Ejemplos usando el Api de windows para Visual basic

252 - Subclasificar ColumnHeader de un ListView

Subclasificar un ListView para interceptar el MouseMove en un Column Header

Este ejemplo del sitio http://www.10tec.com/home/index.aspx , puede ser útil si se desea mostrar un tip de información , mostrar un texto en una barra de estado etc.., al pasar el puntero del mouse sobre los encabezados

Para poder iniciar el Hook al encabezado, se captura el Hwnd del mismo , con la función FindWindowEx, pasándole el Classname : " msvb_lib_header "

Controles

un Control ListView1

Código fuente en un form con

Option Explicit ' handle Dim m_HdrHwnd As Long Private Sub Form_Load() ' le pasa el HWND ListView , para obtener el Hwnd del Header m_HdrHwnd = FindWindowEx(ListView1.hwnd, 0, "msvb_lib_header", vbNullString) ' instala el Hook Call Hook_ListView(m_HdrHwnd) End Sub Private Sub Form_Unload(Cancel As Integer) ' quita el Hook Call UnHook_ListView(m_HdrHwnd) End Sub

Código en un .bas

Option Explicit ' Declaración de constantes '''''''''''''''''''''''''''' Private Const GWL_WNDPROC = -4 Private Const WM_MOUSEMOVE = &H200 Private Const HDM_FIRST = &H1200 Private Const HDM_HITTEST = HDM_FIRST + 6 Private Const HDM_GETITEMA = (HDM_FIRST + 3) Private Const HDM_GETITEM = HDM_GETITEMA ' Declaraciones Api ''''''''''''''''''''''''''''' Public 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 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 SendMessage Lib "user32" Alias "SendMessageA" ( _ ByVal hwnd As Long, _ ByVal wMsg As Long, _ ByVal wParam As Long, _ lParam As Any) As Long Public Declare Function FindWindowEx Lib "user32" Alias _ "FindWindowExA" ( _ ByVal hWndParent As Long, _ ByVal hwndChildAfter As Long, _ ByVal lpszClass As String, _ ByVal lpszWindow As String) As Long ' estructuras ''''''''''''''''''''''''''''''' Private Type POINTAPI x As Long y As Long End Type Private Type HDHITTESTINFO pt As POINTAPI flags As Long iItem As Long End Type Private Type HD_ITEM mask As Long cxy As Long pszText As String hbm As Long cchTextMax As Long fmt As Long lParam As Long iImage As Long iOrder As Long End Type Private Const HDI_LPARAM = &H8 Private Type TLoHiLong Lo As Integer Hi As Integer End Type Private Type TAllLong All As Long End Type Dim mLH As TLoHiLong, mAL As TAllLong Private m_lPrevWndProc As Long Private Indice As Long Public Sub Hook_ListView(ByVal Handle As Long) m_lPrevWndProc = SetWindowLong(Handle, GWL_WNDPROC, AddressOf WindowProc) Indice = -1 End Sub Public Sub UnHook_ListView(ByVal Handle As Long) SetWindowLong Handle, GWL_WNDPROC, m_lPrevWndProc End Sub Function WindowProc(ByVal hwnd As Long, _ ByVal Mensaje As Long, _ ByVal wParam As Long, _ ByVal lParam As Long) As Long Dim hti As HDHITTESTINFO ' mensaje cuando se hace MouseMove en la cabecera If Mensaje = WM_MOUSEMOVE Then mAL.All = lParam LSet mLH = mAL hti.pt.x = mLH.Lo hti.pt.y = mLH.Hi ' Devuelve en hti, el índice del Column header a partir de _ la posición del mouse SendMessage hwnd, HDM_HITTEST, 0&, hti If hti.iItem <> Indice Then Indice = hti.iItem ' index del Header Form1.Caption = "" If Indice <> -1 Then ' muestra el caption de esta columna Form1.Caption = Form1.ListView1.ColumnHeaders(Indice + 1).Text End If End If End If WindowProc = CallWindowProc(m_lPrevWndProc, hwnd, Mensaje, wParam, lParam) End Function

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ListView - Ejemplos

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