delphi - 为什么我在使用 TStream 类时收到 "Abstract Error"？

Question

当我尝试运行以下简单代码序列时，收到Abstract Error 错误消息:

type
  TForm1 = class(TForm)
    Image1: TImage;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

procedure TForm1.Button1Click(Sender: TObject);
var
  ImageStream: TStream;
begin
  ImageStream := TStream.Create;
  Image1.Picture.Bitmap.SaveToStream(ImageStream);
  ...
end;

我需要提取 TBitmap 的流以供以后处理...我做错了什么？

Answer 1

TStream class是一个抽象类，是所有流的基础。

TStream is the base class type for stream objects that can read from or write to various kinds of storage media, such as disk files, dynamic memory, and so on.

Use specialized stream objects to read from, write to, or copy information stored in a particular medium.

您可能想使用TMemoryStream或TFileStream ，顾名思义，它将流内容存储在内存或系统文件中。

procedure TForm1.Button1Click(Sender: TObject);
var
  ImageStream: TMemoryStream;
begin
  ImageStream := TMemoryStream.Create;
  try
    Image1.Picture.Bitmap.SaveToStream(ImageStream);
    ...
  finally
    ImageStream.Free;
  end;
end;