Author: Tomas Rutkauskas

I am building a routine that checks our forms for validity before deploying them. I 
would like to use some kind of structure that tests if a component type has access 
to a certain property, something like: " if (self.Controls[b] has Tag) then ...". 
Can anyone offer suggestions?

Answer:

Here's an example of setting a string property for a component if it exists and 
another for an integer property:

1   procedure SetStringPropertyIfExists(AComp: TComponent; APropName: string;
2     AValue: string);
3   var
4     PropInfo: PPropInfo;
5     TK: TTypeKind;
6   begin
7     PropInfo := GetPropInfo(AComp.ClassInfo, APropName);
8     if PropInfo <> nil then
9     begin
10      TK := PropInfo^.PropType^.Kind;
11      if (TK = tkString) or (TK = tkLString) or (TK = tkWString) then
12        SetStrProp(AComp, PropInfo, AValue);
13    end;
14  end;
15  
16  procedure SetIntegerPropertyIfExists(AComp: TComponent; APropName: string;
17    AValue: Integer);
18  var
19    PropInfo: PPropInfo;
20  begin
21    PropInfo := GetPropInfo(AComp.ClassInfo, APropName);
22    if PropInfo <> nil then
23    begin
24      if PropInfo^.PropType^.Kind = tkInteger then
25        SetOrdProp(AComp, PropInfo, AValue);
26    end;
27  end;