免责声明：仅仅因为我们可以，并不意味着我们应该！
此示例专门设计用于使用ColorDialoginFullOpen模式。它依赖于这样一个事实：Edit对话框中的“红色：”、“绿色：”和“蓝色：”控件会随着用户更改颜色而实时更新，并且WM_CTLCOLOREDIT每次这些控件都会发送a控件被更新（这也适用于手动输入这些值时）。我们必须在MyColorDialog每次要使用它时创建一个新实例，以便这些控件的窗口句柄是正确的。
下面的WindowsEnumerator课程基于 Bob (TheLearnedOne) 的工作。
*我Idle_Mind也在专家交流中心。
这是在 VS2010 Premium 的 Win8 Pro 上测试的。如果需要对其他版本的 Windows 中的 ColorDialog 进行任何更改，我不需要：
Public Class Form1
Private WithEvents PicBox As New PictureBox
Private WithEvents ColorDlg As MyColorDialog = Nothing
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
PicBox.BackColor = Color.Blue
Me.Controls.Add(PicBox)
End Sub
Private Sub PicBox_Click(sender As Object, e As EventArgs) Handles PicBox.Click
ColorDlg = New MyColorDialog
ColorDlg.Color = sender.backcolor
If ColorDlg.ShowDialog() = Windows.Forms.DialogResult.OK Then
sender.BackColor = ColorDlg.Color
End If
ColorDlg = Nothing
End Sub
Private Sub ColorDlg_CurrentColor(c As System.Drawing.Color) Handles ColorDlg.CurrentColor
PicBox.BackColor = c
End Sub
End Class
Public Class MyColorDialog
Inherits ColorDialog
Public Event CurrentColor(ByVal c As Color)
Private Const GA_ROOT As Integer = 2
Private Const WM_CTLCOLOREDIT As Integer = &H133
Public Declare Function GetAncestor Lib "user32.dll" _
(ByVal hWnd As IntPtr, ByVal gaFlags As Integer) As IntPtr
Private EditWindows As List(Of ApiWindow) = Nothing
Public Sub New()
Me.FullOpen = True
End Sub
<System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
Protected Overrides Function HookProc(ByVal hWnd As IntPtr, ByVal msg As Integer, ByVal wParam As IntPtr, ByVal lParam As IntPtr) As IntPtr
Select Case msg
Case WM_CTLCOLOREDIT
If IsNothing(EditWindows) Then
Dim mainWindow As IntPtr = GetAncestor(hWnd, GA_ROOT)
If Not mainWindow.Equals(IntPtr.Zero) Then
EditWindows = New List(Of ApiWindow)((New WindowsEnumerator).GetChildWindows(mainWindow, "Edit"))
End If
End If
If Not IsNothing(EditWindows) AndAlso EditWindows.Count = 6 Then
Dim strRed As String = WindowsEnumerator.WindowText(EditWindows(3).hWnd)
Dim strGreen As String = WindowsEnumerator.WindowText(EditWindows(4).hWnd)
Dim strBlue As String = WindowsEnumerator.WindowText(EditWindows(5).hWnd)
Dim Red, Green, Blue As Integer
If Integer.TryParse(strRed, Red) Then
If Integer.TryParse(strGreen, Green) Then
If Integer.TryParse(strBlue, Blue) Then
RaiseEvent CurrentColor(Color.FromArgb(Red, Green, Blue))
End If
End If
End If
End If
End Select
Return MyBase.HookProc(hWnd, msg, wParam, lParam)
End Function
End Class
Public Class ApiWindow
Public hWnd As IntPtr
Public ClassName As String
Public MainWindowTitle As String
End Class
Public Class WindowsEnumerator
Private Delegate Function EnumCallBackDelegate(ByVal hwnd As IntPtr, ByVal lParam As Integer) As Integer
Private Declare Function EnumWindows Lib "user32" _
(ByVal lpEnumFunc As EnumCallBackDelegate, ByVal lParam As Integer) As Integer
Private Declare Function EnumChildWindows Lib "user32" _
(ByVal hWndParent As IntPtr, ByVal lpEnumFunc As EnumCallBackDelegate, ByVal lParam As Integer) As Integer
Private Declare Function GetClassName Lib "user32" Alias "GetClassNameA" _
(ByVal hwnd As IntPtr, ByVal lpClassName As System.Text.StringBuilder, ByVal nMaxCount As Integer) As Integer
Private Declare Function IsWindowVisible Lib "user32" (ByVal hwnd As IntPtr) As Integer
Private Declare Function GetParent Lib "user32" (ByVal hwnd As IntPtr) As Integer
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As IntPtr, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As IntPtr, ByVal wMsg As Integer, ByVal wParam As Integer, ByVal lParam As System.Text.StringBuilder) As Integer
Private _listChildren As New List(Of ApiWindow)
Private _listTopLevel As New List(Of ApiWindow)
Private _topLevelClass As String = String.Empty
Private _childClass As String = String.Empty
Public Overloads Function GetTopLevelWindows() As ApiWindow()
EnumWindows(AddressOf EnumWindowProc, &H0)
Return _listTopLevel.ToArray
End Function
Public Overloads Function GetTopLevelWindows(ByVal className As String) As ApiWindow()
_topLevelClass = className
Return Me.GetTopLevelWindows()
End Function
Public Overloads Function GetChildWindows(ByVal hwnd As Int32) As ApiWindow()
_listChildren.Clear()
EnumChildWindows(hwnd, AddressOf EnumChildWindowProc, &H0)
Return _listChildren.ToArray
End Function
Public Overloads Function GetChildWindows(ByVal hwnd As Int32, ByVal childClass As String) As ApiWindow()
_childClass = childClass
Return Me.GetChildWindows(hwnd)
End Function
Private Function EnumWindowProc(ByVal hwnd As Int32, ByVal lParam As Int32) As Int32
If GetParent(hwnd) = 0 AndAlso IsWindowVisible(hwnd) Then
Dim window As ApiWindow = GetWindowIdentification(hwnd)
If _topLevelClass.Length = 0 OrElse window.ClassName.ToLower() = _topLevelClass.ToLower() Then
_listTopLevel.Add(window)
End If
End If
Return 1
End Function
Private Function EnumChildWindowProc(ByVal hwnd As Int32, ByVal lParam As Int32) As Int32
Dim window As ApiWindow = GetWindowIdentification(hwnd)
If _childClass.Length = 0 OrElse window.ClassName.ToLower() = _childClass.ToLower() Then
_listChildren.Add(window)
End If
Return 1
End Function
Private Function GetWindowIdentification(ByVal hwnd As Integer) As ApiWindow
Dim classBuilder As New System.Text.StringBuilder(64)
GetClassName(hwnd, classBuilder, 64)
Dim window As New ApiWindow
window.ClassName = classBuilder.ToString()
window.MainWindowTitle = WindowText(hwnd)
window.hWnd = hwnd
Return window
End Function
Public Shared Function WindowText(ByVal hwnd As IntPtr) As String
Const W_GETTEXT As Integer = &HD
Const W_GETTEXTLENGTH As Integer = &HE
Dim SB As New System.Text.StringBuilder
Dim length As Integer = SendMessage(hwnd, W_GETTEXTLENGTH, 0, 0)
If length > 0 Then
SB = New System.Text.StringBuilder(length + 1)
SendMessage(hwnd, W_GETTEXT, SB.Capacity, SB)
End If
Return SB.ToString
End Function
End Class
