Ejemplos usando el Api de windows para Visual basic

217 - Interceptar los eventos de mouse en un combobox

Ejemplo que crea un Hook para poder capturar algunos eventos de mouse que el control no contempla

Para poder subclasificar el combo, y de esta manera poder capturar algunos de los mensajes referentes al mouse ( Mouse Move, Dobleclic, Clic, mouse down y mouse Up) , pasar como parámetro el Hwnd del combo a la función " Hook_Combo ". Para finalizar el Hook, utilizar la Función Un_Hook también pasando el handle

Colocar en el formulario un control ListBox para agregar los eventos producidos

vista del formulario para mostrar los eventos producidos en el combo

Nota: El formulario se debe llamar Form1 y el ListBox List1 ( o cambiar los nombres en el procedimiento WinProc )

Código fuente en el formulario

' inicia Private Sub Form_Load() Call Hook_Combo(Combo1.hwnd) End Sub ' finaliza Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer) Call UnHook_Combo(Combo1.hwnd) End Sub

Códigofuente en un módulo bas

Option Explicit ' Declaraciones api '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" ( _ ByVal hwnd As Long, _ ByVal nIndex As Long, _ ByVal dwNewLong As Long) As Long Private Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" ( _ ByVal lpPrevWndFunc As Long, _ ByVal hwnd As Long, _ ByVal Msg As Long, _ ByVal wParam As Long, _ ByVal lParam As Long) As Long Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" ( _ ByVal hWnd1 As Long, _ ByVal hWnd2 As Long, _ ByVal lpsz1 As String, _ ByVal lpsz2 As String) As Long ' Constantes para los mensajes del mouse ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' Private Const WM_LBUTTONDBLCLK As Long = &H203 Private Const WM_LBUTTONDOWN As Long = &H201 Private Const WM_LBUTTONUP As Long = &H202 Private Const WM_MBUTTONDBLCLK As Long = &H209 Private Const WM_MBUTTONDOWN As Long = &H207 Private Const WM_MBUTTONUP As Long = &H208 Private Const WM_MOUSEHOVER As Long = &H2A1 Private Const WM_RBUTTONDBLCLK As Long = &H206 Private Const WM_RBUTTONDOWN As Long = &H204 Private Const WM_RBUTTONUP As Long = &H205 Private Const WM_MOUSELEAVE As Long = &H2A3 Private Const WM_MOUSEMOVE As Long = &H200 Dim lpPrevWndProc As Long Public Sub Hook_Combo(Hwnd_Combo As Long) Dim HWND_EDIT As Long ' recupera el hwnd del area de edición del combo HWND_EDIT = FindWindowEx(Hwnd_Combo, 0, "EDIT", vbNullString) ' Inicia el hook lpPrevWndProc = SetWindowLong(HWND_EDIT, -4, AddressOf WinProc) End Sub ' Finaliza el hook Public Sub UnHook_Combo(Hwnd_Combo As Long) Dim HWND_EDIT As Long HWND_EDIT = FindWindowEx(Hwnd_Combo, 0, "EDIT", vbNullString) SetWindowLong HWND_EDIT, -4, lpPrevWndProc End Sub ' Función que intercepta los mensajes de windows para subclasificar el combo ''''''''''''''''''''''''''''''''''''''''''''''''''''' Public Function WinProc(ByVal hwnd As Long, _ ByVal Msg As Long, _ ByVal wParam As Long, _ ByVal lParam As Long) As Long ' Mensajes Select Case Msg Case WM_LBUTTONDBLCLK Form1.List1.AddItem " LEFT BUTTON DBLCLK " Case WM_LBUTTONDOWN Form1.List1.AddItem " LEFT BUTTON DOWN " Case WM_LBUTTONUP Form1.List1.AddItem " LEFT BUTTON UP " Case WM_MBUTTONUP Form1.List1.AddItem " MIDLE BUTTON UP " Case WM_MBUTTONDBLCLK Form1.List1.AddItem " MIDLE BUTTON DBLCLK " Case WM_MBUTTONDOWN Form1.List1.AddItem " MIDLE BUTTON DOWN " Case WM_RBUTTONDBLCLK Form1.List1.AddItem " RIGHT BUTTON DBLCLK" Case WM_RBUTTONDOWN Form1.List1.AddItem " RIGHT BUTTON DOWN " Case WM_RBUTTONUP Form1.List1.AddItem " RIGHT BUTTON UP " 'Case WM_MOUSEMOVE 'Form1.List1.AddItem " MOUSE MOVE " Case Else WinProc = CallWindowProc(lpPrevWndProc, hwnd, Msg, wParam, lParam) End Select End Function

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