调用DLL窗体Delphi实例

（一）通过向导DLL Wizard新建一个动态链接库，取名为：DLLPro.dpr。说明：当在DLL工程文件中使用了String类型时，要有 uses ShareMem ，不过建议使用PChar类型。其代码如下：

library DLLPro;            //编译生成DLLPro.dll文件。

uses
ActiveX,
Forms,
Windows,
SysUtils,
Classes,
DLLUnt in 'DLLUnt.pas';

{$R *.res}

var
      DllApp:TApplication;    //全局变量DLLApp默认初始化，即，DLLApp:=Application.

procedure CreateForm1(app:TApplication;parentform: TForm); export;stdcall;
var
Form1: TForm1;
begin
CoInitialize(nil);
try
    Application:=app;
    Form1:=Tform1.Create(parentform);
    form1.MyParentForm:= parentform;         //MyParentForm在DLLUnt.pas中定义为公共变量
    form1.myparentApplication:=app;            //MyParentApplication在DLLUnt.pas中定义为公共变量

    Form1.Show;
    finally
      CoUninitialize;
    end;
end;

procedure ExitDll(Reason:Integer);
begin
if Reason = DLL_PROCESS_DETACH then                // DLL_PROCESS_DETACH值在DLL死亡时执行。
begin
    Application:=DllApp;
end;
end;

exports
CreateForm1;

begin
DllApp:=Application;       //该语句可以省略。
DllProc:=@ExitDll;          //变量DllProc是SysUtils单元的一个Pointer类型的变量。
end.

<===============================================================================>

（二）创建DLL（动态链接库）的单元文件，取名为：DLLUnt.pas，该单元文件有与其配套的窗体文件DLLUnt.dfm；有一个ADOConnection1组件，必须定义在TForm1类中，否则编译时出错：Access Violence其部分代码如下：

unit DLLUnt;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ExtCtrls, StdCtrls, Buttons,ADODB,DB;

type
TForm1 = class(TForm)
    Panel0: TPanel;
    GroupBox1: TGroupBox;
    Panel1: TPanel;
    Panel2: TPanel;

   ………………

    CheckBox891: TCheckBox;
    Edit1: TEdit;
    SpeedButton1: TSpeedButton;
    ADOConnection1: TADOConnection;
    procedure Edit1KeyPress(Sender: TObject; var Key: Char);
    procedure SpeedButton1Click(Sender: TObject);
    procedure Edit1Change(Sender: TObject);
private
    { Private declarations }
public
    { Public declarations }
    MyParentForm: TForm;
    MyParentApplication: TApplication;
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

………………

procedure TForm1.SpeedButton1Click(Sender: TObject);
var
   query:TADOquery;
   Count,I,RedNum,J,CheckNum:integer;
   RedName,LabName:string;
begin
if (edit1.Text='')or(length(edit1.Text)<7)or(StrToFloat(edit1.Text)<2008001) then
begin
showmessage('Error');
exit;
end;
query:=Tadoquery.Create(nil);
query.Connection:=ADOConnection1;
query.Close;
query.SQL.Clear;
query.SQL.Add('select * from gyWinNum where Id>='+quotedStr(edit1.Text)+' order by Id ');
query.Open;
Count:=1;
CheckNum:=0;
while (Not query.Eof)and(Count<28)   do

………………

end.

<===============================================================================>

（三）创建项目主窗体的工程文件，取名：MainForm.dpr，其代码如下：

program MainPro;               //编译生成MainPro.exe文件。

uses
Forms,
MainUnt in 'MainUnt.pas' {MainForm};

{$R *.res}

begin
Application.Initialize;
Application.CreateForm(TMainForm, MainForm);
Application.Run;
end.

<================================================================================>

（四）创建项目主窗体的单元文件，取名：MainUnt.pas，其代码如下：

unit MainUnt;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls,ADODB;                 //由于被调文件DLLPro.dll中含义数据集控件，在这里必须要有声明。

type
TMainForm = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  
private
    { Private declarations }
public
    { Public declarations }
end;

var
MainForm: TMainForm;

implementation
{$R *.dfm}

procedure CreateForm1(app: TApplication;parentform: TForm);stdcall; external'DLLPro.dll';

procedure TMainForm.Button1Click(Sender: TObject);
begin
      CreateForm1(Application,self);
end;

end.

<================================================================================>

另外：创建项目主窗体的单元文件，取名：MainUnt.pas，其代码也可以如下：

unit MainUnt;

interface

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

type
TMainForm = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  
private
    { Private declarations }
public
    { Public declarations }
end;
T_CreateForm1=procedure(app: TApplication;parentform: TForm);stdcall;     //定义T_CreateForm1类型

var
MainForm: TMainForm;

implementation
{$R *.dfm}

procedure TMainForm.Button1Click(Sender: TObject);
var
dllHandle: THandle;
Procaddr: FarProc;
CreateForm1: T_CreateForm1;
begin
    dllHandle:=LoadLibrary('DLLPro');
    Procaddr:=GetProcAddress(dllHandle,'CreateForm1');
    if Procaddr <> nil then
    begin
      CreateForm1:=procaddr;                      //过程名，标识它的入口地址，是过程指针。
      CreateForm1(Application,self);
    end;
end;

end.

到此为止，结束。