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。