请教关于字符串比较的问题
诚心请教各位大侠，有段程序，需要对返回的类名做判断，但一直不通过，请问该怎么修改？非常感谢！

 function EnumChildWndProc(AhWnd:LongInt;
AlParam:lParam):boolean;stdcall;
    var
WndClassName:string;
WndCaption:string;
ClasName:string;
begin
SetLength(WndClassName,256);
GetClassName(AhWnd,PChar(WndClassName), Length(WndClassName));
WndClassName := StrPas(PChar(WndClassName));

SetLength(WndCaption, 256);
GetWindowText(AhWnd, PChar(WndCaption), Length(WndCaption));
WndCaption := StrPas(PChar(WndCaption));

SetLength(ClasName,256);
ClasName:='combobox';
If CompareStr(ClasName,WndClassName)=0 then //这里是要使用compareStr函数对得到类名做判断，该怎么修改呢？                                        
Begin
.....
end;
result:=true;
end;
end;

[解决办法]
function EnumChildWndProc(AhWnd: LongInt; AlParam: lParam): Boolean; stdcall;
var
WndCaption, WndClassName: array[0..254] of Char;
ClasName: string;
begin
Result := True;
GetClassName(AWnd, @WndClassName, 254);
GetWindowText(AWnd, @WndCaption, 254);
ClasName := ;
if WndClassName = 'combobox' then
begin
.....
end;
end;