查了MSDN，發(fā)現(xiàn)Windows支持Drag and Drop的方法是四個(gè)COM：IEnumFORMATETC、IDataObject、IDropSource和IDropTarget。為了讓自己做的一個(gè)代碼編輯文本框里面的代碼可以被拖出去拖進(jìn)來(lái)，無(wú)奈之下只好實(shí)現(xiàn)了這四個(gè)東西。
實(shí)現(xiàn)了之后，程序剛開始需要調(diào)用OldInitialize(NULL);，結(jié)束的時(shí)候調(diào)用OnUninitialize();，控件創(chuàng)建的時(shí)候調(diào)用RegisterDragDrop，控件結(jié)束的時(shí)候調(diào)用RevokeDragDrop。然后就可以通過(guò)這些COM來(lái)做Drag and Drop了。下面是接口的實(shí)現(xiàn)：
頭文件：
1 /*******************************************************************************
2 Vczh Library++ 2.0
3 Vczh Coder::文本拖曳
4 開發(fā)者：陳梓瀚
5
6 接口：
7 類：
8 TextProvider ：文本拖曳處理器
9 函數(shù)：
10 *******************************************************************************/
11 #ifndef VCZHCODER_TEXTPROVIDER
12 #define VCZHCODER_TEXTPROVIDER
13
14 #include <objidl.h>
15 #include "..\..\..\..\VL++\Library\Data\Data\VL_Data_String.h"
16
17 using namespace vl;
18
19 class TextProvider : public IEnumFORMATETC , public IDataObject , public IDropSource , public IDropTarget
20 {
21 protected:
22 VBool FEnumeratorReaded;
23 FORMATETC FAvailableFormat;
24 HGLOBAL FGlobal;
25
26 virtual VBool OnDragDropGetData(VUnicodeString& String)=0;
27 virtual void OnDragOver(VInt X , VInt Y)=0;
28 virtual void OnDragEnter()=0;
29 virtual void OnDragLeave()=0;
30 virtual void OnDrop(VUnicodeString String , VInt X , VInt Y)=0;
31 public:
32 TextProvider();
33 ~TextProvider();
34
35 VBool Drag();
36
37 HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid , __RPC__deref_out void __RPC_FAR *__RPC_FAR *ppvObject);
38 ULONG STDMETHODCALLTYPE AddRef();
39 ULONG STDMETHODCALLTYPE Release();
40
41 HRESULT STDMETHODCALLTYPE Next(ULONG celt , FORMATETC *rgelt , ULONG *pceltFetched);
42 HRESULT STDMETHODCALLTYPE Skip(ULONG celt);
43 HRESULT STDMETHODCALLTYPE Reset();
44 HRESULT STDMETHODCALLTYPE Clone(__RPC__deref_out_opt IEnumFORMATETC **ppenum);
45
46 HRESULT STDMETHODCALLTYPE GetData(FORMATETC *pformatetcIn ,STGMEDIUM *pmedium);
47 HRESULT STDMETHODCALLTYPE GetDataHere(FORMATETC *pformatetc , STGMEDIUM *pmedium);
48 HRESULT STDMETHODCALLTYPE QueryGetData(__RPC__in_opt FORMATETC *pformatetc);
49 HRESULT STDMETHODCALLTYPE GetCanonicalFormatEtc(__RPC__in_opt FORMATETC *pformatectIn , __RPC__out FORMATETC *pformatetcOut);
50 HRESULT STDMETHODCALLTYPE SetData(FORMATETC *pformatetc , STGMEDIUM *pmedium , BOOL fRelease);
51 HRESULT STDMETHODCALLTYPE EnumFormatEtc(DWORD dwDirection , __RPC__deref_out_opt IEnumFORMATETC **ppenumFormatEtc);
52 HRESULT STDMETHODCALLTYPE DAdvise(__RPC__in FORMATETC *pformatetc , DWORD advf , __RPC__in_opt IAdviseSink *pAdvSink , __RPC__out DWORD *pdwConnection);
53 HRESULT STDMETHODCALLTYPE DUnadvise(DWORD dwConnection);
54 HRESULT STDMETHODCALLTYPE EnumDAdvise(__RPC__deref_out_opt IEnumSTATDATA **ppenumAdvise);
55
56 HRESULT STDMETHODCALLTYPE QueryContinueDrag(BOOL fEscapePressed , DWORD grfKeyState);
57 HRESULT STDMETHODCALLTYPE GiveFeedback(DWORD dwEffect);
58
59 HRESULT STDMETHODCALLTYPE DragEnter(__RPC__in_opt IDataObject *pDataObj , DWORD grfKeyState , POINTL pt , __RPC__inout DWORD *pdwEffect);
60 HRESULT STDMETHODCALLTYPE DragOver(DWORD grfKeyState , POINTL pt , __RPC__inout DWORD *pdwEffect);
61 HRESULT STDMETHODCALLTYPE DragLeave();
62 HRESULT STDMETHODCALLTYPE Drop(__RPC__in_opt IDataObject *pDataObj , DWORD grfKeyState , POINTL pt , __RPC__inout DWORD *pdwEffect);
63 };
64
65 #endif
代碼文件：
1 #include <windows.h>
2 #include "TextProvider.h"
3 #include "..\..\..\..\VL++\Library\Windows\VL_WinMain.h"
4
5 using namespace vl::windows;
6
7 TextProvider::TextProvider()
8 {
9 FEnumeratorReaded=false;
10 FAvailableFormat.cfFormat=CF_TEXT;
11 FAvailableFormat.ptd=0;
12 FAvailableFormat.dwAspect=DVASPECT_ICON;
13 FAvailableFormat.lindex=-1;
14 FAvailableFormat.tymed=TYMED_HGLOBAL;
15 FGlobal=0;
16 }
17
18 TextProvider::~TextProvider()
19 {
20 }
21
22 VBool TextProvider::Drag()
23 {
24 VUnicodeString String;
25 if(!OnDragDropGetData(String))
26 {
27 return false;
28 }
29
30 FGlobal=GlobalAlloc(GMEM_FIXED,(String.Length()+1)*sizeof(VWChar));
31 VMbcsString Mbcs=ToMbcs(String);
32 memcpy((VPointer)FGlobal,Mbcs.Buffer(),Mbcs.Length()+1);
33
34 DWORD Effect=DROPEFFECT_MOVE|DROPEFFECT_COPY;
35 DWORD Result=0;
36 if(DoDragDrop(this,this,Effect,&Result)==DRAGDROP_S_DROP)
37 {
38 switch(Result)
39 {
40 case DROPEFFECT_MOVE:
41 return true;
42 case DROPEFFECT_COPY:
43 return false;
44 default:
45 if(FGlobal)
46 {
47 GlobalFree(FGlobal);
48 FGlobal=0;
49 }
50 return false;
51 }
52 }
53 else
54 {
55 if(FGlobal)
56 {
57 GlobalFree(FGlobal);
58 FGlobal=0;
59 }
60 return false;
61 }
62 }
63
64 HRESULT STDMETHODCALLTYPE TextProvider::QueryInterface(REFIID riid , __RPC__deref_out void __RPC_FAR *__RPC_FAR *ppvObject)
65 {
66 if(riid==IID_IUnknown)
67 {
68 *ppvObject=static_cast<IUnknown*>(static_cast<IDataObject*>(this));
69 }
70 else if(riid==IID_IEnumFORMATETC)
71 {
72 IEnumFORMATETC* Object=this;
73 *ppvObject=Object;
74 }
75 else if(riid==IID_IDataObject)
76 {
77 IDataObject* Object=this;
78 *ppvObject=Object;
79 }
80 else if(riid==IID_IDropSource)
81 {
82 IDropSource* Object=this;
83 *ppvObject=Object;
84 }
85 else if(riid==IID_IDropTarget)
86 {
87 IDropTarget* Object=this;
88 *ppvObject=Object;
89 }
90 else
91 {
92 *ppvObject=NULL;
93 return E_NOINTERFACE;
94 }
95 return S_OK;
96 }
97
98 ULONG STDMETHODCALLTYPE TextProvider::AddRef()
99 {
100 return 1;
101 }
102
103 ULONG STDMETHODCALLTYPE TextProvider::Release()
104 {
105 return 1;
106 }
107
108 HRESULT STDMETHODCALLTYPE TextProvider::Next(ULONG celt , FORMATETC *rgelt , ULONG *pceltFetched)
109 {
110 if(FEnumeratorReaded)
111 {
112 if(pceltFetched)
113 {
114 *pceltFetched=0;
115 }
116 return S_FALSE;
117 }
118 else
119 {
120 FEnumeratorReaded=true;
121 if(celt)
122 {
123 if(pceltFetched)
124 {
125 *pceltFetched=1;
126 }
127 if(rgelt)
128 {
129 *rgelt=FAvailableFormat;
130 }
131 }
132 return celt==1?S_OK:S_FALSE;
133 }
134 }
135
136 HRESULT STDMETHODCALLTYPE TextProvider::Skip(ULONG celt)
137 {
138 return S_FALSE;
139 }
140
141 HRESULT STDMETHODCALLTYPE TextProvider::Reset()
142 {
143 FEnumeratorReaded=false;
144 return S_OK;
145 }
146
147 HRESULT STDMETHODCALLTYPE TextProvider::Clone(__RPC__deref_out_opt IEnumFORMATETC **ppenum)
148 {
149 *ppenum=static_cast<IEnumFORMATETC*>(this);
150 return S_OK;
151 }
152
153 HRESULT STDMETHODCALLTYPE TextProvider::GetData(FORMATETC *pformatetcIn ,STGMEDIUM *pmedium)
154 {
155 if(pformatetcIn->cfFormat!=CF_TEXT || pformatetcIn->tymed!=TYMED_HGLOBAL)
156 {
157 return DV_E_FORMATETC;
158 }
159 pmedium->tymed=TYMED_HGLOBAL;
160 pmedium->hGlobal=FGlobal;
161 pmedium->pUnkForRelease=NULL;
162 FGlobal=0;
163 return S_OK;
164 }
165
166 HRESULT STDMETHODCALLTYPE TextProvider::GetDataHere(FORMATETC *pformatetc , STGMEDIUM *pmedium)
167 {
168 return DV_E_TYMED;
169 }
170
171 HRESULT STDMETHODCALLTYPE TextProvider::QueryGetData(__RPC__in_opt FORMATETC *pformatetc)
172 {
173 if(pformatetc->cfFormat!=CF_TEXT || pformatetc->tymed!=TYMED_HGLOBAL)
174 {
175 return DV_E_FORMATETC;
176 }
177 else
178 {
179 return S_OK;
180 }
181 }
182
183 HRESULT STDMETHODCALLTYPE TextProvider::GetCanonicalFormatEtc(__RPC__in_opt FORMATETC *pformatectIn , __RPC__out FORMATETC *pformatetcOut)
184 {
185 *pformatetcOut=FAvailableFormat;
186 return DATA_S_SAMEFORMATETC;
187 }
188
189 HRESULT STDMETHODCALLTYPE TextProvider::SetData(FORMATETC *pformatetc , STGMEDIUM *pmedium , BOOL fRelease)
190 {
191 return E_NOTIMPL;
192 }
193
194 HRESULT STDMETHODCALLTYPE TextProvider::EnumFormatEtc(DWORD dwDirection , __RPC__deref_out_opt IEnumFORMATETC **ppenumFormatEtc)
195 {
196 Reset();
197 *ppenumFormatEtc=static_cast<IEnumFORMATETC*>(this);
198 return S_OK;
199 }
200
201 HRESULT STDMETHODCALLTYPE TextProvider::DAdvise(__RPC__in FORMATETC *pformatetc , DWORD advf , __RPC__in_opt IAdviseSink *pAdvSink , __RPC__out DWORD *pdwConnection)
202 {
203 return OLE_E_ADVISENOTSUPPORTED;
204 }
205
206 HRESULT STDMETHODCALLTYPE TextProvider::DUnadvise(DWORD dwConnection)
207 {
208 return OLE_E_ADVISENOTSUPPORTED;
209 }
210
211 HRESULT STDMETHODCALLTYPE TextProvider::EnumDAdvise(__RPC__deref_out_opt IEnumSTATDATA **ppenumAdvise)
212 {
213 return OLE_E_ADVISENOTSUPPORTED;
214 }
215
216 HRESULT STDMETHODCALLTYPE TextProvider::QueryContinueDrag(BOOL fEscapePressed , DWORD grfKeyState)
217 {
218 if(fEscapePressed==TRUE)
219 {
220 return DRAGDROP_S_CANCEL;
221 }
222 else if(grfKeyState&MK_LBUTTON)
223 {
224 return S_OK;
225 }
226 else
227 {
228 return DRAGDROP_S_DROP;
229 }
230 }
231
232 HRESULT STDMETHODCALLTYPE TextProvider::GiveFeedback(DWORD dwEffect)
233 {
234 return DRAGDROP_S_USEDEFAULTCURSORS;
235 }
236
237 HRESULT STDMETHODCALLTYPE TextProvider::DragEnter(__RPC__in_opt IDataObject *pDataObj , DWORD grfKeyState , POINTL pt , __RPC__inout DWORD *pdwEffect)
238 {
239 IEnumFORMATETC* Enumerator=0;
240 VBool Found=false;
241 if(pDataObj->EnumFormatEtc(DATADIR_GET,&Enumerator)!=S_OK)return E_UNEXPECTED;
242 FORMATETC Format;
243 ULONG Fetched=0;
244 while(true)
245 {
246 Enumerator->Next(1,&Format,&Fetched);
247 if(Fetched==0)
248 {
249 break;
250 }
251 if(Format.cfFormat==CF_TEXT && Format.tymed==TYMED_HGLOBAL)
252 {
253 if(pDataObj->QueryGetData(&Format)==S_OK)
254 {
255 Found=true;
256 }
257 }
258 }
259 Enumerator->Release();
260 if(Found)
261 {
262 *pdwEffect=grfKeyState&MK_CONTROL?DROPEFFECT_COPY:DROPEFFECT_MOVE;
263 OnDragEnter();
264 }
265 else
266 {
267 *pdwEffect=DROPEFFECT_NONE;
268 }
269 return S_OK;
270 }
271
272 HRESULT STDMETHODCALLTYPE TextProvider::DragOver(DWORD grfKeyState , POINTL pt , __RPC__inout DWORD *pdwEffect)
273 {
274 if(*pdwEffect&DROPEFFECT_COPY || *pdwEffect&DROPEFFECT_MOVE)
275 {
276 *pdwEffect=grfKeyState&MK_CONTROL?DROPEFFECT_COPY:DROPEFFECT_MOVE;
277 OnDragOver(pt.x,pt.y);
278 }
279 else
280 {
281 *pdwEffect=DROPEFFECT_NONE;
282 }
283 return S_OK;
284 }
285
286 HRESULT STDMETHODCALLTYPE TextProvider::DragLeave()
287 {
288 OnDragLeave();
289 return S_OK;
290 }
291
292 HRESULT STDMETHODCALLTYPE TextProvider::Drop(__RPC__in_opt IDataObject *pDataObj , DWORD grfKeyState , POINTL pt , __RPC__inout DWORD *pdwEffect)
293 {
294 STGMEDIUM Medium;
295 if(!pDataObj->GetData(&FAvailableFormat,&Medium)==S_OK)
296 {
297 ShowMessage(GetApplication()->GetMainForm(),L"拖放源不支持將數(shù)據(jù)轉(zhuǎn)換成字符串，拖放失敗。",GetApplication()->GetMainForm()->GetText());
298 return E_UNEXPECTED;
299 }
300 if(Medium.tymed!=TYMED_HGLOBAL)
301 {
302 ReleaseStgMedium(&Medium);
303 ShowMessage(GetApplication()->GetMainForm(),L"拖放源不支持將數(shù)據(jù)使用HGLOBAL傳送，拖放失敗。",GetApplication()->GetMainForm()->GetText());
304 return E_UNEXPECTED;
305 }
306 PCChar Buffer=(PCChar)GlobalLock(Medium.hGlobal);
307 VUnicodeString String=ToUnicode(Buffer);
308 GlobalUnlock(Medium.hGlobal);
309 ReleaseStgMedium(&Medium);
310 OnDrop(String,pt.x,pt.y);
311 *pdwEffect=grfKeyState&MK_CONTROL?DROPEFFECT_COPY:DROPEFFECT_MOVE;
312 return S_OK;
313 }
寫了一整天。
posted on 2009-05-29 21:17
陳梓瀚(vczh) 閱讀(3064)
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