Dll创建一个"日历"窗体(一)

首先点击File->New->Other-> Dynamic Link Libary

把工程文件保存为:CalendarLib.pas 再创建一个Form并放入一个TMonthCalendar控件

borderStyle属性设为:bsToolWindow

保存为 DllFormUnit.pas

unit DllFormUnit;

interface

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

type
  TDllForm = class(TForm)
    MonthCalendar1: TMonthCalendar;
    procedure MonthCalendar1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  DllForm: TDllForm;

// 供外部调用函数

  function ShowCalendar(AHandle: THandle;ACaption: String):PChar;stdcall;

implementation

{$R *.dfm}
function ShowCalendar(AHandle: THandle;ACaption: String):PChar;
var
 DllForm: TDllForm;
begin
  //复制应用程序的句柄给Dll
  //Dll中Application对象与调用它的应用程序是分离的,为使Dll中的窗体真正的成
  //为应用程序模式窗体,必须将应用程序的句柄赋给Dll的Application.Handle属性
  //必须确保AHandle句柄不为nil,否则出现无法预料的错误
  Application.Handle := AHandle;
  DlLForm := TDllForm.Create(Application);
  try
     DllForm.Caption := ACaption;
     DllForm.ShowModal;
     Result := PChar(DateToStr(DllForm.MonthCalendar1.Date));
  finally
     DllForm.Free;
  end;
end;

procedure TDllForm.MonthCalendar1Click(Sender: TObject);
begin
  Close;
end;

end.

　CalendarLib.pas

library CalendarLib;

uses
  SysUtils,
  Classes,
  DllFormUnit in 'DllFormUnit.pas' {DllForm};

{$R *.res}
exports
  ShowCalendar;
begin
end.

　　

　

主窗体设计

MainFormUnit.pas文件

unit MainFormUnit;

interface

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

type
  TShowCalendar = function (AHandle: THandle;ACaption: String):PChar;stdcall;
  
  TMainForm = class(TForm)
    btnShowCalendar: TButton;
    lblDate: TLabel;
    procedure btnShowCalendarClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;

implementation

{$R *.dfm}

procedure TMainForm.btnShowCalendarClick(Sender: TObject);
var
 ShowCalendarForm: TShowCalendar;
 libHandle: THandle;
begin
   libHandle := LoadLibrary('CalendarLib.dll');
   try
      //是否读取成功
      if libHandle = 0 then
       raise Exception.Create('加载CalendarLib.dll失败');
       //读取函数方法地址
       @ShowCalendarForm := GetProcAddress(LibHandle,'ShowCalendar');
       //读取是否成功
       if not (@ShowCalendarForm = nil) then
       begin  
          lblDate.Caption :=ShowCalendarForm(Application.Handle,'选择日历');
       end
       else 
        RaiseLastWin32Error;
   finally

     //释放Dll     

     FreeLibrary(LibHandle);

DFM文件

object MainForm: TMainForm
  Left = 0
  Top = 0
  Caption = 'MainForm'
  ClientHeight = 202
  ClientWidth = 447
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object lblDate: TLabel
    Left = 119
    Top = 45
    Width = 98
    Height = 13
    Caption = #26085#26399':'
  end
  object btnShowCalendar: TButton
    Left = 16
    Top = 40
    Width = 97
    Height = 25
    Caption = #26174#31034#26085#21382#31383#20307
    TabOrder = 0
    OnClick = btnShowCalendarClick
  end
end

运行结果: