How can I write a signed byte (sbyte) to unmanaged memory using VB.NET? I can use Marshal.WriteByte() to write an unsigned byte, but there doesn't appear to be an overload for signed bytes.
View 1 RepliesI need to be able to write signed bytes to a serial port using SerialPort.Write() method, except that method only takes byte[] arrays of unsigned bytes, how would i write a signed byte to the serial port?For what I'm working on the particular command takes values from -1700 to 1700.
View 1 RepliesI would like to know how to convert a unisgned byte to signed byte
Atm I got this
a
Function readSignedByte() As SByte
'-128/127
Dim b As SByte
[Code]....
it doesn't work one that well works for numbers positive over 127 if lets say ReadByte() has 128 it would give overflow error which I don't want it to give I would like it to overflow the number to negivate value aka its signed value.
I have an array of Bytes. Most of these are interpreted as Unsigned. On certain occasions I need to interprete the byte as signed. Why can't Byte convert to SByte? What I'm doing: I'm trying to program a disassembler for an 8-bit video game ROM. My program reads the ROM and processes each instruction. The instructions are interpreted as unsigned. Some arguments for instructions would be treated by two's complement in the original hardware, however, to make a signed number.
View 8 RepliesI need to read signed and unsigned 8 bit, 16 bit and 32 bit values from a file stream which may be little-endian or big-endian (it happens to be a tiff file which carries the byte order indicator at the start).I initially started by writing my own functions to read the values and was able to do so for unsigned values. e.g.
Public Function ReadUInt32() As UInt32
Dim b(4) As Byte
input.Read(b, 0, 4)
[code]....
But then I started looking at signed values and my brain broke.As an alternative, I found the IO.BinaryReader which will let me read signed values directly but doesn't seem to have any way to indicate that the data is big-endian or little-endian.Is there a nice way of handling this? Failing that, can someone tell me how to convert multiple bytes into signed values (in both byte orders)?
I've been using a simple mouse hook and some accessiblity api stuff to retreive caption under mouse (ObjectFromPoint) and accessibility api for events (ObjectFromEvent).It seems like there is memory leaks with unmanaged callbacks.With the global mouse hook it seems there is 4 - 8k of ram added every time the mouse is just moved even though I only monitor mousedown and mouseup with:
Private Const WM_LBUTTONDOWN As UInteger = &H201
Private Const WM_LBUTTONUP As UInteger = &H202
Private Const WM_MBUTTONDOWN As UInteger = &H207
[code]....
And with accessibility it seems there is also memory issues with my code. Is this to do with delegates?I only managed to find one mention on the mouse hook issues which led me in to a dead end.A long shot and maybe not even needed but I was wondering, if these mem leaks can't be stopped, would it free up the memory if I used threads which could be exited and new ones started eg.mem usage 3000k of which 1000k is leaked mem (for round figures) I exit global mouse hook thread and start a new m-hook thread.would this free up the memory? If so, how would i do this, not use threading before.
I have a structure in VB.NET that has a dynamic array of double as a parameter. I am passing an array of structure (GElement) to a C++ DLL. I tried converting my array of GElement into a block of unmanaged memory, it works in VB.NET but crashes in my C++ DLL. I get the same error just trying to simply pass an array of GElement to my DLL instead of a Intptr.
Here is the error
0xC0000005: Access violation reading location 0x00000004
Here is my function and structure in the DLL:
void _stdcall TestGElement(GElement* ge,long& nbge){
nbge=5;
} struct GElement {
double Step2D;
double Step3D ;
[Code] .....
I know it is easier if the array inside the structure as an already defined constant size but that can't be the case here...
Im getting a problem with one of my programs I have made in visual basic.NET where it gives me a memory error when i debug the program in the IDE. the exact error is this: "Attempted to read or write protected memory. This is often an indication that other memory is corrupt". My program basically has a few forms with text fields on that get their text values from an access database on the same hard drive. Im wondering if im doing something wrong because my program just seems to eat up memory whenever it does anything. For example I have one form that has a combobox on it and when you change the drop down list selection it retreives a few strings from the database and puts them into the relevant text boxes, if you keep changing the selection then the memory usage (in task manager) just keeps going up and up. occasionally I get the error mentioned above when debugging but in my built version of the program it throws an exception everytime the memory usage gets past 49K.
Also I noticed when debugging in the "immediate window" frame I get the following message often:A first chance exception of type 'System. Invalid OperationException' occurred in System.Data.dll...Do I need to somehow be "releasing" the memory that is used to gather data once it becomes redundant?
I am using the following code
This error occurs :
Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
Public Class FormRegEnumValue
[CODE]......................
QuoteSystem.AccessViolationException was unhandled Message="Attempted to read or write protected memory. This is often an indication that other memory is corrupt." Source="System.Windows.Forms"
Im designing a web browser and i continue to receive this error after going to about 3 websites it crashes with that error.
I cannot use Visual Basic 2008 at all. When I go to "new project" and choose "Windows Form Application" I get this error.I have tried multiple uninstall/reinstall with no result.A microsoft reply to this suggested that I needed: " .NET Framework 2.0 Service Pack 1 " I checked, and I did not have the .netframework 2.0 service Pack 1.
When I tried to download and install the above from Microsoft.com, the istaller said that "it was not allowsed" and I was not able to install the service pack 1.
I tried Uninstalling net framework 3.5, 3.0, 2.0 and then reinstalling .netframework 2.0 sevice pack 1; then reinstalling Visual basic 2008 express edition. At the reinstall of Visual basic 2008, .netframework 2.0 sevice pack 1 is unistalled by .net framework service pack 2.When I check the foruims for simiar problems, the formus are mostly for Visual basic 5.0, or other programs that I do not have.
Here is the programs I have installed:
Operating system: Windows XP
Microsoft .net framework 1.1
Microsoft .NET framwork 1.1 Hotfix(KB928366)
Microsoft .Net Framework 2.0 Service Pack 2
[code]....
All the security updates and hotfixes for Widows XP.
I have two forms, Form1 and Form2. Form2 has a button to show OpenFileDialog. I call Form2 from Form1 by a button. My startUp Form is Form1. When i start debugging, i press my Form1's button to show my Form2, it shows, but when i click On Form2's Button to show OpenFileDialog it is giving me exception that
"Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
When i set my startup Form to Form2 and click Form2's Button to show OpenFileDialog then it shows!
I am getting the following error: "Attempted to read or write protected memory. This is often an indication that other memory is corrupt". i am using interop service.
View 2 Replieshow to convert byte array to memory stream in vb.net.
View 1 RepliesI am using IonicZip to compress video files and store in a blob field. I have the zip file created just need to convert it to a byte array. How is this done without writing to the harddrive?
View 1 RepliesHow to convert memorystream byte array to csv file. I have GetExport method that converts rpt file to excelformatted memorystream and then returns that as a byte array. Is there a way to convert this byte array to a csv file? Due to some reasons I can only pass this byte array back to calling function.
Public Function GetExport(ByVal reportID As ReportID) As Byte()
Dim byteArray As Byte() = Nothing
Using expRptDoc As ReportDocument = New ReportDocument()
Dim rptFileName As String = Server.MapPath(ReportCommand.GetXMLReportPath(reportID))
expRptDoc.Load(rptFileName)
[Code] .....
I am trying to copy a byte array into a Class that is in a third party library
Dim usr As New RSI_USER_RECORD Dim ba(RSI_USER_RECORD.RSI_LEN_USER_REC - 1) As Byte 'populate ba here usr = ba 'how can I do this? Is this even possible?
Here is the definition of the class (from Reflector)
[Code]...
I have a reportviewer that I am rendering as a pdf into an in memory byte array. What I need to do is apply an owner and user password for the pdf. I have downloaded the adobe sdk and have scoured the Internet for examples to do this to no avail. with a VB.NET example that will apply the owner and user password for the pdf.
View 2 RepliesI'm trying to get a string from a byte array previously read from memory
i can get the string like this
dim mem as string= ASCIIEncoding.ASCII.GetString(memory) or dim mem as string= UTF8Encoding.UTF8.GetString(memory) but when i try to concatenate this with another string i get a strange result dim result as string = "this is you memory string " & mem & " problem string" no matter what comes after mem in the concatenation it seems like it is not there when in fact it is because when i try this (mem has two chars in it) dim result as string = "this is you memory string " & mem(0) & mem(1) & " problem string" problem string appears so what i assume is that there are some vbCrLf chars in the string after reading (or is it from the conversion?)
We were currently working with our thesis regarding file compression and selected LZW compression. So far, we know how to work on it but we were stucked on how to write a byte.LZW uses 256 and up for the code table because 0 to 255 was used for a single byte.url...Our problem was we don't know how to write a byte higher than 255, s it possible, and read it as it is? Or, different way on how to do it?
View 1 RepliesHow do I read a raw byte array from any file, and write that byte array back into a new file?
View 3 Repliesi tried saving the string 1995030 to file as byte as a hex value.Used the following lines to do this by hand:
Dim fs As New FileStream("test.txt", FileMode.Open, FileAccess.ReadWrite)
fs.WriteByte(&H2D))
fs.WriteByte(&HB3)
fs.WriteByte(&H56)
This works as expected and everything is fine until this point.Now i tried to solve this problem by code.Tried the following:fs.writebyte(&H(str))Str contains the actual hex value to write.
I am trying to create a text file using VB.Net with UTF8 encoding, without BOM.
I can write file with UTF8 encoding but, how to remove Byte Order Mark from it?
edit1: I have tried code like this;
Dim utf8 As New UTF8Encoding()
Dim utf8EmitBOM As New UTF8Encoding(True)
Dim strW As New StreamWriter("c: empom1.html", True, utf8EmitBOM)
[Code]....
I have created an event DGVddlSubCategoryComboIndexChanged.as soon as the control come out of this event an error througn
Error:Attempted to read or write protected memory. This is often an indication that other memory is corrupted
Read/Write Process Memory?
View 6 Replieshow to write to memory some data and then read it back?
If i have 1GB free of memory i would like to write 100MB to memory some data and then read it back, i searched net for some documentations but cant find nothing, only writing to other process and some stupidities!
This is my 50th attempt to read the memory and probably my last attempt if I don't succeed now T_T I've been trying to write a class that reads from the memory, simply by creating wrappers around the Win32 APIs but I just can't get it to work.
This is how I currently am trying to read the memory from calc.exe:
Public Function ReadMemory(ByVal hProcess As IntPtr, ByVal lpBaseAddress As IntPtr, ByVal nSize As Integer, ByVal lpNumberOfBytesRead As Integer) As String
Dim tmpBuff As Single = 0
[Code]...
If you match two same colours or pictures, you get some points. There should be nine pairs of hidden pictures/colours but shows up when clicked but should not in the same order or line. There has to be a count down timer as well.
View 1 RepliesIs it possible to write the contents of a TextBox to memory so it is available in e.g. WORD or NOTEPAD and can be pasted using CTRL-V?
View 1 RepliesI have read the file into the memory.Now I need to copy this file into any folder that I have created.Can I use stream writer for doing that?
View 1 Replies