大侠帮一下刚摸到DELPHI门的人把！关于DLL(50分)

northwindrocker · 2003-09-23

我看《d6编程人员指南》中对把FORM做成DLL调用的例子！书中讲到的是把日历做为一个DLL然后在主程序里调用。源码如下： Calendarlib.drp {*******************************************} library CalendarLib; uses   ShareMem,   SysUtils,   Classes,   DLLFrm in 'DLLFrm.pas' {DLLForm}; exports   ShowCalendar;   begin end. {********************************} Dllfrm.pas {********************************} { Copyright ?2001 Delphi 6 Developer's Guide Xavier Pacheco   and Steve Teixeira } unit DLLFrm; interface uses   SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,   Forms, Dialogs, Grids, Calendar; type   TDLLForm = class(TForm)     calDllCalendar: TCalendar;     procedure calDllCalendarDblClick(Sender: TObject);   end; { Declare the export function } function ShowCalendar(AHandle: THandle; ACaption: String): TDateTime; StdCall; implementation {$R *.DFM} function ShowCalendar(AHandle: THandle; ACaption: String): TDateTime; var   DLLForm: TDllForm; begin   // Copy application handle to DLL's TApplication object   Application.Handle := AHandle;   DLLForm := TDLLForm.Create(Application);   try     DLLForm.Caption := ACaption;     DLLForm.ShowModal;     Result := DLLForm.calDLLCalendar.CalendarDate; // Pass the date back in Result   finally     DLLForm.Free;   end; end; procedure TDLLForm.calDllCalendarDblClick(Sender: TObject); begin   Close; end; end. 然后是主程序： CalendarTest.drp mainfrm { Copyright ?2001 Delphi 6 Developer's Guide Xavier Pacheco   and Steve Teixeira } unit MainFfm; interface uses   SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,   Forms, Dialogs, StdCtrls; type   { First, define a procedural data type, this should reflect the     procedure that is exported from the DLL. }   TShowCalendar = function (AHandle: THandle; ACaption: String): TDateTime; StdCall;   { Create a new exception class to reflect a failed DLL load }   EDLLLoadError = class(Exception);   TMainForm = class(TForm)     lblDate: TLabel;     btnGetCalendar: TButton;     procedure btnGetCalendarClick(Sender: TObject);   end; var   MainForm: TMainForm; implementation {$R *.DFM} procedure TMainForm.btnGetCalendarClick(Sender: TObject); var   LibHandle   : THandle;   ShowCalendar: TShowCalendar; begin   { Attempt to load the DLL }   LibHandle := LoadLibrary('CALENDARLIB.DLL');   try     { If the load failed, LibHandle will be zero.       If this occurs, raise an exception. }     if LibHandle = 0 then       raise EDLLLoadError.Create('Unable to Load DLL');     { If the code makes it here, the DLL loaded successfully, now obtain       the link to the DLL's exported function so that it can be called. }     @ShowCalendar := GetProcAddress(LibHandle, 'ShowCalendar');     { If the function is imported successfully, then set lblDate.Caption to reflect       the returned date from the function. Otherwise, show the return raise       an exception. }     if not (@ShowCalendar = nil) then       lblDate.Caption := DateToStr(ShowCalendar(Application.Handle, Caption))     else       RaiseLastWin32Error;                                                                 finally     FreeLibrary(LibHandle); // Unload the DLL.   end; end; end. 然后我编译DLL运行主程序报内存错误，但程序还是能运行。我估计是他的caption用了string的原因（很肤浅不要笑我）。我不知道怎么改它。能帮我看看吗！

kimlon · 2003-09-23

将string改为widestring就可以了

雪中漫步 · 2003-09-23

string 改成pchar!

northwindrocker · 2003-09-23

我试过改为pchar但是没改好，改的程序完全不能动了，我就是把用到string变量的地方改为PCHAR但是在主程序里面过不去。哪位好心的人改一下源码贴上来吧！谢谢！

zyfang · 2003-09-23

静态链接不会出错： type  TMainForm = class(TForm)    lblDate: TLabel;    btnGetCalendar: TButton;    procedure btnGetCalendarClick(Sender: TObject);  end; var  MainForm: TMainForm;  function ShowCalendar(AHandle: THandle; ACaption: string): TDate;StdCall; external 'CALENDARLIB.DLL'; implementation {$R *.DFM} procedure TMainForm.btnGetCalendarClick(Sender: TObject); begin      lblDate.Caption := DateToStr(ShowCalendar(Application.Handle, Caption)); end;

zfsfj · 2003-09-23

DLLForm.ShowModal;    //这时Dllform是不是已经被free掉了?下面再取DllForm里的值当然会报错了    Result := DLLForm.calDLLCalendar.CalendarDate;

zqw0117 · 2003-09-23

在你的dll的.dpr文件里面的use语句下面，第一行写ShareMem，然后再在你的工程（exe文 件）的dpr文件里面的use语句下面的第一行也写上ShareMem。这样就不会有问题了。注意， 我说的是dpr文件，不是pas文件。

northwindrocker · 2003-09-23

我试试!

大侠帮一下刚摸到DELPHI门的人把！关于DLL(50分)

northwindrocker

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northwindrocker

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northwindrocker

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