Synchronize two Listviews scroll

[brenaaro]

I have two Listviews side-by-side and I want their scrolling behavior to be synchronized. I.E. When the user drags the vertical scroll bar up or down on one list view, I would like the other listview to do the same.

I have already hooked the two listviews and trapped the WM_VSCROLL messages, which are fine for when the user clicks the "Scroll Up" and "Scroll Down" arrows on the scroll bar. But what messages can I trap to detect when the user drags the scrollbar with the mouse?

Thanks

[tassoma]

Hey,

Did you find a solution for your issue?

I know it is almost 12 years ago!

[Edgemeal]

Seems you need to check the LOWORD of wParam when receiving a Scroll message.
Quick test in VB.Net,....

Public Class ListViewEx
    Inherits ListView

    Private Const SB_THUMBTRACK As Int32 = 5
    Private Const SB_ENDSCROLL As Int32 = 8
    Private Const WM_VSCROLL As Int32 = &H115

    Protected Overrides Sub WndProc(ByRef m As System.Windows.Forms.Message)
        Select Case m.Msg
            Case WM_VSCROLL
                ' see https://msdn.microsoft.com/en-us/library/windows/desktop/bb787577(v=vs.85).aspx
                '
                ' wParam
                ' The LOWORD specifies a scroll bar value that indicates the user's scrolling request. 
                '
                ' get LOWORD from wParam
                Dim lw = LOWORD(m.WParam)
                '  show result
                Select Case lw
                    Case SB_THUMBTRACK
                        Debug.WriteLine("The user is dragging the scroll box. ")
                    Case SB_ENDSCROLL
                        Debug.WriteLine("Ends scroll.")
                End Select
        End Select
        MyBase.WndProc(m)
    End Sub

    ' Converted to VB from NativeMethods.cs,
    ' http://referencesource.microsoft.com/#System.Windows.Forms/winforms/Managed/System/WinForms/NativeMethods.cs,e1ab28ba69954959

    Public Shared Function LOWORD(n As Integer) As Integer
        Return n And &HFFFF
    End Function

    Public Shared Function LOWORD(n As IntPtr) As Integer
        Return LOWORD(CInt(CLng(n)))
    End Function

End Class