Essential C# Async Await  Suggest an edit

TryCatchFinally

As of C# 6.0, the await keyword can now be used within a catch and finally block.

try {
   var client = new AsyncClient();
   await client.DoSomething();
} catch (MyException ex) {
   await client.LogExceptionAsync();
   throw;
} finally {
   await client.CloseAsync();
}

Prior to C# 6.0, you would need to do something along the lines of the following. Note that 6.0 also cleaned up the null checks with the Null Propagating operator.

AsynClient client;
MyException caughtException;
try {
     client = new AsyncClient();
     await client.DoSomething();
} catch (MyException ex) {
     caughtException = ex;
}

if (client != null) {
    if (caughtException != null) {
       await client.LogExceptionAsync();
    }
    await client.CloseAsync();
    if (caughtException != null) throw caughtException;
}

Please note that if you await a task not created by async (e.g. a task created by Task.Run), some debuggers may break on exceptions thrown by the task even when it is seemingly handled by the surrounding try/catch. This happens because the debugger considers it to be unhandled with respect to user code. In Visual Studio, there is an option called “Just My Code”, which can be disabled to prevent the debugger from breaking in such situations.


Table Of Contents
22 Enum
25 GUID
107 Stream
108 Timers
112 Async Await
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