EnumChildWindows Function

The EnumChildWindows function enumerates the child windows that belong to the specified parent window by passing the handle to each child window, in turn, to an application-defined callback function. EnumChildWindows continues until the last child window is enumerated or the callback function returns FALSE.

Syntax

BOOL EnumChildWindows(      
    HWND hWndParent,
    WNDENUMPROC lpEnumFunc,
    LPARAM lParam
);

Parameters

hWndParent
[in] Handle to the parent window whose child windows are to be enumerated. If this parameter is NULL, this function is equivalent to EnumWindows.

Windows 95/98/Me: hWndParent cannot be NULL.

lpEnumFunc
[in] Pointer to an application-defined callback function. For more information, see EnumChildProc.
lParam
[in] Specifies an application-defined value to be passed to the callback function.

Return Value

Not used.

Remarks

If a child window has created child windows of its own, EnumChildWindows enumerates those windows as well.

A child window that is moved or repositioned in the Z order during the enumeration process will be properly enumerated. The function does not enumerate a child window that is destroyed before being enumerated or that is created during the enumeration process.

Example

For an example see Destroying a Window.

Function Information

Minimum DLL Versionuser32.dll
HeaderDeclared in Winuser.h, include Windows.h
Import libraryUser32.lib
Minimum operating systems Windows 95, Windows NT 3.1
UnicodeImplemented as Unicode version.

See Also

Tags :


Community Content

Noelle Mallory - MSFT
Possible VB9 declaration
Friend Declare Function EnumChildWindows Lib "user32.dll" (ByVal hWndParent As Int32, ByVal lpEnumFunc As EnumWindowsProc, ByVal lParam As Int32) As Boolean

Example: (this example is part of class that represents Win32 native window)
        ''' <summary>Adds <paramref name="item"/> to <paramref name="List"/> and returns true</summary>
        ''' <param name="List"><see cref="List(Of T)"/> to add item to</param>
        ''' <param name="item">Item to be added</param>
        ''' <typeparam name="T">Type of <paramref name="item"/></typeparam>
        ''' <returns>True</returns>
        Private Shared Function AddToList(Of T)(ByVal List As List(Of T), ByVal item As T) As Boolean
            List.Add(item)
            Return True
        End Function
        ''' <summary>Gets all childrens of current windows</summary>
        ''' <returns>Childrens of current window</returns>
        ''' <exception cref="API.Win32APIException">Error while enumerating windows. Ie. <see cref="Handle"/> is invalid</exception>
        <Category("Relationship")> _
        <TypeConverter(GetType(CollectionConverter))> _
        Public ReadOnly Property Children() As IReadOnlyList(Of Win32Window) 'Localize: description
            Get
                Dim List As New List(Of Win32Window)
                If API.EnumChildWindows(hWnd, New API.EnumWindowsProc(Function(hWnd As Integer, lParam As Integer) AddToList(List, New Win32Window(hWnd))), 0) Then
                    Return New ReadOnlyListAdapter(Of Win32Window)(List)
                Else
                    Dim ex As New API.Win32APIException
                    If ex.NativeErrorCode <> 0 Then
                        Throw ex
                    Else
                        Return New ReadOnlyListAdapter(Of Win32Window)(List)
                    End If
                End If
            End Get
        End Property
Tags :

Thomas Lee
Empty "Return Value" section
The section "Return Value" does not say anything about the expected return values and their meaning.
Tags : contentbug

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