EnableTaskWindows，DisableTaskWindows

Posted 2020-12-26 jspdelphi

EnableTaskWindows

DisableTaskWindows

在Delphi中显示一个窗口有两种方式,模态方式显示（ShowModal）和非模态方式显示（Show），模态方式显示窗口时,必须在自身关闭后才能使父窗口起作用，但有时我们想要实现一个窗口,既要具有模态窗口的特性，但又要能从父窗口中控制它，如显示一个表示处理进行过程的进度框。利用DisableTaskWindows和 EnableTaskWindows 可以达到这一效果。

 

下面是在程序里中的一个小应用，删除选中数据。可以避免删除过程中，更新选中状态造成的错误。

窗体注意

    1. Position = poMainFormCenter

    2.CloseQuery事件中控制窗体是否能关闭

==============================================================================

object Fprogress: TFprogress

Left = 756

Top = 497

BorderIcons = []

BorderStyle = bsDialog

Caption = ‘Fprogress‘

ClientHeight = 80

ClientWidth = 262

Color = clBtnFace

Font.Charset = DEFAULT_CHARSET

Font.Color = clWindowText

Font.Height = -11

Font.Name = ‘Tahoma‘

Font.Style = []

OldCreateOrder = False

Position = poMainFormCenter

OnCloseQuery = FormCloseQuery

PixelsPerInch = 96

TextHeight = 13

object ProgressBar1: TProgressBar

Left = 29

Top = 34

Width = 209

Height = 17

TabOrder = 0

end

end

=============================================================================

unit pprogress;

 

interface

 

uses

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

Dialogs, ComCtrls;

 

type

TFprogress = class(TForm)

ProgressBar1: TProgressBar;

procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);

private

Fwlist: Pointer;

public

 

/// <summary>

/// 显示进度窗口

/// </summary>

/// <param name="ACaption">标题</param>

/// <returns>THandle</returns>

class function ShowM(ACaption: string): THandle;

 

/// <summary>

/// 更新进度条

/// </summary>

/// <param name="value">位置</param>

/// <returns>None</returns>

class procedure Position(value: Integer);

 

/// <summary>

/// 关闭进度窗口

/// </summary>

/// <returns>None</returns>

class procedure CloseM;

end;

 

var

Fprogress: TFprogress;

 

implementation

 

{$R *.dfm}

 

var

LcanClose: Boolean = false;

{ TFprogress }

 

class procedure TFprogress.CloseM;

begin

LcanClose := True;

EnableTaskWindows(Fprogress.Fwlist);

Fprogress.Close;

end;

 

class procedure TFprogress.Position(value: Integer);

begin

Fprogress.ProgressBar1.Position := value;

end;

 

class function TFprogress.ShowM(ACaption: string): THandle;

begin

Fprogress := TFprogress.Create(nil);

Fprogress.ProgressBar1.Position := 0;

Fprogress.Caption := ACaption;

LcanClose := False;

Result := Fprogress.Handle;

Fprogress.Fwlist := DisableTaskWindows(Result);

Fprogress.Show;

end;

 

procedure TFprogress.FormCloseQuery(Sender: TObject;

var CanClose: Boolean);

begin

CanClose := LcanClose;

end;

 

end.