Author: Lou Adler

How to use RTTI to determine if a property is a TDateTime 

Answer:

When it comes to RTTI, TDateTime and Double are not the same. That's what the extra 
"type" keyword in TDateTime's declaration is for: to give it its own RTTI, distinct 
from that of Double. Here is an example:

1   program Test;
2   
3   uses
4     TypInfo;
5   
6   {$APPTYPE CONSOLE}
7   {$M+}
8   type
9     TTest = class
10    private
11      FDateTime: TDateTime;
12    published
13      property D: TDateTime read FDateTime write FDateTime;
14    end;
15  
16  var
17    T: TTest;
18    DateInfo: Pointer;
19    TestInfo: PPropInfo;
20  begin
21    T := TTest.Create;
22    DateInfo := TypeInfo(TDateTime);
23    TestInfo := GetPropInfo(T, 'D');
24    writeln(DateInfo = TestInfo^.PropType^);
25    readln;
26  end.


It should print TRUE on the console.