你该知道的 TValue

Represents a lightweight version of the Variant type.

TValue is a data structure that can store different kinds of data types. TValue is used in the Rtti unit to ease the access to fields and method parameters.

 

System.Rtti

var  av: TValue;begin  av.AsInteger;  av.AsString;

var

  av: TValue;

  akind: TTypeKind;

begin

  av := 8;

  av.TypeData;

  akind := av.TypeInfo.Kind;//变量类型

  self.Caption := av.TypeInfo.Name;//变量类型名称

  av.AsInteger;

  av.AsString;

    if not Value.IsEmpty then

      if Value.IsType<string> then

if Value.IsType<TBitmapSurface> then

Bitmap.Assign(Value.AsType<TBitmapSurface>);

Value.AsType<TBitmapSurface>.Free;

 

  ov: OleVariant;

  tv: TValue;

 ov := 'hello';

  tv := TValue.From<OleVariant>(ov);

  self.Caption := tv.AsString;

 tv := TValue.FromVariant(ov);

TValue.From<String>

TValue.From<Boolean>

学习

http://www.cnblogs.com/hezihang/p/3280470.html