Sub Window – 蓝天白云

在子窗口中重载CreateParams函数，并将WndParent设置为0即可，具体代码如下：

unit Unit2;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs;

type
  TForm2 = class(TForm)
  private
    { Private declarations }
  public
    { Public declarations }
  protected
    //重载此函数
    procedure CreateParams(var Params: TCreateParams); Override;
  end;

var
  Form2: TForm2;

implementation

{$R *.dfm}

procedure TForm2.CreateParams(var Params: TCreateParams);
begin
  inherited;
  With Params do begin
    WndParent := 0;
  end;
end;

end.

unit Unit2;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs;

type

TForm2 = class(TForm)

private

{ Private declarations }

public

{ Public declarations }

protected

//重载此函数

procedure CreateParams(var Params: TCreateParams); Override;

end;

var

Form2: TForm2;

implementation

{$R *.dfm}

procedure TForm2.CreateParams(var Params: TCreateParams);

begin

inherited;

With Params do begin

WndParent := 0;

end;

end.

当我们把Params.WndParent设置为0时，Delphi在调用CreateWindowEx创建该窗口时，会将hWndParent 参数设置为相同的值（此处为0），为0则意味着要创建的窗口的所有者为桌面。此值不能在运行期通过Windows ApI改变，可能是因为窗口的拥有者不能在运行期改变的原因。

一些有用的链接

CreateWindowEx function

MFC子窗口和父窗口（SetParent,SetOwner）