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  • 你该知道的 TValue

    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

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  • 原文地址:https://www.cnblogs.com/cb168/p/5509690.html
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