Converting an string to a enum type using TValue?

Question

I want to convert an string to an enum type using TValue, I googled but I didn't find how to do that.

type 
  TEnumTest = (etFirst, etSecond);

var 
  D: TEnumTest;
begin
  D := StrToENumTest('etFirst');
end;

function StrToEnumTest(pStr:String):TEnumTest;
var 
  V: TValue;
begin
  V := TValue.From<String>(pstr);
  Result := V.AsType<TEnumTest>;
end;

It doesn't work. That's must be something stupid I'm not seeing - but I didn't found it. What I made wrong?

I know how to use GetEnumValue.

Answer 1

What you're not seeing is the way TValue was designed. It's intended specifically as a way to contain values, not a way to convert them. If you want to convert between srtings and enums, as you said, you already know how. Use the functions provided for that purpose in TypeInfo.

Answer 2

So you know how to do this:

function StrToEnumTest(aStr:String):TEnumTest;
begin
  result := TEnumTest(GetEnumValue(TypeInfo(TEnumTest),aStr));
end;

But you don't want to do it that way? Why? I wish we could do this:

inline function StrToEnumTest(aStr:String):<T>;
begin
  result := <T>(GetEnumValue(TypeInfo(<T>),aStr));
end;