_NET Compact Framework下的进程间通信之Windows Message.doc

.NET Compact Framework下的进程间通信之Windows Message在Wince和Windows Moblie 下的进程间通信可以由以下几种技术实现。1. Windows Message2. Point-to-Point Message Queues3. MSMQ下面使用讲述.NET Compact Framework下使用Windows Message进行进程间的通信。引用库在CF.net下进行Windows Message的开发需要引用Microsoft.WindowsCE.Forms，该DLL一般存放于C:Program FilesMicrosoft.NETSDKCompactFrameworkv2.0WindowsCEMicrosoft.WindowsCE.Forms.dll发送消息usingMicrosoft.WindowsCE.Forms;publicpartialclassMsgForm:FormDllImport(coredll.dll,EntryPoint=RegisterWindowMessage,SetLastError=true)privatestaticexternuintRegisterWindowMessage(stringlpString);privateuintmsgUid=RegisterWindowMessage(MESSAGE_UID);public static int MSG_BROADCAST = 0xFFFF;privatevoidSendMessage(objectsender)Messagemsg=Message.Create(IntPtr)MSG_BROADCAST,(int)msgUid,IntPtr.Zero,IntPtr.Zero);MessageWindow.SendMessage(refmsg);首先需要P/Invoke RegisterWindowMessage 函数，每个发送的message都有唯一的UID，这样接收方才能根据UID进行监听和接收该Message。发送之前先create一个Message对象，参数一为接收对象，如果为进程间通信可以使用广播的形式（MSG_BROADCAST），第二个参数为message的UID，接收方利用这一表示辨别message。第三和第四分别为WParam和LParam，这是标准windows message的传递参数。接收消息usingMicrosoft.WindowsCE.Forms;publicclassMsgWindow:MessageWindow DllImport(coredll.dll,EntryPoint=RegisterWindowMessage,SetLastError=true)privatestaticexternuintRegisterWindowMessage(stringlpString);privateuintmsgUid=RegisterWindowMessage(MESSAGE_UID);protectedoverridevoidWndProc(refMessagemsg)if(msg.Msg=msgUid)/handlethemessage. 接收消息需要定义一个继承类，继承于MessageWindow，同时他同样需要P/Invoke RegisterWindowMessage 函数，定义接收message的唯一UID。重写WndProc，然后通过msg.Msg 来辨别关心的消息。使用Form处理Message如果接收方接收到message需要更新到form的话就定义一个form的reference，这样可以利用form来处理消息。其实不一定使用Form来处理message，使用Form就能比较方便的利用ui来反映message的接收和处理情况。publicpartialclassMsgForm:FormprivateMsgWindowMsgWin;publicMsgForm() /passtheformreferencetomessagewindowthis.MsgWin=newMsgWindow(this);publicclassMsgWindow:MessageWindowprivateMsgFormmsgForm;publicMsgWindow(MsgFormmsgForm) this.msgForm=msgForm; protectedoverridevoidWndProc(refMessagemsg) if(msg.Msg=msgUid) /callformtohandlethemessage. msgForm.HandleMsg(); MsgWindow 保存MsgForm 的引用，这样当MsgWindow 接收到消息就可以使用form来处理。消息中传递对象如果在消息中传递对象，就不可以使用.NET Compact Framework里面的MessageWindow.SendMessage函数了，需要使用P/Invoke来进行发送。发送端的关键是把要传递的对象封装到COPYDATASTRUCT Structure里面，然后通过APISendMessageW进行发送，接收方辨别WM_COPYDATA消息，从LParam中分拆出对象。 publicstructCOPYDATASTRUCTpublicintdwData;publicintcbData;publicIntPtrlpData;classcMsgStringsconstintLMEM_FIXED=0x0000;constintLMEM_ZEROINIT=0x0040;constintLPTR=(LMEM_FIXED|LMEM_ZEROINIT);constintWM_COPYDATA=0x004A;DllImport(coredll.dll)publicstaticexternIntPtrLocalAlloc(intflag,intsize);DllImport(coredll.dll)publicstaticexternIntPtrLocalFree(IntPtrp);DllImport(coredll.dll)publicstaticexternintSendMessageW(IntPtrhWnd,intMsg,IntPtrwParam,IntPtrlParam);publicstaticIntPtrAllocHGlobal(intcb)IntPtrhMemory=newIntPtr();hMemory=LocalAlloc(LPTR,cb);returnhMemory;publicstaticvoidFreeHGlobal(IntPtrhMemory)if(hMemory!=IntPtr.Zero)LocalFree(hMemory);publicstaticvoidSendMsgString(IntPtrhWndDest,stringsScript)COPYDATASTRUCToCDS=newCOPYDATASTRUCT();oCDS.cbData=(sScript.Length+1)*2;oCDS.lpData=LocalAlloc(LPTR,oCDS.cbData);Marshal.Copy(sScript.ToCharArray(),0,oCDS.lpData,sScript.Length);oCDS.dwData=1;IntPtrlParam=AllocHGlobal(oCDS.cbData);Marshal.StructureToPtr(oCDS,lParam,false);SendMessageW(hWndDest,WM_COPYDATA,IntPtr.Zero,lParam);LocalFree(oCDS.lpData);FreeHGlobal(lParam);/sendthemessagewithstringprivatevoidbutton1_Click(objectsender,EventArgse)unsafecMsgStrings.SendMsgString(IntPtr)MSG_BROADCAST,textBoxMsg.Text);上面为发生端的代码，通过cMsgStrings.SendMsgString进行发送，可以把任何managed的object封装到COPYDATASTRUCT 进行发送。publicclassMsgWindow:MessageWindowconstintWM_COPYDATA=0x004A;privateFormReceivermsgForm;publicMsgWindow(FormReceivermsgForm)this.msgForm=msgForm;protectedoverridevoidWndProc(refMessagemsg)if(msg.Msg=WM_COPYDATA)stringstr=GetMsgString(msg.LParam);msgForm.HandleMsg(str);publicstaticstringGetMsgString(IntPtrlParam)if(lParam!=IntPtr.Zero)COPYDATASTRUCTst=(COPYDATASTRUCT)Marshal.PtrToStructure(lParam,typeof(COPYDATASTRUCT);stringstr=Marshal.PtrToStringUni(st.lpData);returnstr;elsereturnnull;上面为接收端的代码，辨别WM_COPYDATA的消息从LParam中取出传递的对象。taob tbw BB霜 BB霜 CC霜 CC霜 www.qii.c