Im trying to read the value of a TextEdit box in a windows dialog and display the results using a MessageBox, however the results being displayed is just “Error”, when I run the program, even though there are no exceptions or error message in the debug section in visual studio. What am i doing wrong? Here is the subject code:
LPWSTR path;
GetDlgItemText(hDlg, IDC_PROGRAM, path, sizeof(path));
MessageBox(hDlg, NULL, path, MB_OK);
You are passing an uninitialized pointer and an incorrect buffer size to GetDlgItemText().
You need to allocate memory for a buffer for GetDlgItemText() to write into, and specify the max size of that buffer, eg:
WHAR path[MAX_PATH] = {};
GetDlgItemText(hDlg, IDC_PROGRAM, path, MAX_PATH);
MessageBox(hDlg, NULL, path, MB_OK);
Related
I'm trying to change the cursor of my mouse with a .cur file in a resource file.
When I'm try my code, I get this error:
Exception raised at 0x77EB7392 (ntdll.dll) in CleanResourceFiles.exe: 0xC0000005: Access Violation while reading location 0x00000066.
Here is the code:
HCURSOR curs = (HCURSOR)LoadImage(NULL, MAKEINTRESOURCE(IDC_CURSOR1), 2, 0, 0, LR_LOADFROMFILE);
SetSystemCursor(curs, 32512);
Note : IDC_CURSOR1 is my cursor and 32512 is the ID of the classic arrow cursor. I also included <Windows.h> and my resource.h.
I'm using Visual Studio Community 2017, with Win10.
I tried other functions, like LoadCursor(). The code above is from "VineMemz".
Finally, when I tried to change my cursor with LoadFromFile() using the path to my .cur file, it works.
When calling LoadImage(), you are specifying the LR_LOADFROMFILE flag, so the lpszName parameter will be interpreted as a pointer to a null-terminated string containing the path to the .cur file to load. But, you are passing in a resource ID number instead of a file path string (I'm assuming IDC_CURSOR1 is 102 (0x66), which would be consistent with the memory address reported in the error message). You need to get rid of the LR_LOADFROMFILE flag when loading an image from resources.
Also, you need to pass in the EXE's actual module handle in the hinst parameter, not NULL (NULL can only be used with loading OEM-defined images).
Also. you should not be using "magic numbers". The 2 on LoadImage() should be replaced with the IMAGE_CURSOR constant, and the 32512 on SetSystemCursor() should be replaced with the OCR_NORMAL constant.
Try this:
HCURSOR curs = (HCURSOR) LoadImage(GetModuleHandle(), MAKEINTRESOURCE(IDC_CURSOR1), IMAGE_CURSOR, 0, 0, 0);
SetSystemCursor(curs, OCR_NORMAL);
I'm writing a programme that should return the Value of a registry subkey. I tried this code:
LPCTSTR sk = TEXT("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run\\");
HKEY regkey;
char out[255];
RegOpenKeyEx(HKEY_CURRENT_USER, sk, 0, KEY_SET_VALUE, ®key);
RegGetValue(regkey, L"test", NULL, RRF_RT_ANY, NULL, (PVOID)&out, (LPDWORD) strlen(out) +1);
RegCloseKey(regkey);
MessageBox(NULL, (LP) out, L"Output", MB_OK);
I wrote this in Visual Studio 2017 and it doesn't show any errors. But when I run it, it crashes on line 5.
Crash reason:
Exception Error on 0x7511C481 (KernelBase.dll) in reader.exe: 0xC0000005: Access Violation While Reading at Location 0x00000005. (Translated by Google Translate)
I have already checked if RegOpenKeyEx() works and yes it does work.
What am I doing wrong and how to fix it?
You should use sizeof(out) and not strlen(out)+1. That variable is uninitizlied and depending on how you build this can either be filled with zeros (in which case you're telling RegGetValue() it can write 1 bytes into it) or it can have random data (in which case you're telling RegGetValue() it can write a random number of bytes).
The second issue is that RegOpenKeyEx() is called with KEY_SET_VALUE so you don't even have permission to read. You need KEY_QUERY_VALUE.
The third issue, and the one probably causing the crash, is that you cast the result of strlen(out)+1 to a pointer. It's a number, not a pointer. The function is expecting a pointer so it can write the number of bytes it actually read. Use:
DWORD len = sizeof(out);
RegGetValue(regkey, L"test", NULL, RRF_RT_ANY, NULL, (PVOID)&out, &len);
And finally, as all the comments mention, you should check for errors on all functions and handle all of them.
I'm on windows 8.1, visual studio 2017.
I'm using this pricedown font in a directx project I'm working on.
I load it with AddFontResourceEx and create a font for it with D3DXCreateFont.
When I hit "Local Windows Debugger" everything is fine, font renders. Be it in release or in debug mode.
Problem arises when I go through any executable, it never renders said font, be it release or debug.
So I went reading, I read the articles on msdn, this one and others whenever needed.
I don't think I'm doing anything wrong, my Resource View looks like this:
, and IDR_FONT1 looks like this:
The file is automatically loaded into the solution explorer (I didn't add it, VS did from the Resource.rc file), as you can see here:
With these proprieties:
I add it like so:
AddFontResourceEx("pricedown.ttf", FR_PRIVATE, 0);
this->createFont("Pricedown", 60, true, false);
Where createfont is my function to add the font (stripped down, it has arrays):
bool D3D9Render::createFont(char *name, int size, bool bold, bool italic)
{
D3DXCreateFont(m_pD3dDev, size, 0, (bold) ? FW_BOLD : FW_NORMAL, 0, (italic) ? 1 : 0, DEFAULT_CHARSET, OUT_DEFAULT_PRECIS, ANTIALIASED_QUALITY, DEFAULT_PITCH, name, &m_pFont);
return true;
}
I'm compiling it as x64 release.
As I've said, it works and renders the font when I press "Local Windows Debugger" (in any mode including x64 release), but when I go to project/x64/Release, it just won't render the font. Even the executable size is adequate.
GetLastError on the AddFontResource is 2 (ERROR_FILE_NOT_FOUND)
What am I doing wrong?
(Read the answer until the end, or you'll waste a lot of time.)
I got it. I had read over this blog post.
Here is an example on how to use AddFontMemResourceEx on a font file embedded in the resource.
HINSTANCE hResInstance = AfxGetResourceHandle( ); //Read the edit
HRSRC res = FindResource(
hResInstance,
MAKEINTRESOURCE(IDR_MYFONT),
L"BINARY" //Read The Edit
);
if (res)
{
HGLOBAL mem = LoadResource(hResInstance, res);
void *data = LockResource(mem);
size_t len = SizeofResource(hResInstance, res);
DWORD nFonts;
m_fonthandle = AddFontMemResourceEx(
data, // font resource
len, // number of bytes in font resource
NULL, // Reserved. Must be 0.
&nFonts // number of fonts installed
);
if(m_fonthandle==0)
{
MessageBox(L"Font add fails", L"Error");
}
}
Though you need afxwin.h, and from here:
afxwin.h is MFC and MFC is not included in the free version of VC++
(Express Edition)
EDIT:
You do not need to use AfxGetResourceHandle (why you would need afxwin.h), you can simply do:
HINSTANCE hResInstance = (HINSTANCE)GetModuleHandle(NULL);
And in FindResource, the 3rd parameter should be RT_FONT, and so you'd get:
HRSRC res = FindResource(hResInstance, MAKEINTRESOURCE(IDR_FONT1), RT_FONT);
I'm trying to get the current active window name with the code below :
HWND winHandle = GetActiveWindow();
wchar_t buffer[512] = L"";
int getT = GetWindowText(winHandle, (LPTSTR) buffer, 511);
When used on the window of the program, I get the window name correctly, otherwise, I'm getting error 1400. What could be the problem ?
Thanks
Error 1400 is ERROR_INVALID_WINDOW_HANDLE according to Microsoft's documentation. This means an invalid HWND is being passed to GetWindowText.
Working backwards, this means GetActiveWindow didn't return a valid handle, probably NULL instead. According to a comment on the documentation for GetActiveWindow this will happen when the active window doesn't belong to the current application or thread.
I am facing a problem on the WriteFile(); function using Win32 C++ Application. the second argument asks for a pointer to the buffer that is storing the information. what Syntax do I use to point the input text from the boxes? My information is text from the input of text boxes. What syntax do i use to create a pointer to that?
Here is a snippet of code the code I am using:
case IDC_BUTTON_ONE:
{
HANDLE hFile = CreateFile("C:\\test.txt", GENERIC_READ,
0, NULL, CREATE_NEW, FILE_FLAG_OVERLAPPED, NULL);
}
To write a control's text to a file you'll also need these lines:
char TextBuffer[256]; // Ascii
GetDlgItemTextA(hDlg, IDC_YOUR_CONTROL_ID, TextBuffer, ARRAY_SIZE(TextBuffer));
WriteFile(hFile, TextBuffer, strlen(TextBuffer), &SizeOut, lpOverlapped);
That'll just write plain old ASCII. If you want to use unicode and TCHARs (instead of chars) then you'll need to choose your encoding and write more than "just the bytes" from the text buffer.