Keyboard hooks - Problem - C# Discussion Boards

I have a struct to mimic a c++ struct...I have converted types as follows:
C++ C#
---- ----
WORD ushort
DWORD uint
char[] string

the imported function passes a pointer to the struct, fills it with fun-facts and gives it back more useful than before. The only thing I currently want out of this is the char[] member of the struct and things are not working out.

Here's what I have done:
- I am using CharSet.Auto in the structLayout and dllImport attributes.
- in the function prototype : "ref STRUCTTYPE structname"
- before calling the function, initializing struct by using "new"
- before calling the function, initializing the string by creating a StringBuilder buffer of appropriate size and "ToString-ing" it to the struct.string member.

problem is, when I call the function and access the string, it still contains the text that I used to initialize it in the first place.

I haven't done enough testing to determine the problem, but I wanted to see if you have any ideas. My first question is to verify that using a c# string to represent the c++ char[] is all cool. I think it should be.
[Edit] Sigh | :sigh:

Almost, need [MarshalAs(UnmanagedType.ByValTStr, SizeConst=256] because it is a fixed char array [/Edit]

What I was thinking of while typing right now, is this:
in c++ structs are reference variables. in c# they are value variables. if i wanted to pass a c# struct to a c++ function, i would use the ref modifyer. Since my function wants a pointer to the struct, should I be using something like "ref IntPtr structname" ???? is this my problem and my solution?
[Edit] D'Oh! | :doh:

not quite, should work with "ref STRUCTTYPE structname"... if the struct were represented using a class, then would need [In,Out] instead of ref. See link in next post for details. Can't wait to get home and try it![/Edit]

Tym!

I found this on MSDN (of all places) that I think will fix my problem. Maybe it will help someone else with a similar prob:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconmarshalingclassesstructuresunions.asp[^]

How can I make a ListView editable?
The LabelEdit property doesn't work with columns, when I double click a subitem just edit the first subitem, not the one I actually double clicked.

Rickard Andersson
Here is my card, contact me later!
UIN: 50302279
Sonork: 37318
Interests: C++, ADO, SQL, Winsock, 0s and 1s

You need to create a tableSyle, something like this:

DataGridColumnStyle itm;
DataGridTableStyle tableStyle = new DataGridTableStyle();
tableStyle.MappingName = dsErrorDetails.Tables[0].TableName;

itm = new DataGridTextBoxColumn();
itm.Width = 120;
itm.NullText = "";
itm.HeaderText = "header"
itm.MappingName = dsTables[0].Columns[y].ColumnName;
itm.ReadOnly = false;

tableStyle.GridColumnStyles.Add(itm);

So, you create an "itm" for your particular column that you would like to be editable. And set the ReadOnly to false. Here is where you can also adjust the width, sort, etc. of the column.

Hope this helps...

hm.. is this for a ListView? It looks like you do this for a DataGrid?

Rickard Andersson
Here is my card, contact me later!
UIN: 50302279
Sonork: 37318
Interests: C++, ADO, SQL, Winsock, 0s and 1s

Hi all.

I have written a very simple windows service where I have made overrides for OnStart, OnStop and OnShutdown. In the properties I have set CanStop and CanShutdown to true. The only thing that is to be done at the moment is that when either event is fired a line should be written to the log.

This works fine for OnStart and OnStop but it's like OnShutdown is never executed. Can anyone tell me what I'm doing wrong? This is my code:

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.ServiceProcess;

namespace MyServiceTest
{
public class MyService : System.ServiceProcess.ServiceBase
{
private System.Diagnostics.EventLog eventLog1;
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.Container components = null;

public MyService()
{
// This call is required by the Windows.Forms Component Designer.
InitializeComponent();

//Create event log
if(!System.Diagnostics.EventLog.SourceExists("MyServiceLogSourse"))
System.Diagnostics.EventLog.CreateEventSource("MyServiceLogSourse","MyServiceLog");

//register name of source
eventLog1.Source = "MyServiceLogSourse";
eventLog1.Log="MyServiceLog";
}

// The main entry point for the process
static void Main()
{
System.ServiceProcess.ServiceBase[] ServicesToRun;

// More than one user Service may run within the same process. To add
// another service to this process, change the following line to
// create a second service object. For example,
//
// ServicesToRun = New System.ServiceProcess.ServiceBase[] {new Service1(), new MySecondUserService()};
//
ServicesToRun = new System.ServiceProcess.ServiceBase[] { new MyService() };

System.ServiceProcess.ServiceBase.Run(ServicesToRun);
}

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.eventLog1 = new System.Diagnostics.EventLog();
((System.ComponentModel.ISupportInitialize)(this.eventLog1)).BeginInit();
//
// MyService
//
this.CanShutdown = true;
this.ServiceName = "MyService";
((System.ComponentModel.ISupportInitialize)(this.eventLog1)).EndInit();

}

/// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}

/// <summary>
/// Set things in motion so your service can do its work.
/// </summary>
protected override void OnStart(string[] args)
{
// Write to log
eventLog1.WriteEntry("MyService starts");
}

/// <summary>
/// Stop this service.
/// </summary>
protected override void OnStop()
{
// Write to log
eventLog1.WriteEntry("MyService stops");
}
protected override void OnShutdown()
{
// Write to log
eventLog1.WriteEntry("MyService shutting down");
}

}
}

Thanks
/EnkelIk

Sorry, left out a bit of information there: OnStart and OnStop executes when I start and stop the service manually. When I restart the computer OnStart is the only method that executes (when the service is automatically restarted); I expected at least OnShutdown to execute to.

/EnkelIk

I have a problem with keyboard hooks - every time i press hold the CTRL+SHIFT key for quite some time, my application will crash with the error message :

"An unhandled exception of type 'System.NullReferenceException' occurred in
system.windows.forms.dll

Additional information: Object reference not set to an instance of an
object."

I've searched high and low for a solution to this matter but to no avail. Here's the code that i am using, it is meant to disable keys like ALT+TAB, CTRL+ESC, etc:

protected delegate int LowLevelKeyboardProcDelegate(int nCode, int wParam, ref KBDLLHOOKSTRUCT lParam);

[ DllImport( "user32.dll", EntryPoint="SetWindowsHookExA", CharSet=CharSet.Ansi )]

protected static extern int SetWindowsHookEx(int idHook , LowLevelKeyboardProcDelegate lpfn, int hMod , int dwThreadId);

[ DllImport( "user32.dll")]
protected static extern int CallNextHookEx(int hHook,int nCode, int wParam, ref KBDLLHOOKSTRUCT lParam);

[ DllImport("user32.dll")]
protected static extern int UnhookWindowsHookEx(long hhook);

const int WH_KEYBOARD_LL = 13;
public struct KBDLLHOOKSTRUCT
{
public int vkCode;
int scanCode;
public int flags;
int time;
int dwExtraInfo;
}
protected int intLLKey = 0;

protected int LowLevelKeyboardProc(int nCode,int wParam,ref KBDLLHOOKSTRUCT lParam)
{
bool blnEat = false;

switch (wParam)
{
case 256:
case 257:
case 260:
case 261:
//Alt+Tab, Alt+Esc, Ctrl+Esc, Windows Key
if (((lParam.vkCode == 9) && (lParam.flags == 32))
|| ((lParam.vkCode == 27) && (lParam.flags == 32))
|| ((lParam.vkCode == 27) && (lParam.flags == 0))
|| ((lParam.vkCode == 91) && (lParam.flags == 1))
|| ((lParam.vkCode == 92) && (lParam.flags == 1))
|| ((true) && (lParam.flags == 32)))

{
blnEat = true;
}
break;
}
if (blnEat)
return 1;
else
{
return CallNextHookEx(0, nCode, wParam, ref lParam);
}
}
public void KeyboardHook()
{
intLLKey = SetWindowsHookEx(WH_KEYBOARD_LL, new LowLevelKeyboardProcDelegate(LowLevelKeyboardProc), System.Runtime.InteropServices.Marshal.GetHINSTANCE(System.Reflection.Assembly.GetExecutingAssembly().GetModules()[0]).ToInt32(),0);
}

Sir

i write a code in C#

char myChar='/u0634';

Console.WriteLine("Unicode Character is {0}",myChar);

but it not give the actual character of that unicode.

what's the problem pls any tell me.

Thanks in Advance.

Hi!

Console automaticaly convert string to OEM encoding and then type it in console window...

that is why not all unicode charecters can be converted and shown in console window.

try to do the same on WindowForm...

Good Luck
Alex Kucherenko

I have two ListViews, DataGrids whatever, and they both contain data from 2 seperate datasets. I'd like to have a scrollbar on one view that when scrolled would automatically adjust the other view so they both stay in sync. Both datasets would contain the same number of rows. Can this be done with C#.NET?

Fairly easily?
Any help/sample code would be greatly appriciated!
Thanks Smile | :)

C#, at least I think, is alot better than vc++6 since everything is soo easy to use and soo powerful. Smile | :)

<marquee>Universal Project... Soon to be a .net

So, you're saying that VB is better than C++?

Rickard Andersson
Here is my card, contact me later!
UIN: 50302279
Sonork: 37318
Interests: C++, ADO, SQL, Winsock, 0s and 1s

I'm not saying that since I myself is a c++ proggrammer. It's just that it is said that C# combines the power of c++ with the ease of vb, though I know that C# has some issues, I think that this will probably erase mfc and visual c++ 6 though it will be alive, it won't be the preffered language anymore, just wait a couple of years and you'll see how it will progress.
Wink | ;)

<marquee>Universal Project... Soon to be a .net

Snyp wrote:
I think that this will probably erase mfc and visual c++ 6 though it will be alive, it won't be the preffered language anymore, just wait a couple of years and you'll see how it will progress.

It will do progress, but will not erase C++, ever!

Rickard Andersson
Here is my card, contact me later!
UIN: 50302279
Sonork: 37318
Interests: C++, ADO, SQL, Winsock, 0s and 1s

GRR... I didn't say that it will KILL C++, I said that it won't be the preferred language...;)

<marquee>Universal Project... Soon to be a .net

Whatever, dude! Big Grin | :-D

Rickard Andersson
Here is my card, contact me later!
UIN: 50302279
Sonork: 37318
Interests: C++, ADO, SQL, Winsock, 0s and 1s

Ya ok

<marquee>Universal Project... Soon to be a .net

Hi ,
I am trying to add a WindowsMediaPlayer Control in my app so that the user can play the audio file from my app page ! I have added the ref to WMPLib.dll.

My code is as follows:

AxWMPLib.AxWindowsMediaPlayer newMedia = new AxWMPLib.AxWindowsMediaPlayer();

ResourceManager resources = new ResourceManager(typeof(testControl));
newMedia.OcxState = ((AxHost.State)(resources.GetObject("newMedia.OcxState")));

newMedia.Enabled = true;
newMedia.Location = new Point(tX, tY);
newMedia.Name = tName;
newMedia.Size = new Size(tW, tH);
thisPanel.Controls.Add(newMedia);
if (tDefault != null) newMedia.URL = tDefault;

newMedia.URL = @"c:\myfile.mp3";

The last line newMedia.URL = @"c:\myfile.mp3" results in InvalidActiveXStateException. I know the filename is correct as I can play it from Explorer.

Any suggestions Confused | :confused:

!?!

Thanks,
Paul

In ASP (Code behind module) I'm tring to so a simple assignment of a dropdownlist value to an int but it can't convert the string to int. So how would I cast this?

<br />
dgResult.PageSize = ddlPageResults.SelectedValue;<br />

I tried (INT) but that's C++ I couln't do the ToInt32 either it didn't look like. I know this is super simple but I couln't find an aswer.

Try converting the string to int with the Int32.Parse() method.

Hi,

you can try:

<br />
try {<br />
  int MyInt = Convert.ToInt32(MyString); // Try to convert whatever to int<br />
}<br />
catch(Exception ex)<br />
{<br />
// Hey That was not a number !<br />
}<br />

Good Luck !
Braulio

I have Data in a typed DataSet and a Form to Edit it.
First Time I edit the Data with the form everything works fine. But if I want to reedit the Data, as I first changes something by the form everything freezes, means that I can't change data in any Control on the form. Even the OK, Cancel Buttons doesn't work anymore. I have to exit by the Close Button of the Form.

Any Ideas?

hi,Does anyone know how to spread text over columns in a listview in c#?

THIS is EASY IN C++ .you ONLY have TO SET the SetItemData Method of the CListCtrl to 0.
IF you WANT text TO BE DISPLAYED IN COLUMNS SET SetItemData to 1.

example:

m_ListCtrl.SetItemData(0,0); //this lines makes text spread over columns

m_ListCtrl.SetItemData(0,1); //text to be displayed column by column

how can this be accomplished in c#?

thanks

I personally haven't worked with ListView controls in C#, but I did a quick search in MSDN and found a property called "Tag" in the ListViewItem class which may serve your purpose.

Regards,
Alvaro

Hey! It compiles! Ship it.