如何在全屏表单后面捕获桌面屏幕截图

Question

>我有一个全屏表单来阻止所有输入。如何捕获此表单后面所有桌面的屏幕截图？换句话说，如何在不出现屏幕前的这种表格的情况下进行打印屏幕？

我正在编写一个远程访问软件。我需要在屏幕上显示技术支持信息，并在访问期间阻止所有输入，以便分析师安静地工作 - 例如 VNC 可以选择关闭显示器，Dameware 可以选择阻止输入。

还有另一种方法可以在此锁定屏幕后面远程工作？

Answer 1

虽然我完全同意评论者的观点，即使用全屏表单阻止用户输入不是一个好主意，但这里有一些代码可以帮助您入门。该代码假定屏幕尺寸为 1920 x 1200。

unit Unit152;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls;
type
  TForm152 = class( TForm )
    Timer1: TTimer;
    procedure Timer1Timer( Sender: TObject );
    procedure FormCreate( Sender: TObject );
  private
    { Private declarations }
    DesktopBMP: TBitmap;
    procedure WMEraseBkgnd( var Message: TWMEraseBkgnd ); message WM_ERASEBKGND;
  protected
    procedure Paint; override;
  public
    { Public declarations }
  end;
var
  Form152: TForm152;
implementation
{$R *.dfm}
{ TForm152 }
procedure TForm152.FormCreate( Sender: TObject );
begin
  DesktopBMP := TBitmap.Create;
  DesktopBMP.SetSize( 1920, 1200 );
end;
procedure TForm152.Paint;
begin
  inherited;
  Canvas.Draw( 0, 0, DesktopBMP );
end;
procedure TForm152.Timer1Timer( Sender: TObject );
begin
  // alternatively a simple Invalidate would do here, but then
  // all other windows would not redraw
  Width := 0;
  Height := 0;
  Width := 1920;
  Height := 1200;
end;
procedure TForm152.WMEraseBkgnd( var Message: TWMEraseBkgnd );
var
  DesktopDC: HDC;
  DesktopHwnd: Hwnd;
  DesktopCanvas: TCanvas;
begin
  DesktopHwnd := GetDesktopWindow;
  DesktopDC := GetDC( DesktopHwnd );
  try
    DesktopCanvas := TCanvas.Create;
    DesktopCanvas.Handle := DesktopDC;
    DesktopBMP.Canvas.CopyRect( Rect( 0, 0, 1919, 1199 ), DesktopCanvas, Rect( 0, 0, 1919, 1199 ) );
  finally
    DesktopCanvas.Free;
    ReleaseDc( DesktopHwnd, DesktopDC );
  end;
  Message.Result := 1;
  inherited;
end;
end.

DFM 如下所示：

object Form152: TForm152
  Left = 2296
  Top = 103
  BorderStyle = bsNone
  Caption = 'Form152'
  ClientHeight = 699
  ClientWidth = 1289
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  WindowState = wsMaximized
  OnCreate = FormCreate
  PixelsPerInch = 96
  TextHeight = 13
  object Timer1: TTimer
    Interval = 10
    OnTimer = Timer1Timer
    Left = 640
    Top = 360
  end
end