解决方法
请注意,以下代码仅适用于已发布的类的属性！此外,传递给下面的函数的类的实例至少必须已经定义了发布的部分！
以下是使用旧样式RTTI将已发布的字符串属性值设置为空字符串,将布尔值设置为False.
如果您的Delphi比Delphi 2009更旧,您可能会丢失tkUString类型.如果是这样,请从以下代码中删除：
uses
TypInfo;
procedure ResetPropertyValues(const AObject: TObject);
var
PropIndex: Integer;
PropCount: Integer;
PropList: PPropList;
PropInfo: PPropInfo;
const
TypeKinds: TTypeKinds = [tkEnumeration,tkString,tkLString,tkWString,tkUString];
begin
PropCount := GetPropList(AObject.ClassInfo,TypeKinds,nil);
GetMem(PropList,PropCount * SizeOf(PPropInfo));
try
GetPropList(AObject.ClassInfo,PropList);
for PropIndex := 0 to PropCount - 1 do
begin
PropInfo := PropList^[PropIndex];
if Assigned(PropInfo^.SetProc) then
case PropInfo^.PropType^.Kind of
tkString,tkUString,tkWString:
SetStrProp(AObject,PropInfo,'');
tkEnumeration:
if GetTypeData(PropInfo^.PropType^)^.BaseType^ = TypeInfo(Boolean) then
SetOrdProp(AObject,0);
end;
end;
finally
FreeMem(PropList);
end;
end;
这是一个简单的测试代码(注意属性必须发布;如果类中没有已发布的属性,至少空的发布部分必须在那里)：
type
TSampleClass = class(TObject)
private
FStringProp: string;
FBooleanProp: Boolean;
published
property StringProp: string read FStringProp write FStringProp;
property BooleanProp: Boolean read FBooleanProp write FBooleanProp;
end;
procedure TForm1.Button1Click(Sender: TObject);
var
SampleClass: TSampleClass;
begin
SampleClass := TSampleClass.Create;
try
SampleClass.StringProp := 'This must be cleared';
SampleClass.BooleanProp := True;
ResetPropertyValues(SampleClass);
ShowMessage('StringProp = ' + SampleClass.StringProp + sLineBreak +
'BooleanProp = ' + BoolToStr(SampleClass.BooleanProp));
finally
SampleClass.Free;
end;
end;