Re: Shut down explorer programmatically - C# Discussion Boards

13-Apr-05 8:18

I need to shutdown explorer programmatically. I had to do this once in a C++ project and I used the following code:

HWND hwndShell = NULL;
hwndShell = FindWindow("Progman", NULL); // Locate the Windows shell
if(hwndShell != NULL)
{
PostMessage(hwndShell, WM_QUIT, 0, 0L)// Tell the Windows shell to quit
}

Any ideas on how to do this in C#?

Thanks!

Ian

tommazzo13-Apr-05 8:42

tommazzo

13-Apr-05 8:42

You can do this using the System.Diagnostics namespace. The following code will kill explorer.exe:

Process[] RunningProcesses = Process.GetProcessesByName("explorer");
Process proc = new Process();
foreach(Process p in RunningProcesses)
{
if(p.ProcessName == "explorer")
{
proc = p;
break;
}
}
proc.Kill();

When I tested it however explorer.exe restarted a few seconds after it was killed. This might be due to some program I had running, but I'm not sure.

Ian Bowler13-Apr-05 8:48

13-Apr-05 8:48

Thanks alot! I wonder how you kill it for good? I want to control when it starts up again. Anyone know how to do that?

Thanks!

Ian

Dave Kreskowiak13-Apr-05 9:08

13-Apr-05 9:08

You can't. Explorer automatically restarts itself.

But, I seem to, vaguely(!), remember a policy somewhere that controls this. I can't find it and I can't remember where I saw it, though.

BTW: Why on earth would you want to do this anyway?

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Ian Bowler13-Apr-05 9:13

13-Apr-05 9:13

Why? It's a long story...

The C++ code in the original post shuts down explorer indefinately. Is the limitation a C# limitation?

tommazzo13-Apr-05 9:38

tommazzo

13-Apr-05 9:38

Ian Bowler wrote:
The C++ code in the original post shuts down explorer indefinately. Is the limitation a C# limitation?

This is, I believe, because you sent the process the WM_QUIT message, with Process.Kill() you kill it without sending it the WM_QUIT message.

In order to keep explorer from restarting you could either run a loop on a new thread, which continously checks if explorer has been restarted and kills it again if neccessary (this isn't really the best idea).
Or (and this should be the better idea) you could import the FindWindow and PostMessage methods with DllImport and use them the same way as in C++;

Ian Bowler13-Apr-05 9:39

13-Apr-05 9:39

Thanks! I'll give it a whirl...

-Ian

Dave Kreskowiak13-Apr-05 10:13

13-Apr-05 10:13

I've got time. Big Grin | :-D

Honestly, if an application killed off Explorer for me, without my permission, I'd want to know where on earth this person was who wrote it, for some very not-so-nice reasons...

Please tell me this isn't being deployed into the real world?

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Ian Bowler13-Apr-05 11:18

13-Apr-05 11:18

I understand your concerns and curiosity. I'm not going to be shutting down explorer all willy-nilly. There's a good reason for it in the context of what I'm working on.

For those of you that may wonder how this all turned out, I had to import the User32.dll functions, FindWindow and PostMessage (as tommazzo suggested). The final code looks like this:

public class Win32
{
public Win32(){}

[DllImport("User32.dll")]
private static extern IntPtr FindWindow(string ClassName,
string WindowName);

[DllImport("User32.dll")]
private static extern Boolean PostMessage(IntPtr hWnd,
uint Msg,
IntPtr wParam,
IntPtr lParam);

public bool ShutdownExplorer()
{
Boolean bSuccess = false;
IntPtr Handle = new IntPtr(0);
// Get a handle to explorer.exe
Handle = FindWindow("Progman", null);
// Shutdown explorer.exe
if(Handle != IntPtr.Zero) bSuccess = PostMessage(Handle,
0x0012,
IntPtr.Zero,
Ptr.Zero);
return bSuccess;
}
}

Thanks tommazzo for the solution. Thanks Dave for your insights.

Regards,

Ian

Dave Kreskowiak13-Apr-05 8:49

Weird Shelling Issue inside and out of IDE

13-Apr-05 8:49

tommazzo wrote:
When I tested it however explorer.exe restarted a few seconds after it was killed.

It's supposed to do this. By default, Explorer automatically restarts itself if it's shutdown without a user session logoff. Sometimes, though, it doesn't restart itself. When this happens, you can still hit Ctrl-Alt-Del, start the Task Manager, click on File/New Task (Run), then type CMD in the prompt, NOT EXPLORER! Instead, type CMD and in the resulting command window, type START EXPLORER.

For some reason, if Explorer crashes and you type EXPLORER in the Start/Run box, it won't restart. Though, typing the START EXPLORER command in a CMD window works. Wierd...

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

CyberTech13-Apr-05 7:34

CyberTech

13-Apr-05 7:34

I am writing a frontend to the ffmpeg program so I can convert multimedia files to a Playstation Portable format. I am using the Process Class with redirected outout so I don't have a console window popup. Now if I run the Program Through the IDE (Debug or Release) it works flawlessly. If I run the generated exe outside of the IDE I get errors from the program and the conversion does not complete or even do anything wright. I know this could be a ffmpeg issue but the only difference from working and not working is the IDE execution. I have checked the environment variables and there is only one difference a debug varibale is set in the IDE and I have artificaly set that just to see if that would work and it didn't.

Any Ideas?
Thanks
Cyber

Dave Kreskowiak13-Apr-05 7:52

13-Apr-05 7:52

There's more than just the IDE being there or not, the current directory also changes. So, I have a couple questions...

Does your application supply the full paths or all the files involved with ffmpeg? Does your code consider than ffmpeg might fail and log everything that came out of the session into a file somewhere? What errors are returned by ffmpeg when you shellexecute it?

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

CyberTech13-Apr-05 8:00

CyberTech

13-Apr-05 8:00

Here is my Code:

Process P2 = new Process();
P2.StartInfo.UseShellExecute = false;
P2.StartInfo.FileName = Environment.CurrentDirectory + @"\ffmpeg.exe";
P2.StartInfo.WorkingDirectory = Environment.CurrentDirectory;
P2.StartInfo.RedirectStandardOutput = true;
P2.StartInfo.RedirectStandardError = true;
P2.StartInfo.Arguments = strCmd;
P2.StartInfo.CreateNoWindow = true;
P2.Start();

There is not exit code like info the program just can't read the input files correctly. I do have all the files in the Environment.CurrentDirectory and have even at one point appended the Environment.CurrentDirectory to the Environment Variable "PATH" statement.

Also if I allow the console box to appear with the redirect turned off. It works on both situations.

Thanks,
Cyber

Dave Kreskowiak13-Apr-05 8:40

13-Apr-05 8:40

I didn't ask for an exit code. I asked if you were reading the redirected output and dumping it into a file for later review. If the program can't read the files, or any other error ffmpeg complains about, it would be displayed in either one of the streams. If you were reading those streams, then the output could be dumped into a file for debugging.

Now, since your doing this to prevent a console window from showing up, it's entirely possible that ffmpeg doesn't support that. It might actually need a console window because the app is trying to write directly to the screen buffer in that window. If there is no console window, no screen buffer. No screen buffer, BOOM!

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

CyberTech13-Apr-05 8:46

CyberTech

13-Apr-05 8:46

I am capturing both streams into a RichTextBox for Debugging and no usefull info is in there for finding out what is going on.

Quote
"Now, since your doing this to prevent a console window from showing up, it's entirely possible that ffmpeg doesn't support that. It might actually need a console window because the app is trying to write directly to the screen buffer in that window. If there is no console window, no screen buffer. No screen buffer, BOOM!"

It works fine if I use the the Debug Start option from the Menu.
Thanks,
Cyber

Dave Kreskowiak13-Apr-05 9:13

C# WinForm - HTML Browser

13-Apr-05 9:13

In that case, I have no idea what's going on. I've never had a problem shelling another process like this.

The only thing I can think of is don't use the CurrentDirectory. I've always used full path specifiers for all of my file access. Even the ones that are used as command line parameters in other programs. I just don't believe in leaving something like the "CurrentDirectory" to chance and calling it "reliable."

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

AnneThorne13-Apr-05 6:49

AnneThorne

13-Apr-05 6:49

Hi,

I am using Syncfusion.Windows.Forms.HTMLUI.HTMLUIControl() to open a specific url in an html browser. The documentation gives me an example that does work; however, I want to modify it so that the url is automatically displayed when the winform is rendered.

Here is what works (NOTE: The ... indicates code that I have not shown here, for brevity's sake):

<br />
...<br />
#region Windows Form Designer generated code<br />
...<br />
private void InitializeComponent()<br />
{<br />
...<br />
    this.textBox1.Text = "http://www.google.com";<br />
...<br />
}<br />
...<br />
<br />
[STAThread]<br />
static void Main() <br />
{<br />
	Application.Run(new Form1());<br />
}<br />
<br />
private void textBox1_KeyPress(object sender, System.Windows.Forms.KeyPressEventArgs e)<br />
{<br />
if( ( ( int )e.KeyChar ) == 13 )<br />
	{<br />
		LoadDocument( textBox1.Text );<br />
	}<br />
}<br />
<br />
private void LoadDocument( string path )<br />
{<br />
	if( path == null )<br />
		throw new ArgumentNullException( "path" );<br />
<br />
	if( path.Length == 0 )<br />
		throw new ArgumentException( "path - string can not be empty" );<br />
<br />
	try<br />
	{<br />
		Uri uri = new Uri( path );<br />
		htmluiControl1.LoadHTML( uri );<br />
	}<br />
	catch( Exception )<br />
	{<br />
		ShowError();<br />
	}<br />
}<br />
...<br />

Again, what I want, is to have the url automatically loaded when the winform is rendered and eliminate the textbox and the need for the user to press the enter key.

Thank you in advance for any help you can give me.
Anne

Re: C# WinForm - HTML Browser

Dave Kreskowiak13-Apr-05 7:48