Problems with VariantChangeType and VT_BOOL in CE - C / C++ / MFC Discussion Boards

BuckBrown31-Jan-06 11:23

31-Jan-06 11:23

Hi,

I am using Visual C++ version 6.0. I created a dialog based application using the MFC app wizard. Using the resource editor I placed a Tab Control in the dialog box and used the class wizard to give a variable name to the control. I can run the application and create the tab control with the tab text of my coice on the five tabs that I have. It seems I can select each tab. Where I am falling short is how to put other controls into each pane. I can only access and look at the properties for IDD_TAB1. How do I access the other panes and how do I put controls into the panes? If I try to put a control into IDD_TAB1 it is simply put "behind" the tab control as part of the dialog box.

Thanks,

Buck

Re: Tab Controls

Stephen Hewitt31-Jan-06 11:47

Stephen Hewitt

31-Jan-06 11:47

This is where Windows .RC files let the team down - They don't support a hierarchy of windows so there is no direct way to place windows on (should I say in) the tab control. I create the tab contents programmatically and place it in the tab control. The contents is often a single control or perhaps a modeless dialog.

Steve

Re: Tab Controls

_anil_31-Jan-06 17:28

_anil_

31-Jan-06 17:28

you can place the control in a separate dialog box.
then put the dialog box as a whole on the tab pane.

Re: Tab Controls

Stephen Hewitt31-Jan-06 17:30

Stephen Hewitt

31-Jan-06 17:30

Didn't I say that? ("or perhaps a modeless dialog").

Steve

Re: Tab Controls

_anil_31-Jan-06 18:41

_anil_

31-Jan-06 18:41

Sorry for being misplaced the reply,
actually I should reply to the questions but by mistake I did it to you.

Sorry.

Re: Tab Controls

Stephen Hewitt31-Jan-06 18:44

Stephen Hewitt

31-Jan-06 18:44

Easily done.

Steve

Re: Tab Controls

Owner drawn31-Jan-06 17:29

Owner drawn

31-Jan-06 17:29

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/shellcc/platform/commctls/tab/tab.asp[^]

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Problems with VariantChangeType and VT_BOOL in CE

Paul M Watt31-Jan-06 10:55

Paul M Watt

31-Jan-06 10:55

Hi All,

I have discovered that when I convert a BSTR to both VT_I4 or VT_BOOL format
with VariantChangeType, a second thread appears in my application, and in
most cases simply sits in the background suspended. If I try to context
switch to that thread through the debugger and watch where it goes, my
connection to the debugger is lost and I must warmboot my device.

If I use VariantChangeType to convert from a long to a BSTR, this errent
thread does not appear.

One final note, when the program shuts down with this errent thread, an
exception is thrown, invalid access, probably because of that other thread.

Has anyone run into this, or is there any information on what is going on,
or how a developer is supposed to work around this?

Here is the code for this program to test this problem.

Thanks

-----------------------------------------------

#include <windows.h>

//C: Link in the library that contains the Variant functions.
#pragma comment(linker, "/defaultlib:oleaut32.lib")

int WINAPI WinMain( HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPTSTR lpCmdLine,
int nCmdShow)
{
//C: Initialize the variant object.
VARIANT v;
::VariantInit(&v);

//C: Test the different conversions independantly.
#ifdef BSTR_TEST
v.vt = VT_I4;
v.lVal = -1;

::VariantChangeType(&v, &v, 0, VT_BSTR);

BSTR bstr = v.bstrVal;
//C: No extra thread, PASSES.
#elif defined(LONG_TEST)
v.vt = VT_BSTR;
v.bstrVal = ::SysAllocString(L"-1");

::VariantChangeType(&v, &v, 0, VT_I4);

long l = v.lVal;
//C: At this point a second thread will have been created. FAILS
#else
v.vt = VT_BSTR;
v.bstrVal = ::SysAllocString(L"-1");

::VariantChangeType(&v, &v, 0, VT_BOOL);

VARIANT_BOOL b = v.boolVal;
//C: At this point a second thread will have been created. FAILS
#endif
//C: Free resources.
::VariantClear(&v);
return 0;
}

//C: If the second thread is created, when the program exits, an exception
is thrown.

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device manager refresh

Manu_8131-Jan-06 9:36

Manu_81

31-Jan-06 9:36

Hi,
I am trying to the device manager refresh in win32.
How to do that. Thanks.

Re: device manager refresh

Blake Miller31-Jan-06 10:29

Blake Miller

31-Jan-06 10:29

WM_DEVICECHANGE
The WM_DEVICECHANGE device message notifies an application of a change to the hardware configuration of a device or the computer.
A window receives this message through its WindowProc function.

HTH Cool | :cool:

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Re: device manager refresh

Manu_8131-Jan-06 11:45

Manu_81

31-Jan-06 11:45

But that's not I want. I am not plugging in any devices to watch for WM_DEVICECHANGE message. I just want to force a device manager refresh ( just as we do manually in the control panel-device manager-scan for hardware changes but programatically)

-- modified at 17:46 Tuesday 31st January, 2006

Re: device manager refresh

Ryan Binns31-Jan-06 17:28

Ryan Binns

31-Jan-06 17:28

Yeah, so send it a WM_DEVICECHANGE message - it will catch it and think something has changed, so will refresh.

Ryan

"Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

Trying to expand a tree...

KellyR31-Jan-06 9:06

KellyR

31-Jan-06 9:06

Hi!

Here's what I have:

HWND window = GetDlgItem(hDlg, IDC_TREE);

TVINSERTSTRUCT tvInsert;
tvInsert.item.mask = TVIF_TEXT;
tvInsert.item.pszText = _T("Parent");

HTREEITEM hTreeItem = (HTREEITEM)SendMessage(window,TVM_INSERTITEM,0,(LPARAM) (LPTVINSERTSTRUCT) &tvInsert);
SendMessage(window,TVM_INSERTITEM,0,(LPARAM) (LPTVINSERTSTRUCT) &tvInsert);

tvInsert.hParent = hTreeItem;
tvInsert.item.pszText = _T("Child");
SendMessage(window,TVM_INSERTITEM,0,(LPARAM) (LPTVINSERTSTRUCT) &tvInsert);

SendMessage(window,TVM_EXPAND, (WPARAM)(UINT)TVE_EXPAND,(LPARAM) (HTREEITEM) &hTreeItem);

BUuuuut.. the tree doesn't expand for some reason. I've tried collapsing it first then expanding, same thing, it just won't expand.

Kelly Ryan

Re: Trying to expand a tree...

Stephen Hewitt31-Jan-06 11:53

Stephen Hewitt

31-Jan-06 11:53

KellyR wrote:
SendMessage(window,TVM_EXPAND, (WPARAM)(UINT)TVE_EXPAND,(LPARAM) (HTREEITEM) &hTreeItem);

This line is wrong, it should read:
SendMessage(window, TVM_EXPAND, TVE_EXPAND, reinterpret_cast<LPARAM>(hTreeItem));

In particular you have a "&hTreeItem" where you should have just a "hTreeItem". I couldn't resist removing the old style C casts and replacing them with function style casts (which IMHO should be used in practically all new C++ code).

Steve

Re: Trying to expand a tree...

KellyR2-Feb-06 4:12

KellyR

2-Feb-06 4:12

Great, that worked, thanks a lot.

Kelly Ryan

Is there a specific size for a 2 dimentional array

Deema Jack31-Jan-06 8:18

Deema Jack

31-Jan-06 8:18

Is there a specific size for the elements in a 2 dimentional array .
I mean can I use an array with this matrix [100][5] or No .

Re: Is there a specific size for a 2 dimentional array

Dethulus31-Jan-06 8:31

Dethulus

31-Jan-06 8:31

If I understand your question correctly the answer is yes. All elements in any array are the same size. Accessing a 2 dimensional array as you described is simply a matter of indexing it properly. Assuming you've declared your array as:

int nArray[100][5];

You could assign x to any element in the array with any of the following methods:

<br />
int i, j, x;<br />
<br />
x = nArray[75][4];<br />
for(i=0; i<100; i++)<br />
{<br />
   for(j=0; j<5; j++)<br />
   {<br />
      x = nArray[i][j];<br />
      // ... do something with x;<br />
   }<br />
}<br />

However, unlike in BASIC you can't access element nArray[100][5]. Array access is always zero relative.

Hope this helps...

-Dethulus

Selecting an item by Keystrokes

Kurt _B31-Jan-06 8:11

Kurt _B

31-Jan-06 8:11

I have a list control and I want to add functionality to select an item by the key cobination entered similar to windows explorer & outlook. If anyone could point me in the right direction that would be great.

Re: Selecting an item by Keystrokes

Owner drawn31-Jan-06 22:47

Owner drawn

31-Jan-06 22:47

WM_CHARTOITEM

I know this is not the one you are looking for but still this could help you. This is for listbox.

BTW if you find the solution please mention it here.

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Re: Selecting an item by Keystrokes

Kurt _B1-Feb-06 2:15

Kurt _B

1-Feb-06 2:15

Not using listbox.

How to gray out a control

Robert Palma Jr.31-Jan-06 6:26

Robert Palma Jr.

31-Jan-06 6:26

I need to gray-out an Edit Box, Pushbutton and Check Box.
I know how to show and hide it with ShowWindow()

GetDlgItem(IDC_BUTT_testupload)->ShowWindow(SW_HIDE);

but how do I gray it out so that it is inactive but
still gray-visible to the User?

VC++ 6.0

Many thanks,
Robert Smile | :)