Delphi XE3 indy 10 UDP

Question

我想创建一个客户端服务器UDP。问题在于，服务器不能mopulit图片

type 
    TPacket = record 
    Image: TJPEGImage; 
    student: string; 
    end; 

var 
    Image: TBitmap; 
    Desktop: TDesktop; 
    by: TBytes; 
    Packet: TPacket; 

implementation 

{$R *.dfm} 

procedure TDesktop.Button1Click(Sender: TObject); 
var 
    can: TCanvas; 
begin 
    can := TCanvas.Create; 
    can.Handle := GetWindowDC(GetDesktopWindow); 
    ZeroMemory(by, 0); 
    Packet.Image := TJPEGImage.Create; 
    Image := TBitmap.Create; 
    Image.Width := Screen.Width; 
    Image.Height := Screen.Height; 
    Image.Canvas.CopyRect(
    Rect(0, 0, Screen.Width, Screen.Height), 
    can, 
    Rect(0, 0, Screen.Width, Screen.Height) 
); 
    Packet.Image.Assign(Image); 
    Packet.Image.CompressionQuality := 50; 
    Packet.student := 'student'; 
    IdUDPClient1.BufferSize := SizeOf(packet); 
    SetLength(by, sizeof(packet)); 
    Move(packet, by[0], sizeof(packet)); 
    IdUDPClient1.SendBuffer('127.0.0.1', 5, by); 
    Image.Free; 
    Packet.Image.Free; 
    ReleaseDC(0, can.Handle); 
end; 

procedure TDesktop.FormShow(Sender: TObject); 
begin 
    IdUDPServer1.BufferSize:=SizeOf(packet); 
end; 

procedure TDesktop.IdUDPServer1UDPRead(AThread: TIdUDPListenerThread; 
    AData: array of Byte; ABinding: TIdSocketHandle); 
begin 
    Packet.Image := TJPEGImage.Create; 
    Move(AData[0], packet, sizeof(AData)); 
    Caption := Packet.student; 
    Packet.Image.SaveToFile('E:\1.jpg'); 
    Packet.Image.Free; 
end; 

Answer 1

你​​包含一个对象指针和动态分配的字符串。你不能原样传输这些值到另一台机器，甚至在同一台机器上的另一个进程。您必须必须将值序列化为原始字节，然后发送和接收字节，然后将字节反序列化为接收端上的可行数据。

尝试更多的东西是这样的：

procedure ScreenshotToJpgStream(Stream: TStream); 
var 
    R: TRect; 
    can: TCanvas; 
    dc: HDC; 
    Bmp: TBitmap; 
    Jpg: TJPEGImage; 
begin 
    R := Rect(0, 0, Screen.Width, Screen.Height); 
    Jpg := TJPEGImage.Create; 
    try 
    Bmp := TBitmap.Create; 
    try 
     Bmp.Width := R.Width; 
     Bmp.Height := R.Height; 
     can := TCanvas.Create; 
     try 
     dc := GetWindowDC(0); 
     can.Handle := dc; 
     try 
      Bmp.Canvas.CopyRect(R, can, R); 
     finally 
      can.Handle := 0; 
      ReleaseDC(0, dc); 
     end; 
     finally 
     can.Free; 
     end; 
     Jpg.Assign(Bmp); 
    finally 
     Bmp.Free; 
    end; 
    Jpg.CompressionQuality := 50; 
    Jpg.SaveToStream(Stream); 
    finally 
    Jpg.Free; 
    end; 
end; 

procedure TDesktop.Button1Click(Sender: TObject); 
var 
    ImageStrm: TBytesStream; 
    Student: String; 
    Packet: TIdBytes; 
    Offset, ImageLen, StudentLen: Integer; 
begin 
    ImageStrm := TBytesStream.Create; 
    try 
    ScreenshotToJpgStream(ImageStrm); 
    ImageLen := ImageStrm.Size; 

    Student := 'student'; 
    StudentLen := TIdTextEncoding.UTF8.GetByteCount(Student); 

    SetLength(Packet, (SizeOf(Integer)*2) + ImageLen + StudentLen); 
    Offset := 0; 

    CopyTIdLongInt(ImageLen, Packet, Offset); 
    Inc(Offset, 4); 
    CopyTIdByteArray(ImageStrm.Bytes, 0, Packet, Offset, ImageLen); 
    Inc(Offset, ImageLen); 
    CopyTIdLongInt(StudentLen, Packet, Offset); 
    Inc(Offset, 4); 
    CopyTIdString(Student, Packet, Offset, -1, TIdTextEncoding.UTF8); 
    finally 
    ImageStrm.Free; 
    end; 

    IdUDPClient1.SendBuffer('127.0.0.1', Port, Packet); 
end; 

procedure TDesktop.IdUDPServer1UDPRead(AThread: TIdUDPListenerThread; 
    AData: array of Byte; ABinding: TIdSocketHandle); 
type 
    PIdBytes = ^TIdBytes; 
var 
    ImageStrm: TIdMemoryStream; 
    Student: String; 
    Offset, Len: Integer; 
begin 
    Offset := 0; 

    Len := BytesToLongInt(PIdBytes(@AData)^, Offset); 
    Inc(Offset, 4); 

    Assert(Length(AData) >= (Offset+Len)); 

    ImageStrm := TIdMemoryStream.Create(@AData[Offset], Len); 
    try 
    Inc(Offset, Len); 

    Len := BytesToLongInt(PIdBytes(@AData)^, Offset); 
    Inc(Offset, 4); 
    Student := BytesToString(PIdBytes(@AData)^, Offset, Len, TIdTextEncoding.U2TF8); 

    Caption := Student; 
    Jpg := TJPEGImage.Create; 
    try 
     Jpg.LoadFromStream(ImageStrm); 
     Jpg.SaveToFile('E:\1.jpg'); 
    finally 
     Jpg.Free; 
    end; 
    finally 
    ImageStrm.Free; 
    end; 
end;