Is it legal and possible to access the return value in a finally block?

问题

I wish to set a usererror string before leaving a function, depending on the return code and variable in the function.

I currently have:

Dim RetVal as RetType

try
...
if ... then
    RetVal = RetType.FailedParse
    end try
endif
...

finally
    select case RetVal
        case ...
            UserStr = ...
    end select
end try

return RetVal

Is it possible to use return RetType.FailedParse, then access this in the finally block?

回答1:

The only real way of doing this in C# would be to declare a variable at the start of the method to hold the value - i.e.

SomeType result = default(SomeType); // for "definite assignment"
try {
   // ...
   return result;
}
finally {
    // inspect "result"
}

In VB, you might be able to access the result directly - since IIRC it kinda works like the above (with the method name as "result") anyway. Caveat: I'm really not a VB person...

回答2:

Declare the variable out of the try block, and check in the finally block if it has been set.

回答3:

I was wondering whether in VB one could (legally) do:

Public Function MyFunc() as integer
    Try
      if DoSomething() = FAIL Then
        return FAIL
      end if

  Finally
      if MyFunc = FAIL then
          Me.ErrorMsg = "failed"
      endif
  End Try
End Function

I know setting MyFunc = FAIL is legal (as a hang-over from VB), is it write-only or readable? My concern it that this is poor coding as