C# Discussion Boards - CodeProject

FilterSendMessage - talking to a MiniFilter driver

18-Sep-09 15:28

Hi,

assuming a TextBox, the basic principle is to provide a handler for the TextChanged event; in there, the text is used in a search command (say a SELECT * FROM ... WHERE ... in SQL) and the results are shown in a DropDown, a ToolTip, or whatever you choose.

So basically there is one database query for each character you type into the TextBox.

Smile | :)

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

Local announcement (Antwerp region): Lange Wapper? Neen!

Re: is it xml technology

Mohamed El-Wehishy18-Sep-09 15:40

Mohamed El-Wehishy

18-Sep-09 15:40

thanks very much dude
you answered my question Smile | :)

Søren Staun Jørgensen18-Sep-09 11:32

Søren Staun Jørgensen

18-Sep-09 11:32

Hi,
I'm trying to talk to a mini-filter driver using p-invoke, but cannot make this function return successfully:

C/C++ function:

HRESULT WINAPI FilterSendMessage(
    IN HANDLE  hPort,
    IN LPVOID  lpInBuffer OPTIONAL,
    IN DWORD  dwInBufferSize,
    IN OUT LPVOID  lpOutBuffer OPTIONAL,
    IN DWORD  dwOutBufferSize,
    OUT LPDWORD  lpBytesReturned
    );

C# function:

[DllImport("FltLib", CallingConvention = CallingConvention.Winapi, CharSet = CharSet.Auto)]
public static extern int FilterSendMessage(
   [In] SafeFileHandle hPort,
   [In] IntPtr lpInBuffer,
   [In] int dwInBufferSize,
   [In, Out] IntPtr lpOutBuffer,
   [In] int dwOutBufferSize,
   [Out] out int lpBytesReturned);

My problem is that whenever I call this function (in C# code) it returns 0x80070057 (Invalid parameter). The handle to the port is valid, and I have received a message from the filter just before this method is called.

I'm using it like this to send a message to the filter:

int bufferSize = Marshal.SizeOf(myBuffer);
IntPtr inBuffer = Marshal.AllocHGlobal(bufferSize);
int bytesReturned = 0;

Marshal.StructureToPtr(myBuffer, inBuffer, true);

int res = FltLib.FilterSendMessage(_hPort, inBuffer, bufferSize,
    IntPtr.Zero, 0, out bytesReturned);

// res = 0x80070057

Any help appreciated, thanks...

Soren

Re: FilterSendMessage - talking to a MiniFilter driver

Søren Staun Jørgensen18-Sep-09 11:45

Søren Staun Jørgensen

18-Sep-09 11:45

Ahhr - never mind, my bad!

It works fine passing the right buffer Smile | :)

Soren

unmanaged code data type equivalents in c#

akhanal18-Sep-09 11:00

akhanal

18-Sep-09 11:00

Hi,

I am using some unmanaged Dlls and need equivalent types when calling the functions in these DLLs from managed C# code:

For e.g.: const char** = ref string, const char* = string, char** = out IntPtr.

Does anyone know the equivalents for these?

int* = ?
char**** = ?
char*** = ?
float* = ?
uint64* = ?
double* = ?

thanks

Christian Graus18-Sep-09 11:39

Christian Graus

18-Sep-09 11:39

They are all inptr. Any pointer has the same space in memory, as it's a memory address. Then you need to marshall the intptr in your managed code to get the data it's pointing to. A char * is different, it's a string. So, a char ** is a pointer to a string. Hence, an IntPtr.

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

Luc Pattyn18-Sep-09 11:47

18-Sep-09 11:47

I tend to disagree somewhat. For value types a single indirection can easily be accomplished using the ref keyword; I do use IntPtr for reference types that either got fixed or GCHandle-pinned (with the exception for strings).

Here is a working example:

[DllImport("kernel32.dll")]
public static extern int GetDiskFreeSpaceEx(string rootPathName,
    ref long lpFreeBytesAvailable, ref long lpTotalNumberOfBytes,
    ref long lpTotalNumberOfFreeBytes);

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

Local announcement (Antwerp region): Lange Wapper? Neen!

Christian Graus18-Sep-09 12:16

Christian Graus

18-Sep-09 12:16

Yes, that would clearly work, hence, my 5

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

Matt Meyer18-Sep-09 12:21

Matt Meyer

18-Sep-09 12:21

One note to this - if you're passing a string into unmanaged code that's going to be written to, you should use a StringBuilder instead of a string.

Luc Pattyn18-Sep-09 12:32

18-Sep-09 12:32

I do. It even is my favorite way of returning a string: just pass a SB with sufficient capacity and have it filled.

Smile | :)

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

Local announcement (Antwerp region): Lange Wapper? Neen!

Help with getting data from web service into a named pipe stream

akhanal19-Sep-09 6:44

akhanal

19-Sep-09 6:44

thanks guys

AndyASPVB18-Sep-09 10:20

AndyASPVB

18-Sep-09 10:20

Hi
I have created a web service, and I need to pass this data into a named pipe stream, which connects to an external device.

My web service is working well, and I have a method to retrieve data from the web service, which I can bound to a datagrid successfully. This tells me it is working correctly, and I can see my data.

However, where I am stuck is how to convert the data from the web service into either a string or bytes for the pipe to use and what is best way place the data on a named pipe in .Net?

Can anyone show me how to do this?

Thanks

Does destination PC need installing Crystal Report ?

Mohammad Dayyan18-Sep-09 10:01

Mohammad Dayyan

18-Sep-09 10:01

Hi everybody.
I'm using Crystal Reports in my Win App project.
I want to execute my application on other computers.
I'd like to know , I have to install Crystal Report on destinations computers ? if so, where can I find the installer ?

Thanks.

Work on a new thread locks the GUI

SimpleData18-Sep-09 9:23

18-Sep-09 9:23

Hi I have an application which uploads files over FTP. I create a new thread and start uploading on that thread but GUI locks while this upload takes place. As far as I know because I am not uploading on main thread GUI should not lock and it should stay responsive.

What am I doing wrong? If you need the code please tell me.

Thanks.

Luc Pattyn18-Sep-09 9:48

18-Sep-09 9:48

it would be wrong to:
- have an event handler start the thread and wait for it to finish;
- have the thread touch any Control or windows-related Component, including Windows.Forms.Timer; this[^] explains it.

If neither apply, we will need to see some code.

Smile | :)

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

Local announcement (Antwerp region): Lange Wapper? Neen!

Manas Bhardwaj18-Sep-09 9:52

Manas Bhardwaj

18-Sep-09 9:52

Ah!!! there you are... just gave him the link to your one of the replies yesterday Smile | :)

Manas Bhardwaj
Please remember to rate helpful or unhelpful answers, it lets us and people reading the forums know if our answers are any good.

SimpleData18-Sep-09 10:00

18-Sep-09 10:00

Thank you for your answer. My thread is interacting with a progressbar. What would be the correct way to interact with the progressbar without locking the GUI?

Luc Pattyn18-Sep-09 10:03

18-Sep-09 10:03

why don't you read what I gave you?

Frown | :(

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

Local announcement (Antwerp region): Lange Wapper? Neen!

SimpleData18-Sep-09 10:06

18-Sep-09 10:06

Oh, sorry somehow I didn't see the link, it's getting late here Smile | :)

.

I am reading the article now.

SimpleData18-Sep-09 10:20

18-Sep-09 10:20

Thank you for showing me that article. It really helped me.