nor is there an implicit conversion from string to Task lt string gt   hence the error   You re likely confusing this with an async method in which the return value is automatically wrapped in a Task by the compiler   Currently that method is not an async method   You almost certainly meant to do this   private async Task lt string gt  methodAsync          await Task Delay 10000       return  Hello       There are two key changes   First  the method is marked as async  which means the return type is wrapped in a Task  making the method compile   Next  we don t want to do a blocking wait   As a general rule  when using the await model always avoid blocking waits when you can   Task Delay is a task that will be completed after the specified number of milliseconds   By await-ing that task we are effectively performing a non-blocking wait for that time  in actuality the remainder of the method is a continuation of that task    If you prefer a 4 0 way of doing it  without using await   you can do this   private Task lt string gt  methodAsync          return Task Delay 10000           ContinueWith t   gt   Hello        The first version will compile down to something that is more or less like this  but it will have some extra boilerplate code in their for supporting error handling and other functionality of await we aren t leveraging here   If your Thread Sleep 10000  is really meant to just be a placeholder for some long running method  as opposed to just a way of waiting for a while  then you ll need to ensure that the work is done in another thread  instead of the current context   The easiest way of doing that is through Task Run   private Task lt string gt  methodAsync          return Task Run     gt                        SomeLongRunningMethod                return  Hello                   Or more likely   private Task lt string gt  methodAsync          return Task Run     gt                        return SomeLongRunningMethodThatReturnsAString

User · Answer

Beyond the problematic use of async as pointed out by  Servy  the other issue is that you need to explicitly get T from Task lt T gt  by calling Task Result  Note that the Result property will block async code  and should be used carefully    Try   private async void button1 Click object sender  EventArgs e        var s   await methodAsync        MessageBox Show s Result

User · Answer

Use FromResult Method  public async Task lt string gt  GetString        System Threading Thread Sleep 5000      return await Task FromResult  Hello

[c#] Cannot implicitly convert type 'string' to 'System.Threading.Tasks.Task<string>'

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