如何通过程序动态加载.DLL文件，如何卸载.DLL，卸载后有可以随时加载

Question

如何通过程序动态加载.DLL文件，如何卸载.DLL，卸载后有可以随时加载

Answer 1

静态加载:Function 函数名(参数):返回值cdecl;external '路径+动态库名';
动态加载:需要三个函数loadlibrary、Getprocess、Freelibrary即可.

Answer 2

delphi建立dll
cb调用dll，type __fastcall type...cb建立dll
delphi调用dll，function...: type; cdecl;谁知道vc开发的dll，调用时用什么修饰？

Answer 3

采用动态调用DLL时，可以用全局方式，先将其放在申明UNIT中，在程序创建调用初始化，
结束时释放。
//DLL申明UNIT dllclear.pas
unit dllclear;interfaceuses
  Windows, SysUtils, hydeclear, libcs;type
  Thyclient = Record
    libload:Boolean;
    connected:Boolean;
    hyclient:THandle;
    apSendstrToHost:TFarproc;
    apConnectToHost:TFarproc;
    apDisConnectToHost:TFarproc;
    apNetWatchOption:TFarproc;
end;type
  TNetWatchOption = function ():boolean;
  TSendstrToHost = function (sendstr:string):boolean;
  TConnectToHost = function ():boolean;
  TDisConnectToHost = function ():boolean;
Function HyClientInit:boolean;
Function HyClientDestroy:boolean;var
  hyclient:Thyclient;implementationFunction HyClientInit:boolean;
begin
  try
    hyclient.hyclient:=Loadlibrary('hyclient.dll');
    hyclient.apNetWatchOption:=GetprocAddress(hyclient.hyclient,'NetWatchOption');
    hyclient.apSendstrToHost:=GetprocAddress(hyclient.hyclient,'SendstrToHost');
    hyclient.apConnectToHost:=GetprocAddress(hyclient.hyclient,'ConnectToHost');
    hyclient.apDisConnectToHost:=GetprocAddress(hyclient.hyclient,'DisConnectToHost');
    if hyclient.hyclient>0 then
      begin
        hyclient.libload:=True;
        Result:=True;
      end
    else
      begin
        hyclient.libload:=False;
        hyclient.connected:=False;
        Result:=False;
      end;
  except
    Result:=False;
  end;
end;Function HyClientDestroy:boolean;
begin
  try
    FreeLibrary(hyclient.hyclient);
    hyclient.libload:=False;
    hyclient.connected:=False;
    Result:=True;
  except
    Result:=False;
  end;
end;end.主程序调用
procedure Form.OnCreate(Sender:TObject);
begin
   if fileexists('hyclient.dll') then
    begin
       if not HyclientInit then
          ShowError('网络监测库初始化失败！');
    end;
 end;procedure Form.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  if hyclient.libload then
    hyclientdestroy;
 end; 

Answer 4

procedure TForm1.Button1Click(Sender: TObject); type TIntFunc=function(i:integer):integer;stdcall; var Th:Thandle; Tf:TIntFunc; Tp:TFarProc; begin Th:=LoadLibrary(’Cpp.dll’); {装载DLL} if Th>0 then try Tp:=GetProcAddress(Th,PChar(’TestC’)); if Tp<>nil then begin Tf:=TIntFunc(Tp); Edit1.Text:=IntToStr(Tf(1)); {调用TestC函数} end else ShowMessage(’TestC函数没有找到’); finally FreeLibrary(Th); {释放DLL} end else ShowMessage(’Cpp.dll没有找到’); end;