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i am new to directx.
i want to use directx to capture screen , could you give me some examples (visual c++) or suggestions about this?
any hints will be helpful
thx
includeh10
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I need to list the attributes of an autocad block reference :
_variant_t arrayAttrib; // array of AttributeRef objects
IAcadAttributeReferencePtr pAttribRef = NULL;
long lbound, ubound;
HRESULT result;
arrayAttrib = pAcadBlockRef->GetAttributes();
SafeArrayGetLBound(arrayAttrib.parray, 1, &lbound);
SafeArrayGetUBound(arrayAttrib.parray, 1, &ubound);
for (long i = lbound; i <= ubound; i++)
{
result = SafeArrayGetElement(arrayAttrib.parray, &i, pAttribRef);
...
}
GetAttributes() works : i get an array of attributes in a variant;
but SafeArrayGetElement return error code and pAttribRef is not initialized.
JPG
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And the HRESULT is....
Steve S
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IAcadAttributeReferencePtr pAttribRef = NULL;
...
result = SafeArrayGetElement(arrayAttrib.parray, &i, pAttribRef);
result = E_INVALIDARG : one of the arguments is invalid.
Of course the invalid argument must be pAttribRef, but i have no
idea of the way to persuade SafeArrayGetElement to put what i want
in this argument ...
I have already used SafeArrayGetElement to extract simple values
(int, char buffer, ...), but not a com object.
Perhaps my IAcadAttributeReferencePtr is 'hidden' in a variant ?
I try this :
_variant_t val;
result = SafeArrayGetElement(arrayAttrib.parray, &i, &val); // --> result = S_OK
but when looking inside this variant, I have no clue to extract what i want.
Autocad documentation gives only examples in VBA, where all seems so simple...
thank you for your help
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Ah. Try
result = SafeArrayGetElement(arrayAttrib.parray, &i, &pAttribRef);
instead, and see if you get the same error.
I guess you won't...
Steve S
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yes result is S_OK with your version, but ...
when i try to use the returned pAttribRef object :
if (result == S_OK)
strTag = pAttribRef->GetTagString();
i have an error msg box :
"The value of ESP was not properly saves across a function call.
This is usually a result of calling a function declared with one
calling convention with a function pointer declared with a different
calling convention."
so ..
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One step forwards, two steps back.
This is generally due to a mismatch of __cdecl and __stdcall. COM methods are generally (always?) __stdcall, I think. At this point, I'd probably put a breakpoint on the strTag = ... line and then step in using the assembly view, to make sure the interface/vtable in pAttribRef was really OK.
Where are your definitions of the AutoCAD stuff coming from? Presumably you've '#import'-ed a typelib or DLL?
Steve S
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once again tank you for your commitment, i must say i'm completely
lost at this point, but you seems to know what you're talking about ...
where do come from the autocad stuff :
in the class wizard of visual studio, i did 'import class from a type library'
and then choosed acad.tlb in the autocad directory. The class wizard generated then
the file acad.tlh (see attached file). This file contains definitions of all the functions
exposed by autocad.
the autocad program is started this way :
HRESULT hr;
// chercher un Acad en train de tourner
hr = m_acadApp.GetActiveObject("AutoCAD.Application.15");
if( FAILED(hr) )
{
TESTHR( hr= m_acadApp.CreateInstance( "AutoCAD.Application.15", NULL, CLSCTX_LOCAL_SERVER ));
if(hr == REGDB_E_CLASSNOTREG)
{
AfxMessageBox("AutoCAD is not registered on this machine");
goto End;
}
if(m_acadApp == NULL)
{
Erreur = 1;
goto End;
}
...
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EH OH Steve,
did i say something very bad to you ?(in that case sorry, english is not my
first langage).
Or my previous mail was so stupid, you don't want to bother anymore ?
Or I was asking too much when i asked you to look inside the .tlh file ?
Or simply you don't see an explanation to my problem ?
I'm hanging ...
JPG
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OK I have the answer to my previous post : it was option 2 (so stupid).
When receiving the mails from Codeproject in Outlook, i see 'Steve S' as the sender.
So I innocently sent my reply (with the attached file) back to the sender; it's
only now that I realize the sender was 'forums@codeproject.com' ... (i must say for my defense it's the first time i made a post on CodeProject).
Anyway... Steve, if you're still on the subject, here are the occurences of
GetAttributes that i find in acad.tlh :
struct __declspec(uuid("2928d4a2-ca93-11d1-b60f-0060b087e235"))
IAcadBlockReference : IAcadEntity
{
...
// Wrapper methods for error-handling
...
_variant_t GetAttributes ( );
...
// Raw methods provided by interface
...
virtual HRESULT __stdcall raw_GetAttributes (VARIANT * pAttrObjs ) = 0;
...
}
// Function implementation mapping
#pragma start_map_region("d:\polar32JPG\spacad\debug\acad.tli")
{
// Wrapper methods for error-handling
...
__declspec(implementation_key(1096)) _variant_t IAcadBlockReference::GetAttributes ( );
...
}
JPG
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and, persevering in my 'monologue' (chat with myself),
here are the occurences of IAcadBlockReference (the object i'm trying to get of the array returned by GetAttributes() ) :
namespace AutoCAD {
...
struct __declspec(uuid("2928d4a2-ca93-11d1-b60f-0060b087e235"))
/* dual interface */ IAcadBlockReference;
...
}
// Smart pointer typedef declarations
_COM_SMARTPTR_TYPEDEF(IAcadBlockReference, __uuidof(IAcadBlockReference));
struct __declspec(uuid("2928d4a2-ca93-11d1-b60f-0060b087e235"))
IAcadBlockReference : IAcadEntity
{
...
...
}
struct __declspec(uuid("2928d4a3-ca93-11d1-b60f-0060b087e235"))
AcadBlockReference;
// [ default ] interface IAcadBlockReference
// [ default, source ] interface IAcadObjectEvents
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(Fx: Wakes up, staring at screen thinking - I must try and work fewer hours this week...)
Your GetAttributes is returning a _variant_t. This is probably a safearray, so you need to check the vt member to determine the type.
if (vt == (VT_ARRAY|VT_UNKNOWN)) || vt == (VT_ARRAY|VT_DISPATCH))
This would mean it's a SAFEARRAY of either IUnknown or IDispatch values.
It's not clear from the context what the bounds of the array are, but there are functions to tell you (see SafeArrayGetDim), but chances are it's single dimension, so you can use SafeArrayGetUBound(1) and SafeArrayGetLBound(1) to find the max and min elements in it.
Then you should be able to use SafeArrayGetElement to get a copy of the interface. Don't forget that you pass the address of an index variable to SafeArrayGetElement, not the index itself.
If you want to iterate over the attributes, then SafeArrayAccessData and SafeArrayUnaccessData around a loop will be more efficient, but that deals with a pointer to the data, and you're responsible for doing your own copying.
The call can't directly return the interface you would expect, unless it's IUnknown or IDispatch, in which case it's either the punkVal (IUnknown) or pdispVal (IDispatch). Since they both support QueryInterface, it's no problem to use either of them the get the interface you actually want, but you absolutely must do that, rather than a simple assignment/cast.
It's probable that the pointer isn't pointing to an appropriate v-table anyway.
It's possible that GetAttributes() might return VT_ARRAY|VT_VARIANT, in which case you then have an extra step involved in examining the variant you get back.
Hope this helps
(and no, I wasn't offended by your email - sometimes work just gets in the way of things, like those stupid people who write viruses and worms...)
Steve S
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In fact i have no problem with GetAttributes : i know it returns a valid safearray
(variant type = VT_ARRAY|VT_DISPATCH); SafeArrayGetLBound & SafeArrayGetUBound return
correct values.
The problem is extracting a IAcadAttributeReference * from that array :
if i try to extract a variant from the array (presuming that the IAcadAttributeReference * is a member of the variant) :
_variant_t val; // i tried also with _variant_t *val
result = SafeArrayGetElement(arrayAttrib.parray, &i, &val); // result = S_OK
switch(val.vt)
{
case VT_BYREF|VT_UNKNOWN: ...
break;
case VT_BYREF|VT_DISPATCH: ...
break;
case VT_UNKNOWN: ...
break;
case VT_DISPATCH: ...
break;
case VT_ARRAY: ...
break;
}
val.vt does not correspond to any case of the switch
and most members of val are clearly invalid (0xccccccc)
-------------------
i understand you have others things to do than finding solutions to other people
problems; what you have already done is very kind, so if you don't see an evident
solution, don't mind. Thanks.
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Ah hah!
You're trying to retrieve into a variant. What you should do is retrieve into an IDispatch, because that's what's in the array.
CComPtr<idispatch> myDisp;
result = SafeArrayGetElement(arrayAttrib.parray, &i, &myDisp);
// Should give S_OK
CComQIPtr<iacadattributereference, &iid_iacadattributereference=""> myAttrib;
try
{
myAttrib = myDisp;
}
catch(_com_error& e)
{
result = E_NOINTERFACE;
}
catch(...)
{
result = E_FAIL;
}
if (result==S_OK)
{
// do your thing here...
}
Since the CComPtr and CComQIPtr are smart, they'll release when they go out of scope. SafeArrayGetElement will give you a copy of the element, and in this context means it will be a reference counted interface which you must release, CComPtr will do that bit for you.
You might need to modify your #import to generate the named guids for interfaces etc.
Hope this helps.
[Sorry if I seemed grouchy, I'm having a bad day...]
Steve S
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Curse that HTML!
It should, of course, read...
CComPtr <myDisp>;
result = SafeArrayGetElement(arrayAttrib.parray, &i, &myDisp);
// Should give S_OK
CComQIPtr <myAttrib,&IID_AcadAttributeReference>;
try
{
myAttrib = myDisp;
}
catch(_com_error& e)
{
result = E_NOINTERFACE;
}
catch(...)
{
result = E_FAIL;
}
if (result==S_OK)
{
// do your thing here...
}
Steve S
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there is progress, but ...
CComPtr<iacadattributereference> myDisp;
CComQIPtr<iacadattributereference ,&__uuidof(iacadattributereference)=""> myAttrib;
result = SafeArrayGetElement(arrayAttrib.parray, &i, &myDisp); // --> S_OK
try
{
myAttrib = myDisp;
if (result == S_OK)
myAttrib->GetColor(); //--> "access violation" in oleaut32.dll
...
What is strange is that, when looking inside myAttrib, it has type IAcadEntity,
and not IAcadAttributeReference; IAcadAttributeReference is derived from IAcadEntity.
GetColor() is a method of IAcadAttributeReference, and it did "access violation" in oleaut32.dll (the catch(_com_error& e) didn't catch anything).
If I try myAttrib->GetHeight(), where GetHeight() is a method of IAcadEntity, the
message is
"The value of ESP was not properly saved across a function call.
This is usually a result of calling a function declared with one
calling convention with a function pointer declared with a different
calling convention."
I don't know if it can give you some light : GetHeight() is :
inline double AutoCAD::IAcadAttributeReference::GetHeight ( )
{
double _result;
HRESULT _hr = get_Height(&_result);
if (FAILED(_hr)) _com_issue_errorex(_hr, this, __uuidof(this));
return _result;
}
and
struct __declspec(uuid("2928d4a0-ca93-11d1-b60f-0060b087e235"))
IAcadAttributeReference : IAcadEntity
{
...
virtual HRESULT __stdcall get_Height (double * Height ) = 0;
}
-------
My boss, who is a lot more aware of COM than me (but that's easy), has no clue.
So it's up to you, you grouchy 
JPG
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Just wait...
I'm beginning to understand.
When you write myDisp, you mean an object of type IDispatch.
So in my case i declare CComPtr<IAcadObject> myDisp;
When you write myAttrib, you mean an object of type IAcadAttributeReference.
So i declare CComQIPtr<IAcadAttributeReference ,&__uuidof(IAcadAttributeReference)> myAttrib;
I will try that immediately ...
(my previous post was also corrupted by the remove of <> !)
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IT WORKED !!!
long i = 0;
CComPtr<IAcadObject> myDispatch;
CComQIPtr<IAcadAttributeReference ,&__uuidof(IAcadAttributeReference)> myAttrib;
try
{
result = SafeArrayGetElement(arrayAttrib.parray, &i, &myDispatch);
myAttrib = myDispatch;
if (result == S_OK)
{
double dist = myAttrib->GetHeight();
Wonderful support, thanks you very much, and now let's get some work done please
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I have impelemented the following code:
STDMETHODIMP CCSerialno::MachineID()
{
// TODO: Add your implementation code here
char bufVolumeLabel[255] ="";
DWORD Size=255;
DWORD SerialNo;
long Slnum=0;
DWORD MCL;
DWORD Flags;
char bufFileSystem[255] ="";
for (int iCounter=0;iCounter
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In your C++ code,
<br />
STDMETHODIMP CCSerialno::MachineID(long *machineID)<br />
{<br />
...<br />
*machineID = ...;<br />
...<br />
}<br />
In your IDL interface,
HRESULT MachineID([out,retval]long *machineID);
RSS feed
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What the method returns is an HRESULT, which simply reveals success or failure.
Your IDL (or ODL) for the method needs to be
HRESULT MachineID([out,retval]long *pSerialNo)
and you need to modify the C++ declaration and code
STDMETHODIMP CCSerialno::MachineID(long* pRes)
{
// TODO: Add your implementation code here
TCHAR bufVolumeLabel[255] = _T("");
DWORD Size=255;
DWORD SerialNo;
long Slnum=0;
DWORD MCL;
DWORD Flags;
TCHAR bufFileSystem[255] =_T("");
for (int iCounter=0;iCounter < 26; i++)
{
if (GetDriveType((LPCTSTR)(HardDiskLetters[iCounter]))==DRIVE_FIXED)
if (GetVolumeInformation((LPCTSTR)(HardDiskLetters[iCounter]),
(LPTSTR)(bufVolumeLabel),Size,&SerialNo,&MCL,&Flags,(LPTSTR)(bufFileSystem),Size))
{
Slnum=Slnum+SerialNo;
}
}
if (pRes!=NULL)
{
*pRes = Slnum;
return S_OK;
}
return E_INVALIDARG;
}
Steve S
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We aim to please!
Steve S
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I am trying to implement tree control context menus and their not working very well. When right-clicking on an item, the item is not selected, making the context menu very useless. The tree control is in a dialog bar. What could be the problem?
-- Steve
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