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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.
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!
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thanks very much dude
you answered my question 
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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);
Any help appreciated, thanks...
Soren
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Ahhr - never mind, my bad!
It works fine passing the right buffer 
Soren
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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
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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.
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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!
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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.
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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.
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I do. It even is my favorite way of returning a string: just pass a SB with sufficient capacity and have it filled.
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!
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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
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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.
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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.
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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.
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!
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Ah!!! there you are... just gave him the link to your one of the replies yesterday
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.
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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?
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why don't you read what I gave you?
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!
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Oh, sorry somehow I didn't see the link, it's getting late here .
I am reading the article now.
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Thank you for showing me that article. It really helped me.
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SimpleData wrote: What am I doing wrong? If you need the code please tell me.
You should rather try to use Backgroundworker [^]class.
In between, you should also read a great reply from Luc [^]to one one the questions couple of days back. This would also help you get you things clear.
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.
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Thank you for your answer but your second link is the same as first.
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Sorry, for the wrong link. This [^]is the one.
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.
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excuse me, but I don't feel responsible for that MS link at all... 
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!
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Luc Pattyn wrote: excuse me, but I don't feel responsible for that MS link at all
Oops!!! I meant this [^]
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.
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