Re: How can I dictate the position of the run prompt? - C# Discussion Boards

Re: How can I dictate the position of the run prompt?

turbosupramk329-Apr-14 2:35

29-Apr-14 2:35

I believe the MainWindowHandle value of 0 is what is making this tough for me. Here is what I am seeing and this is what I had encountered before, no way to rectify what I'm seeing in spy++ to what I have when I enumerate through the process information. I still think the limitation is me though and not Windows or else how would spy++ have the alphanumeric value in the handle box?

http://s26.postimg.org/jlajsrx49/run_Prompt_Step_Through1.png[^]

Re: How can I dictate the position of the run prompt?

Alan N29-Apr-14 6:14

Alan N

29-Apr-14 6:14

You haven't said how you are trying to get the handle of the Run window but it is possible with the native function EnumWindows.

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

public class ProcessWindowFinder {
  [DllImport("user32.dll", SetLastError = true)]
  [return: MarshalAs(UnmanagedType.Bool)]
  static extern bool EnumWindows(EnumWindowsProc callbackMethod, IntPtr state);

  [DllImport("user32.dll")]
  static extern UInt32 GetWindowThreadProcessId(
    [In] IntPtr hwnd,
    out UInt32 processId);

  delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr state);

  public void FindWindows(Process selectedProcess) {
    EnumWindows(SelectWindowsByPID, (IntPtr)selectedProcess.Id);
  }

  private bool SelectWindowsByPID(IntPtr hwnd, IntPtr state) {
    Int32 pid = state.ToInt32();
    Int32 windowPid = GetWindowPID(hwnd);
    if (pid == windowPid) {
      // Do something here,
      // e.g. raise an event to pass hwnd to subscribers
    }
    return true;
  }

  private Int32 GetWindowPID(IntPtr hwnd) {
    UInt32 PID;
    GetWindowThreadProcessId(hwnd, out PID);
    return unchecked((Int32)PID);
  }
}

The callback function SelectWindowsByPID filters the handles down to those belonging to the selected process, in your case rundll32. You could filter further by window text (native GetWindowText) and visibility (native IsWindowVisible) but I think that final application specific filtering should really be done outside the ProcessWindowFinder class which is why I suggest raising an event.

Alan.

Re: How can I dictate the position of the run prompt?

turbosupramk329-Apr-14 9:14

turbosupramk3

29-Apr-14 9:14

Hi Alan,

Thanks for the reply. I'm trying to figure which function to plug information into, to test the code you posted.

If it is EnumWindowsProc(IntPtr hWnd, IntPtr state);, I don't have the hWnd? Can you lead me a long a little more please?

Re: How can I dictate the position of the run prompt?

Dave Kreskowiak29-Apr-14 10:36

Dave Kreskowiak

29-Apr-14 10:36

For some reason, you seem obsessed with passing a window handle into a function to find another window handle. You just need the Caption of the window:

[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

private void button1_Click(object sender, EventArgs e)
{
    IntPtr runHandle = FindWindow((string)null, "Run");
    Debug.WriteLine(string.Format("Run window handle: {0}", runHandle.ToString()));
}

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Re: How can I dictate the position of the run prompt?

turbosupramk330-Apr-14 6:02

turbosupramk3

30-Apr-14 6:02

I'm not obsessed with anything but learning. Here is what the IDE told me when I tried that code.

"Unable to find an entry point named 'FindWindow' in DLL 'user32.dll'."

Re: How can I dictate the position of the run prompt?

Dave Kreskowiak30-Apr-14 8:16

Dave Kreskowiak

30-Apr-14 8:16

What does your copy of the code look like? FindWindow has been in user32.dll since the beginning of Windows.

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Re: How can I dictate the position of the run prompt?

turbosupramk330-Apr-14 8:49

turbosupramk3

30-Apr-14 8:49

I closed and reopened the solution and it worked? Thank you for this, it was such a simple solution, I believe I tried something similar before originally posting but if I remember correctly I would always get a handle of 0 ... it turns out there is a slight delay/lag so before FindWindow will work on a spawned process, as the process has to load. I was not able to figure that out before, but was after you posted your code. Thank you.

@Alan, if you read this, I would still like to learn how your class ties together, and how it could be tweaked. Smile | :)

private void btnTest_Click(object sender, EventArgs e)
        {
            Process p = Process.Start(@"c:\Windows\System32\rundll32.exe", "shell32.dll,#61");

            int timeOutCounter = 0;
            IntPtr runHandle = IntPtr.Zero;
            do
            {
                runHandle = FindWindow((string)null, "Run");
                Thread.Sleep(100);
                timeOutCounter = timeOutCounter + 1;
            } while ((runHandle == IntPtr.Zero) && (timeOutCounter < 30));
          
            if (runHandle != IntPtr.Zero)
            {
                SetWindowPos(runHandle, 0, 800, 800, 425, 235, 0X4 | 0x0040);
            }
              

           
        }

Re: How can I dictate the position of the run prompt?

Alan N29-Apr-14 11:25

Alan N

29-Apr-14 11:25

OK,
The only public method in the class is FindWindows. It calls the native EnumWindows method which enumerates all top level window handles and for every window handle found a callback method is invoked. The method, which has the signature bool EnumWindowsProc(IntPtr hwnd, IntPtr state), is SelectWindowsByPID.

So some code that starts the process you are interested in and then enumerates the window handles,

Process p = Process.Start(@"c:\Windows\System32\rundll32.exe",  "shell32.dll,#61");
ProcessWindowFinder finder = new ProcessWindowFinder();
finder.FindWindows(p);

On my system 267 window handles were found and SelectWindowsByPID was invoked once for each of those handles. The filtering by process ID showed that only 3 were associated with the rundll32 process.

To determine which of those 3 handles identifies the "Run" window use the native GetWindowText function. There is an example c# method on pinvoke.net http://www.pinvoke.net/default.aspx/user32/GetWindowText.html[^]. For testing insert your code inside the if block where I inserted the comment // Do something here.

Alan.

Re: How can I dictate the position of the run prompt?

turbosupramk330-Apr-14 6:11

turbosupramk3

30-Apr-14 6:11

Hi Alan,

This is quite humbling. I honestly cannot figure out how to modify your class, ashamedly.

What I am trying to do is to get the class to return a list of hwnds and pids and then I was going to use GetWindowText to narrow down the proper hwnd while parsing through that list, as I am getting 4 or 5 handles found. This may be the wrong way to go about this, and this might be why I am having such trouble with it.

Using a Messagebox.Show in place of the // Do something I was able identify the proper pid and handle associated with it, but embarrassingly, I cannot figure out how to create an array of some sort, add each handle found and then return it to my calling function so that I can then parse through the returned data. I cannot figure out how this part of the code works

EnumWindows(SelectWindowsByPID, (IntPtr)selectedProcess.Id);

when SelectWindowsByPID requires two parameters by delclaration

IntPtr hwnd, IntPtr state

and I see that it somehow interacts with a static extern, which I have never used before. I apologize for my ignorance, but I'm self taught and apparently have discovered a large hole in my learning.

Re: How can I dictate the position of the run prompt?

Alan N1-May-14 3:12

Alan N

1-May-14 3:12

I see you've got Dave's FindWindow suggestion working and it's certainly a lot simpler than my method.

As you asked about EnumWindows here goes, although you may have to do some reading yourself, as getting callback functions to work reliably requires some advanced techniques.

First part of the answer on how EnumWindows works

EnumWindows(SelectWindowsByPID, (IntPtr)selectedProcess.Id);

The .NET program calls EnumWindows and supplies a method that will be called by Windows for every handle that is found. This is the callback method, the c# signature of which is fixed as

delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr state);

Windows sets the first parameter to the window handle it has found. The second parameter is a copy of the second argument supplied to EnumWindows, which provides a way for the programmer to pass information into the callback. I've used it to pass in the process Id.

Fully operational examples have additional complexity as it is essential to stop the .NET garbage collector moving any object that is referenced by the callback function. Rather than modify the original code I'll show you a complete class that gives a list of window handles.

using System;
using System.Runtime.InteropServices;

/// <summary>
/// Get a list of window handles associated with a specific process ID
/// </summary>
public class ProcessWindowList2 : System.Collections.Generic.List<IntPtr> {

  [DllImport("user32.dll", SetLastError = true)]
  [return: MarshalAs(UnmanagedType.Bool)]
  private static extern bool EnumWindows(EnumWindowsProc callbackMethod, IntPtr state);

  private delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr state);

  [DllImport("user32.dll")]
  private static extern UInt32 GetWindowThreadProcessId(
    [In] IntPtr hwnd,
    out UInt32 processId);

  private readonly Int32 pid;

  private static Int32 GetWindowPID(IntPtr hwnd) {
    UInt32 PID;
    GetWindowThreadProcessId(hwnd, out PID);
    return unchecked((Int32)PID);
  }

  private static Boolean SelectWindows(IntPtr hwnd, IntPtr state) {
    GCHandle gch = GCHandle.FromIntPtr(state);
    ProcessWindowList2 list = (ProcessWindowList2)gch.Target;

    Int32 windowPid = GetWindowPID(hwnd);
    if (list.pid == windowPid) {
      list.Add(hwnd);
    }
    return true;
  }

  /// <summary>
  /// Create and populate a list of window handles associated with a process
  /// </summary>
  /// <param name="processId">The process Id</param>
  public ProcessWindowList2(Int32 processId) {
    this.pid = processId;

    EnumWindowsProc callback = new EnumWindowsProc(SelectWindows);

    GCHandle gch = GCHandle.Alloc(this);
    try {
      EnumWindows(callback, GCHandle.ToIntPtr(gch));
    } finally {
      gch.Free();
    }
  }
}

This is a modified version of published code http://msdn.microsoft.com/en-us/magazine/bb985713.aspx[^]. It's derived from List<IntPtr> but has a special constructor that populates the list with handles. The code makes use of GCHandle.Alloc(this) to inform the garbage collector that objects of this class must not be moved until GCHandle.Free is called. This is essential for the safe operation of the callback.

Using the class is very simple

Process p = Process.Start(@"c:\Windows\System32\rundll32.exe", "shell32.dll,#61");
ProcessWindowList2 hwndList = new ProcessWindowList2(p.Id);
foreach (IntPtr hwnd in hwndList) {
  // do something
}

Have fun!

Alan.

Re: How can I dictate the position of the run prompt?

turbosupramk32-May-14 1:46

turbosupramk3

2-May-14 1:46

Thank you very much for taking the time to explain this Alan. This is completely new to me and I have a lot to read and learn about, but each time I read your post it becomes a little more clear. Hopefully I'll be able to come back and read this in a few weeks and understand it fully as I fill in this hole in my c sharp knowledge.

-Brad

Implementing transaction in MVC as Attribute

nitin_ion28-Apr-14 0:12

nitin_ion

28-Apr-14 0:12

Hi Can i implement transaction in MVC using EDMX like this link

[Handling Transactions]

Re: Implementing transaction in MVC as Attribute

Dave Kreskowiak28-Apr-14 3:18

Dave Kreskowiak

28-Apr-14 3:18

You could, but EF already wraps every batch of updates (when you call DbContext.SaveChanges) in a transaction by itself.

You get more control over this process if you're using EF6.0 or above. Read this[^] for more information.

Before you get into doing your own transactions you might want to read this[^].

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How to debug small programs

Dave Kreskowiak

Re: Implementing transaction in MVC as Attribute

nitin_ion28-Apr-14 17:19

nitin_ion

28-Apr-14 17:19

i know this but problem with this is mostly these calls are in DAL.
IN General you call ur business function from controller and there are multiple calls made which should be in transaction e.g.

using(Transaction.....)
{
BLL.SomeFunction1()
BLL.SomeFunction2()
}

Re: Implementing transaction in MVC as Attribute

Dave Kreskowiak28-Apr-14 17:55

Dave Kreskowiak

28-Apr-14 17:55

OK, that's still a bit backwards. The controller should be concerned with translating between the View (ViewModel) and the Business Logic, not controlling a transaction which is something that belongs in the Data Layer and possibly controlled by the Business Logic.

So long as the last call you make in the Business Logic is the DbContext.SaveChanges, all the changes the Business Logic makes will be wrapped in a Transaction AUTOMATICALLY. You don't have to create a transaction yourself!

public class BusinessLogic
{
    private MyDbContext context = new MyDbContext();

    public void BusinessFunction1()
    {
        // Don't call SaveChanges in here.
    }

    public void BusinessFunction2()
    {
        // Don't call SaveChanges in here.
    }

    public void SaveChanges()
    {
        // All changes made above will automatically be wrapped
        // in a transaction by EF.
        context.SaveChanges();
    }

    public void Dispose()
    {
        context.Dispose();
    }
}

Besides, you already linked to the article that shows you how to do it! I already linked to a couple of articles that shows you the pitfalls of what you want to do.

The problem with what you want to do is that you have to be VERY careful that the transaction mode you use doesn't LOCK THE ENTIRE TABLE while you do your transaction processing. If you're not careful, the lock will prevent other instances from even reading the data in locked tables, preventing other users of your web site from seeing pages that are backed by data!

A guide to posting questions on CodeProject

How to debug small programs

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How to use Multithreading in Async Socket Http request

sbmzhcn27-Apr-14 15:22

sbmzhcn

27-Apr-14 15:22

In multi thread, i use async socket , alway An error occurred：
ReceiveCallback Error: System.ObjectDisposedException: 无法访问已释放的对象。

对象名:“System.Net.Sockets.Socket”。

在 System.Net.Sockets.Socket.EndReceive(IAsyncResult asyncResult, SocketError& errorCode)

在 System.Net.Sockets.Socket.EndReceive(IAsyncResult asyncResult) ....

This is my code:

private void ReceiveCallback(IAsyncResult ar)
        {
            try
            {
                if (null == ar)
                    return;

                // Retrieve the state object and the client socket 
                // from the asynchronous state object.
                StateObject state = (StateObject)ar.AsyncState;
                Socket client = state.workSocket;

                if (null == state)
                    return;

                // Read data from the remote device.
                int bytesRead = client.EndReceive(ar);

                if (bytesRead > 0)
                {
                    //把接收到的数据写入流中
                    ms.Write(state.buffer, 0, bytesRead);
                    state.sb.Append(Encoding.UTF8.GetString(state.buffer, 0, bytesRead));
                    if (!state.sb.ToString().EndsWith("\r\n\r\n"))
                    {
                        client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                            new AsyncCallback(ReceiveCallback), state);
                    }
                    else
                    {
                        int index = state.sb.ToString().IndexOf("\r\n\r\n", System.StringComparison.Ordinal);
                        int lastclr = state.sb.ToString().LastIndexOf("\r\n", index);
                        string strhex = state.sb.ToString().Substring(lastclr + 2, index - lastclr -2);
                        Int32 hex;
                        if (Int32.TryParse(strhex, System.Globalization.NumberStyles.AllowHexSpecifier, null,
                            out hex))
                        {
                            // All the data has arrived; put it in response.
                            if (state.sb.Length > 1)
                            {
                                Response = state.sb.ToString();
                            }
                            // Signal that all bytes have been received.
                            receiveDone.Set();
                        }
                        else
                        {
                            //client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,new AsyncCallback(ReceiveCallback), state);
                            client.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
                            ReceiveCallback, state);
                        }
                    }
                    // Get the rest of the data.
                }
                else
                {
                    // All the data has arrived; put it in response.
                    if (state.sb.Length > 1)
                    {
                        Response = state.sb.ToString();
                    }
                    // Signal that all bytes have been received.
                    receiveDone.Set();
                }
            }
            catch (Exception e)
            {
                throw new Exception("ReceiveCallback Error: " + e);
            }
        }

for (int nIndex = 0; nIndex < value; nIndex++)
                    {
                        // check if thread not created or not suspended
                        if (threadsRun[nIndex] == null && ThreadsRunning)
                        {
                            // create new thread
                            threadsRun[nIndex] = new Thread(new ThreadStart(delegate() { ThreadScraper(); }));
                            // set thread name equal to its index
                            threadsRun[nIndex].Name = nIndex.ToString();
                            // start thread working function
                            threadsRun[nIndex].Start();
                        }
                        else
                        {
                            Console.Write("");
                        }
                    }

looking for a decent book on c# for advanced programmers

Nico Haegens27-Apr-14 1:10

Nico Haegens

27-Apr-14 1:10

I'm looking for a decent book on C# that handles the new features from 4.0 til the latest version of C# in great detail.
Mostly interested in lambda expressions, linq to sql.
So many books out there, but which ones are decent and detailed? Would like a few recommendations.
Many thanks.

Re: looking for a decent book on c# for advanced programmers

Pete O'Hanlon27-Apr-14 1:59

Pete O'Hanlon

27-Apr-14 1:59

Go with Jon Skeet's book. It's very good.

Re: looking for a decent book on c# for advanced programmers

BillWoodruff27-Apr-14 7:08

BillWoodruff

27-Apr-14 7:08

In addition to highly recommending the book by Jon Skeet that Pete O'Hanlon is referring to: "C# In Depth," Third Edition, Manning Press, 2013 [^], I'd highly recommend the "C# Language Fourth Edition," Annotated Edition, Anders Hejlsberg, Mads Torgersen, Scott Wiltamuth, Peter Golde, Addison-Wesley, 2011 [^].

The annotated edition of the C# language reference by Anders, et. al., includes comments (sidebars) by the gurus' gurus of .NET including Jon Skeet, Eric Lippert, Brad Abrams, Jesse Liberty, Joseph Albihari, and Chris Sells, as well as others: imho their comments/discussion are "worth their weight in gold."

I found "CLR via C#," 3rd. Edition, Eric Richter, Microsoft Press, 2010, very informative and well-written, and there is now a 4th. edition of that book out (2012) that I plan to acquire: [^].

“I speak in a poem of the ancient food of heroes: humiliation, unhappiness, discord. Those things are given to us to transform, so that we may make from the miserable circumstances of our lives things that are eternal, or aspire to be so.” Jorge Luis Borges

Re: looking for a decent book on c# for advanced programmers

jschell27-Apr-14 9:36

jschell

27-Apr-14 9:36

I just buy the latest O'Reilly "C# X.X in a nutshell" book. Where X.X would seem to be 5.0 on my shelf right now.

Re: looking for a decent book on c# for advanced programmers

Ravi Bhavnani28-Apr-14 4:44

Ravi Bhavnani

28-Apr-14 4:44