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Summary

The EnumDesktopWindows API

C# Signature:

[DllImport("user32.dll")]
static extern bool EnumDesktopWindows(IntPtr hDesktop,
   EnumDesktopWindowsDelegate lpfn, IntPtr lParam);

User-Defined Types:

None.

Notes:

None.

Tips & Tricks:

Please add some!

Sample Code:

using System;

using System.Text;

using System.Collections;

using System.Runtime.InteropServices;

/// <summary>

/// EnumDesktopWindows Demo - shows the caption of all desktop windows.

/// Authors: Svetlin Nakov, Martin Kulov

/// Bulgarian Association of Software Developers - http://www.devbg.org/en/

/// </summary>

public class EnumDesktopWindowsDemo

{

    const int MAXTITLE = 255;

    private static ArrayList mTitlesList;

    private delegate bool EnumDelegate(IntPtr hWnd, int lParam);

    [DllImport("user32.dll", EntryPoint="EnumDesktopWindows",
     ExactSpelling=false, CharSet=CharSet.Auto, SetLastError=true)]
    private static extern bool _EnumDesktopWindows(IntPtr hDesktop,
    EnumDelegate lpEnumCallbackFunction, IntPtr lParam);

    [DllImport("user32.dll", EntryPoint="GetWindowText",
     ExactSpelling=false, CharSet=CharSet.Auto, SetLastError=true)]
    private static extern int _GetWindowText(IntPtr hWnd,
    StringBuilder lpWindowText, int nMaxCount);

    private static bool EnumWindowsProc(IntPtr hWnd, int lParam)
    {
    string title = GetWindowText(hWnd);
    mTitlesList.Add(title);
    return true;
    }

    /// <summary>
    /// Returns the caption of a windows by given HWND identifier.
    /// </summary>
    public static string GetWindowText(IntPtr hWnd)
    {
    StringBuilder title = new StringBuilder(MAXTITLE);
    int titleLength = _GetWindowText(hWnd, title, title.Capacity + 1);
    title.Length = titleLength;

    return title.ToString();
    }

    /// <summary>
    /// Returns the caption of all desktop windows.
    /// </summary>
    public static string[] GetDesktopWindowsCaptions()
    {
    mTitlesList = new ArrayList();
    EnumDelegate enumfunc = new EnumDelegate(EnumWindowsProc);
    IntPtr hDesktop = IntPtr.Zero; // current desktop
    bool success = _EnumDesktopWindows(hDesktop, enumfunc, IntPtr.Zero);

    if (success)
    {
        // Copy the result to string array
        string[] titles = new string[mTitlesList.Count];
        mTitlesList.CopyTo(titles);
        return titles;
    }
    else
    {
        // Get the last Win32 error code
        int errorCode = Marshal.GetLastWin32Error();

        string errorMessage = String.Format(
        "EnumDesktopWindows failed with code {0}.", errorCode);
        throw new Exception(errorMessage);
    }
    }

    static void Main()
    {
    string[] desktopWindowsCaptions = GetDesktopWindowsCaptions();
    foreach (string caption in desktopWindowsCaptions)
    {
        Console.WriteLine(caption);
    }
    }

}

Alternative Managed API:

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Documentation

EnumDesktopWindows on MSDN