C#中调用WINDOWS API(RegisterDragDrop)失败,不知是何原因?谁能解决,100分全给他

Question

C#中调用WINDOWS API(RegisterDragDrop)失败,不知是何原因?
        [DllImport("ole32.dll")]
        static extern int RegisterDragDrop(IntPtr hwnd, IDropTarget pDropTarget);        public Form1()
        {
            InitializeComponent();
            hwnd = FindWindowEx(GetDesktopWindow(), IntPtr.Zero, "Shell_TrayWnd", "");
            hwnd = FindWindowEx(hwnd, IntPtr.Zero, "TrayNotifyWnd", "");
            hwnd = FindWindowEx(hwnd, IntPtr.Zero, "SysPager", "");
            //hwnd = FindWindowEx(hwnd, 0, "ToolbarWindow32", "");
            dt = new DropTarget();
            int result = RegisterDragDrop(hwnd, dt);
            if (result != 0)
            {
                String info = String.Format("RegisterDragDrop failed {0:X}", hwnd);
                MessageBox.Show(info);
            }
        }谁有调用成功的代码,100分全归他了

Answer 1

//---------------------------------------------------------------------------#include <vclmax.h>
#pragma hdrstop#include "Dropmain.h"//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
#define WM_MYMESSAGE    (0x0400+100)
#define WM_CLOSEMESSAGE (0x0400+101)
#define WM_COPYDATA2    (0x004A)
TfrmDropmain *frmDropmain;class CDropTarget : public IDropTarget
{
    public:
    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void**ppvObject)
    {
        if (riid == IID_IUnknown || riid == IID_IDropTarget)
        {
            *ppvObject = this;
            return S_OK;
        } else {
            *ppvObject = 0;
            return E_NOINTERFACE;
        }
    }    ULONG STDMETHODCALLTYPE AddRef( void)
    {
        return S_OK;
    }    ULONG STDMETHODCALLTYPE Release( void)
    {
        return S_OK;
    }    HRESULT STDMETHODCALLTYPE DragEnter(IDataObject *pDataObj, DWORD grfKeyState, POINTL pt, DWORD *pdwEffect)
    {
        //Form1->Memo1->Lines->Add("DragEnter");
        return S_OK;
    }    HRESULT STDMETHODCALLTYPE DragOver(DWORD grfKeyState, POINTL pt, DWORD *pdwEffect)
    {
        //Form1->Memo1->Lines->Add("DragOver");
        return S_OK;
    }    HRESULT STDMETHODCALLTYPE DragLeave( void)
    {
        //Form1->Memo1->Lines->Add("DragLeave");
        return S_OK;
    }    HRESULT STDMETHODCALLTYPE Drop(IDataObject *pDataObj, DWORD grfKeyState, POINTL pt, DWORD *pdwEffect)
    {
        IEnumFORMATETC* pEnum = 0;
        HRESULT hr = pDataObj->EnumFormatEtc(DATADIR_GET, &pEnum);
        if (hr != S_OK)
            return hr;        FORMATETC formatEtc={CF_TEXT,0,DVASPECT_CONTENT,-1,DWORD(-1)};
        if (pDataObj->QueryGetData(&formatEtc)== S_OK)
        {            STGMEDIUM Stg;            BOOL bValue=(pDataObj->GetData(&formatEtc,&Stg)==S_OK);
            if(bValue)
            {
                AnsiString asUrl = (char*)GlobalLock(Stg.hGlobal);                HWND hw = FindWindow(NULL,"Gadget Server");
                COPYDATASTRUCT cdsUrl;
                cdsUrl.lpData = asUrl.c_str();
                cdsUrl.cbData = asUrl.Length() + 1;
//ShowMessage(AnsiString(asUrl.c_str()));
                SendMessage(hw,WM_COPYDATA2,WPARAM(0),LPARAM(&cdsUrl));
                frmDropmain->Memo1->Lines->Add(asUrl);
                GlobalUnlock(Stg.hGlobal);
                GlobalFree(Stg.hGlobal);
            }
        }        return S_OK;
    }
};CDropTarget aDropTarget;//---------------------------------------------------------------------------
__fastcall TfrmDropmain::TfrmDropmain(TComponent* Owner)
    : TForm(Owner)
{
    HWND hw = FindWindowEx(GetDesktopWindow(), NULL, "Shell_TrayWnd", 0);
    hw = FindWindowEx(hw, NULL, "TrayNotifyWnd", 0);
    hw = FindWindowEx(hw, NULL, "SysPager", 0);
    //hw = FindWindowEx(hw, NULL, "ToolbarWindow32", 0);    HRESULT hr = RegisterDragDrop(hw, &aDropTarget);
    if (hr != S_OK)
    {
        AnsiString Info;
        Info.printf("RegisterDragDrop failed %x", hr);
        ShowMessage(Info);
    }
}
//---------------------------------------------------------------------------
 __fastcall TfrmDropmain::~TfrmDropmain()
{    HWND hw = FindWindowEx(GetDesktopWindow(), NULL, "Shell_TrayWnd", 0);
    hw = FindWindowEx(hw, NULL, "TrayNotifyWnd", 0);
    hw = FindWindowEx(hw, NULL, "SysPager", 0);
    //hw = FindWindowEx(hw, NULL, "ToolbarWindow32", 0);    RevokeDragDrop(hw);
}
void __fastcall TfrmDropmain::TrayIcon1Click(TObject *Sender)
{
        /*
         Application->ShowMainForm = true;
            ShowWindow(Application->Handle, SW_SHOW);
           this->Show();         Application->ShowMainForm = false;
         ShowWindow(Application->Handle, SW_HIDE);
         Application->MainForm->Visible = false;
         Application->Minimize();   
         HWND hw = FindWindow("TForm1","Form1");
    ShowWindow(hw,SW_SHOW);         */
         //HWND hw = FindWindowEx(GetDesktopWindow(), NULL, "Shell_TrayWnd", 0);
         //FrmMain
         //SendMessage
}
void __fastcall TfrmDropmain::WndProc(TMessage &Msg)
{    if(Msg.Msg == 0x0400+101)
    {         Close();
    }
   TForm::WndProc(Msg);
}
//---------------------------------------------------------------------------
C++Builder的代码

Answer 2

很想帮你，但你贴的代码，我尝试调试没有成功你可以直接把BCB的工程打包发给或者告诉下载连接
我先看看效果是什么