我在写Mis系统时，将子窗体封状在DLL中，但子窗体不能接收键盘消息。如在子窗体上放三个EDIT，当打开该子窗体时，按TAB键会跳到MDI的空间上，而不是在子窗体中的Edit中切换。 1.在M DI中放一按钮调用DLL,源代码如下： unit UFrmMain; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls, DB, DBClient, MConnect, SConnect, Grids, DBGrids, WinSkinData, ComCtrls, dxtree; const wm_FreeDll=wm_User $10; type TDllFun = function(App : TApplication; SConn : TSocketConnection) : TForm;//定义了一个函数类型 TForm1 = class(TForm) Button1: TButton; SocketConnection1: TSocketConnection; SkinData1: TSkinData; Edit1: TEdit; dxTreeView1: TdxTreeView; Panel1: TPanel; procedure Button1Click(Sender: TObject); private DllHandle : THandle; DllFrm : TForm; Procedure FreeDll(var Msg : TMessage);Message wm_FreeDll; { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation {$R *.dfm} //按钮调用DLL procedure TForm1.Button1Click(Sender: TObject); Var DllFun : TDllFun; FarProc : TFarProc; begin DllHandle := LoadLibrary(PAnsiChar(ExtractFilePath(Application.ExeName) ’QGC.DLL’)); if DllHandle>0 then begin Try FarProc := GetProcAddress(DllHandle,'ShowForm'); if Assigned(FarProc) then begin DllFun := TDllFun(FarProc); DllFrm := DllFun(Application,SocketConnection1); //DLlFrm.ParentWindow := self.Panel1.Handle; //DLlFrm.Align := alClient; Try DllFrm.Show; Finally {DllFrm.Free; DllFrm:=Nil;} end; end else Raise Exception.Create('接口函数不正确！'); Finally {FreeLibrary(DllHandle); DllHandle:=0;} end; end else Raise Exception.Create('没找到文件'); end; {子窗体退出处理} procedure TForm1.FreeDll(var Msg: TMessage); begin ShowMessage('1'); if DllFrm<>nil then begin Try DllFrm.Free; DllFrm:=Nil; Finally FreeLibrary(DllHandle); DllHandle:=0; end; end; end; end. //QGC.DLL源码 ibrary Qgc; { Important note about DLL memory management: ShareMem must be the first unit in your library's USES clause AND your project's (select Project-View Source) USES clause if your DLL exports any procedures or functions that pass strings as parameters or function results. This applies to all strings passed to and from your DLL--even those that are nested in records and classes. ShareMem is the interface unit to the BORLNDMM.DLL shared memory manager, which must be deployed along with your DLL. To avoid using BORLNDMM.DLL, pass string information using PChar or ShortString parameters. } uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, DB, DBClient, MConnect, SConnect,WinSkinData, UDllChildFrm in 'UDllChildFrm.pas' {DllChildFrm}; {$R *.res} Var OldApp : TApplication; {接口函数} Function ShowForm(App : TApplication; SConn : TSocketConnection): TForm; begin Application := App; Result := TDllChildFrm.Create(Application); TDllChildFrm(Result).SocketConn := SConn; end; procedure ExitDll(Reason : integer); begin if Reason = DLL_PROCESS_DETACH then Application := OldApp; end; DLL封装的窗体代码 unit UDllChildFrm; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, DB, DBClient, MConnect, SConnect, Grids, DBGrids, ExtCtrls, DBCtrls, dxsbar, WinSkinData; const wm_FreeDLl=wm_user $10; type TDllChildFrm = class(TForm) DataSource1: TDataSource; ClientDataSet: TClientDataSet; ClientDataSetBDCODE: TStringField; ClientDataSetBDNAME: TStringField; ClientDataSetBDLB: TStringField; ClientDataSetPARENTID: TStringField; ClientDataSetZGXLBD: TStringField; ClientDataSetZGCK: TStringField; ClientDataSetNO: TIntegerField; Splitter1: TSplitter; Edit1: TEdit; Edit2: TEdit; Edit3: TEdit; procedure FormClose(Sender: TObject; var Action: TCloseAction); procedure FormShow(Sender: TObject); procedure Button1Click(Sender: TObject); procedure Button3Click(Sender: TObject); procedure Button4Click(Sender: TObject); procedure ClientDataSetCalcFields(DataSet: TDataSet); private { Private declarations } public SocketConn : TSocketConnection; { Public declarations } end; var DllChildFrm: TDllChildFrm; implementation {$R *.dfm} procedure TDllChildFrm.FormClose(Sender: TObject; var Action: TCloseAction); begin //Action := caHide; PostMessage(Application.MainForm.Handle,wm_FreeDll,0,0); end; procedure TDllChildFrm.FormShow(Sender: TObject); begin ClientDataSet.RemoteServer := SocketConn; ClientDataSet.ProviderName := 'p_select'; ClientDataSet.CommandText := 'Select * From GuideItem'; ClientDataSet.Open; ClientDataSet.First; end; procedure TDllChildFrm.Button1Click(Sender: TObject); begin Close; end; procedure TDllChildFrm.Button3Click(Sender: TObject); begin ClientDataSet.Insert; end; procedure TDllChildFrm.Button4Click(Sender: TObject); begin ClientDataSet.Delete; end; procedure TDllChildFrm.ClientDataSetCalcFields(DataSet: TDataSet); begin DataSet.FieldByName('NO').AsInteger := DataSet.RecNo; end; end.