How can I copy from a structure to the memory referenced to by a pointer back and forth?I need to do it with an offset.
Dim g_memoryPointer As IntPtr
Dim teArgs(10) as ArgumentStructure 'a structure defined somewhere outside my prog
Dim ix as Long, offset as Long
[code].....
Private Declare Function src_simple Lib "libsamplerate.dll" (ByVal data As IntPtr, ByVal converter_type As Integer, ByVal channels As Integer) As Integer<br/>
Private Declare Function src_strerror Lib "libsamplerate.dll" (ByVal err As Integer) As IntPtr<br/>
<br/>
<StructLayout(LayoutKind.Sequential, Pack:=1)> _
[code]....
I am trying to use VirtualQueryEx to read the memory of a process (first instance of notepad in this case). This function returns a pointer to the MEMORY_BASIC_INFORMATION structure. I am trying to read this structure.But everytime I try to access a member of the structure, I get a zero, which indicates I am messing something up.I am copying my code here.
-Coder_in_distress
Imports System.Runtime.InteropServices
Module Module1[code].....
i need to call this c++ function
HCTRegisterReceiver( &ReceiverInfo, &m_rid )
ReceiverInfo is structure
m_rid is DWORD
this is the stucture in and m_rid variable declaration in vb.net
Public Const WM_USER As Long = &H400
Public Const WM_HCTNOTIFY As Long = WM_USER + 9[code]....
I've noticed that every time I start a new thread in my program, the memory usage jumps about 1000k and it never goes back down. I have ensured that the thread is no longer running, and only one instance of my worker thread is ever running at a time. I am using ThreadPool.QueueUserWorkItem and ASyncOperation to get stuff done. The program starts using a Sub Main in a module that uses STAThread; I read that using STAThread instead of MTAThread makes it impossible for the Garbage Collector to get in and consider objects for garbage collection. However, when I change the STAThread to an MTAThread, the WebBrowser control in my frmMain cannot be instantiated.
I get this exception:
Code: An unhandled exception of type 'System.Threading.ThreadStateException' occurred in System.Windows.Forms.dll
Additional information: ActiveX control '8856f961-340a-11d0-a96b-00c04fd705a2' cannot be instantiated because the current thread is not in a single-threaded apartment. I do threading with the WebBrowser control, so will using MTAThread fix my problem? If so, how should I partition my code so that the WebBrowser control won't be affected by the above exception? I call the thread repeatedly with a timer (although only one instance ever runs at a time), and my program's memory usage starts at about 5000k and can jump to 300,000k+ depending on many times the thread needs to be called.
I'm making a "wrapper" for an unmanaged DLL (written, I'm fairly certain in C). I have a c++ "wrapper" that I'm trying to convert to VB.net. I've got most of the program working, but I've hit a brick wall.
I'm trying to convert the following two structures from their c++ versions to their vb.net versions. I cannot be sure which is the problem because both must be passed at the same time. The error I am getting is thrown by the object and indicates "Invalid structure size specified". I can cause this error on other objects when I either don't set the dwSize variable, leave off a parameter or change the parameter type incorrectly. Note that the dwSize parameter is supposed to contain the size of each structure. I'm successfully calculating that for my other structures and I'm using the same method on these and the results appear correct, so I do not believe the problem is found there. The object uses a lot of structures and the rest of them are working. These two are the only ones with a) an unsigned character pointer b) an unsigned long array and c) doubles.
C++ versions:
CODE:
I don't think I'm missing any parameters - the help file seems to agree with me on this, but it's theoretically possible that there is something missing (though I don't think so for other reasons as well). My suspicion is that it's dwPalette, pImageData or pMaskData with (in my uninformed opinion) more suspicion on the pImageData and pMaskData.
I tried to translate this code to vb.net using Marshal.copy but I can't get it to work
for (int y = 0; y < bitmapdata.Height; y++)
{
byte* destPixels = (byte*)bitmapdata.Scan0 + (y * bitmapdata.Stride);
[Code]...
What is the best way to get a structure from memory, I know the format:
[Code]...
The structure is 53 bytes until the chat text, the message length is determined by one of the structure variables LineLength, so what is the best way to get that and put into into a structure?
I was wondering if there was a way to find out how much memory a data structure too up. So say I declared a list of strings.
Dim theRN As New Dictionary(Of String, Integer)
Say it had 25 elements in it. How to find out how much memory those 25 elements are costing me?
I'm writing a application that has to check live what's going on somewhere. The data is stored in a integer array.But this data comes from a PLC over a COM port. So imagine if someone pulled out the cable while my application is running. I have to find a way that the integer array will be stored somewhere when my application crashes. I thought maybe I could do something with a text file? But how do I get my application to store the data when it crashes? Do I have to surround my whole code with a try catch and then in the catch save everything to a text file? Well I like to know if some of you have better ideas or can point me in the right direction.
View 4 RepliesI am adding a web interface (ASPX.NET: VB) to a data acquisition system developed with LabVIEW which outputs raw data files. These raw data files are the binary representation of a LabVIEW cluster (essentially a structure).LabVIEW provides functions to instantiate a class or structure or call a method defined in a .NET DLL file.I plan to create a DLL file containing a structure definition and a class with methods to transfer the structure.When the webpage requests data, it would call a LabVIEW executable with a filename parameter. The LabVIEW code would instantiate the structure,populate the structure from the data file, then call the method to transfer the data back to the website.
How do you recommend I transfer (copy) an instance of a structure from one .NET program to the VB.NET program that executed it?
I am trying to copy/paste a structure to the clipboard the copy appears to work but the paste errors with "COMException crossed a native/managed boundary ErrorCode = -2147467259".The error occurs on the highlighted code line below. Is it possible to put a structure on the clipboard?
Public Structure Obstacle
Dim Type As obs
Dim Deleted As Boolean
[code].....
I am copying data from DataTable to another DataTable with a structure.I have to hardcode coulums number in the loop and copy the data in object array.[code]...
View 2 RepliesHere is the:
Imports System.Data.OleDb
'Add reference to Access then
Imports Microsoft.Office.Interop
Imports Microsoft.VisualBasic
[CODE]...
I am using this to copy tables in an Access database(2003). the questions I have are:
1. How can I make this more 'obejct oriented'?
2. How can I copy just the structure of the tables and not the data?
(Currently both are occuring)
unfortunately I cannot resort to C# in my current project, so I'll have to solve this without the unsafe keyword.I've got a bitmap, and I need to access the pixels and channel values directly. I'd like to go beyond Marshal.ReadByte() and Marshal.WriteByte() (and definitely beyond GetPixel and SetPixel).Is there a way to put all the pixel data of the bitmap into a Byte array that works on both 32 and 64 bit systems? I want the exact same layout as the original bitmap, so the padding for each row (if it exists) also needs to be included.Marshal doesn't seem to have something akin to:
byte[] ReadBytes(IntPtr start, int offset, int count)
Unless I totally missed it..
I have an open source project I converted to vb.net. I solved all the errors, except for one. This is the C# line
[Code]....
I want to copy files with a specific extension (for example .config or .exe). It should create a structure of nested directories, and then insert each file into a specified place in the directory hierarchy. Ideally I would just specify a parent directory for each file and a parent directory for each directory and it would build it.
I need any existing utility or batch file or power-shell script or C#/VB .Net code to perform this activity.
I have to automate a program that is outside of my control. The way I'm doing this is to use SendKeys.SendWait("keys") to the other program. The problem is, there are multiple fields that might be active and no way to select a single one with confidence. The fields are all different lengths, so my solution is to copy something really long, copy it to the clipboard, and look at the last character that made it though, so I know which field is selected in the other program. This overrides the clipboard, unfortunately.
[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]...
In my project when someone logs in I refresh the overhead and side menus. My overhead menu is an extended menustrip component that I have made. I am able to clear the menu, reload it dynamically but I am not able to add/insert the open windows which are managed by the mdiwindowlistitem property. These are the items named "1 - form name " "2 - form name" etc.
I have been able to copy the whole dropdown list, and with some very hacky loop work I can take out everything but the items related to the forms. But when I add them back in, they are not on my list. The related forms are still open and if you click the maximize button to shrink a open child window, and then re-maximize that same window...the items magically show up in the list.
This ManageMenus sub is called during a login change. If you breakpoint on "openwindowslist" after it is returned with data, it has the proper entries and nothing extra. It just seems that the for/each add loop does not actually add the items. Or, if it does add them, I can't see them.
Tried both insert and add functions, same results both ways.
CODE:
In my xmlMenuStrip component this is the function that removes everything but what follows the seperator. It returns them in a list.
The format of the full window menu is:
CODE:
I get this error on this line: System.Runtime.InteropServices.Marshal.Copy _
(Scan0, Data2, 0, Data2.Length)
"Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
I also sometimes get an error on this line:
Dim dc1 As IntPtr = CreateDC("DISPLAY", Nothing, Nothing, CType(Nothing, IntPtr))
What I'm trying to do is take a screenshot and then read the colors of pixels. I currently have a working vb.net copyfromscreen method but it's SLOW and using 100% cpu usage.
[Code]...
How can I declare pointer to pointer in ATL. Actually I have a handle which I want to pass by address to function. As shown below
STDMETHODIMP Function(HANDLE* hHC) //HANDLE declared as void * so actual type is void **
OR
STDMETHODIMP Function(LONG **hHC)
And want to access this function from the VB client.
Module Module1
Public Structure structure1
Public TRANS() As structure2
End Structure
Public Structure structure2
Public X() As Integer
End Structure
End Module
I'm new to VB 2008 after having spent a long time with VB6, so I apologize if this is a stupid question. But I'd really like to have this straightened out.
Let's say I have a pretty large structure that has lots of properties.
Code:
Now say that I want an internal database with about 10 instances of this structure total, describing, say, 10 different products that a store sells. When these values are loaded from a database, they remain totally static. (However, they can be different each time a program loads)
Now say that I have a class. Each instance of this class is a type of that BaseProduct structure. Meaning, each instance of the class pertains to one of the 10 types of products that the store sells. However, this class has additional properties that pertain specifically to each instance, which are not static.
Code:
Now, the problem here is... If I have 200 different transactions, each one contains an instance of BaseProduct. BaseProduct is HUGE, and is largely redundant (only 10 types possible), so I think it's a little silly to include a whole copy of it with EVERY transaction. However, the Transaction class really needs information regarding the base product it pertains to. Is there a way to, instead of declaring a New BaseProduct in the Transaction class, to simply make one of the properties of the Transaction class a pointer to a BaseProduct variable?
In VB6, I would accomplish this by making a BaseProduct(10) array, and then giving each Transaction an ID number referring to an entry in that array. But in VB 2008, using class structure, this is impossible. I can't define the BaseProduct(10) array outside of a class in a namespace, and if I define it in the actual application's form, then the class loses modularity since it relies on the application that's using it.
I am trying to communicate with an external device and i am trying to send a byte array to the external device via sockets but i am always getting a response the message size is too small so i am not sure what i have done wrong. Between the data type there should be no alignment present and all numbers are represented in little endian format. The char array is not null terminated as mentioned in the protocol specifications.
I have to send data based on a struct that embeds 2 other struct. So here's my vb.net code for the struct used to convert to byte array and the sending part.
Public Structure MESSAGETYPE_OIP_Login
Dim Header() As COMMANDHEADER
Dim UserName() As PSTRING
[Code]....
I'm experiencing a problem with the following c-structure:
typedef struct tagTEXTUREPROP
{
DWORD dwSize;
[Code].....
The Marshal.SizeOf obviously calculates a size of 76 and it works with the DLL function, but it leaves me with some bad feelings.
I'm having a problem that's driving me crazy; I can't understand how to convert the XML structure into a class structure (that I want to use to hydrate a XML document).
The XML document looks like this:
xml
<?xml version="1.0" encoding="utf-8"?>
<artists xmlns:opensearch="http://a9.com/-/spec/opensearch/1.1/" xmlns="http://www.spotify.com/ns/music/1">
[code]....
In VB 2005, I am calling a C++ DLL function that returns the address in memory and size in bytes of a jpeg image. How can I load that jpeg image directly from memory into a picture box in my VB form? I cannot afford to save it to disk first.
View 10 RepliesIm 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]......................