get all controls by FindWindowEx

Question

I am building an applicaton, It will get all control have into application winform is running. First, I can inject dll into application winform is running and get handle of application winform is running. After I get all child window into applcation. Next, I want get all controls into child window by FindWindowEx. But I can't

Here is code :

static ArrayList GetAllChildrenWindowHandles(IntPtr hParent, int maxCount)
    {
        ArrayList result = new ArrayList();
        int ct = 0;
        IntPtr prevChild = IntPtr.Zero;
        IntPtr currChild = IntPtr.Zero;
        while (true && ct < maxCount)
        {
            currChild = FindWindowEx(hParent, prevChild, null, null);
            if (currChild == IntPtr.Zero)
            {
                int errorCode = Marshal.GetLastWin32Error();
                break;
            }
            result.Add(currChild);
            prevChild = currChild;
            ++ct;
        }
        return result;
    }

I get a handle of child window and use it is parent. But I can't get all control into child window by FindWindowEx . Sorry for my english

If you're going to find all the children of some particular window, you want [`EnumChildWindows`](http://msdn.microsoft.com/en-us/library/windows/desktop/ms633494.aspx). — Jerry Coffin, Apr 24 '13 at 15:52
The logical structure is a tree. Most easily traversed with a recursive function. However, that surely also means that an ArrayList is not the proper data structure to store the result. — Hans Passant, Apr 24 '13 at 19:43
"The logical structure is a tree. Most easily traversed with a recursive function. However, that surely also means that an ArrayList is not the proper data structure to store the result" I think too, but I don't know how do this? Do you know? Thank :) — user2208401, Apr 25 '13 at 01:11

score 8 · Answer 1 · edited May 23 '17 at 12:13

You can use the code below. Put it into a helper class somewhere, and e.g. use it like this...

var hwndChild = EnumAllWindows(hwndTarget, childClassName).FirstOrDefault();

You can 'lose' the class check if you wish - but usually you're checking for a specific target.

You may also wanna check this post I made a while go - which is using this method to set a focus on a remote window (and those scenarios are quite common, and you'll hit that snag sooner or later).
Pinvoke SetFocus to a particular control

public delegate bool Win32Callback(IntPtr hwnd, IntPtr lParam);

[DllImport("user32.Dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool EnumChildWindows(IntPtr parentHandle, Win32Callback callback, IntPtr lParam);

[DllImport("user32.dll", CharSet = CharSet.Auto)]
static public extern IntPtr GetClassName(IntPtr hWnd, System.Text.StringBuilder lpClassName, int nMaxCount);

private static bool EnumWindow(IntPtr handle, IntPtr pointer)
{
    GCHandle gch = GCHandle.FromIntPtr(pointer);
    List<IntPtr> list = gch.Target as List<IntPtr>;
    if (list == null)
        throw new InvalidCastException("GCHandle Target could not be cast as List<IntPtr>");
    list.Add(handle);
    return true;
}

public static List<IntPtr> GetChildWindows(IntPtr parent)
{
    List<IntPtr> result = new List<IntPtr>();
    GCHandle listHandle = GCHandle.Alloc(result);
    try
    {
        Win32Callback childProc = new Win32Callback(EnumWindow);
        EnumChildWindows(parent, childProc, GCHandle.ToIntPtr(listHandle));
    }
    finally
    {
        if (listHandle.IsAllocated)
            listHandle.Free();
    }
    return result;
}

public static string GetWinClass(IntPtr hwnd)
{
    if (hwnd == IntPtr.Zero)
        return null;
    StringBuilder classname = new StringBuilder(100);
    IntPtr result = GetClassName(hwnd, classname, classname.Capacity);
    if (result != IntPtr.Zero)
        return classname.ToString();
    return null;
}

public static IEnumerable<IntPtr> EnumAllWindows(IntPtr hwnd, string childClassName)
{
    List<IntPtr> children = GetChildWindows(hwnd);
    if (children == null)
        yield break;
    foreach (IntPtr child in children)
    {
        if (GetWinClass(child) == childClassName)
            yield return child;
        foreach (var childchild in EnumAllWindows(child, childClassName))
            yield return childchild;
    }
}

It's not work, I can get all controls into child windows of application winform running. I only get child windows but can't get all controls into child windows. — user2208401, Apr 25 '13 at 01:13
that works - try Spy++ (or [this](http://mwinapi.sourceforge.net/)) to test - see this exact same code [here](http://stackoverflow.com/questions/7014190/why-is-enumchildwindows-skipping-children) (and make sure you load all, give it time). And try my suggestion from 'SetFocus' link (attach to a 'thread'). If your controls are `non-standard` (non windows) it won't work. And remove the `.FirstOrDefault()` of course :) — NSGaga-mostly-inactive, Apr 25 '13 at 01:50
I am getting error "The type or namespace name 'Win32Callback' could not be found (are you missing a using directive or an assembly reference?)" — Ashish, Mar 18 '14 at 06:20

score 1 · Answer 2 · answered Apr 25 '13 at 10:06

1

Try Spy++ and see the controls you are trying to enumerate are windows or not. If they are not windows, you can not enumerate them using this API.

answered Apr 25 '13 at 10:06

crapple

11
1
3

2

How could a control displayed by Spy++ not be a window? – Werner Henze Apr 25 '13 at 11:11
@WernerHenze: That's the point of using Spy++. The code in the question may fail because the control is not a window, but in that case Spy++ would fail in the same way. I.e. we use Spy++ to establish the correct behavior. – MSalters Apr 25 '13 at 12:27
@MSalters: So you are talking for example about a parent window which is drawing something in it's client area that looks like a control and handling mouse clicks so it acts like a control, but in fact it is not a real window, it just looks like one from user perspective!? – Werner Henze Apr 25 '13 at 12:57
@WernerHenze: Yup, like for example Internet Explorer does. – MSalters Apr 25 '13 at 12:59
3

So - I've used Spy++ and have determined that the text I need to get at isn't a control (or 'Window') in its own right, but I can get its parent window. Is there an API that I can use to somehow query this text anyway!? – Chris Roberts Jan 31 '18 at 15:17

get all controls by FindWindowEx

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