hello
what is the code of if scroll bar of listbox move i

somethins like this ?

if listbox1.scrollmove then 
textbox.text=""
end if

See if this helps.

Public Class Form1
    Private WithEvents tmr As New Timer With {.Enabled = True} '// dynamic.Timer.

    Private Sub tmr_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles tmr.Tick
        Me.Text = ListBox1.TopIndex '// display the top visible item's Index.
    End Sub
End Class

Add a new class into your project and paste this code:

Imports System.Windows.Forms

Public Class BetterListBox
	Inherits ListBox
	' Event declaration
	Public Delegate Sub BetterListBoxScrollDelegate(Sender As Object, e As BetterListBoxScrollArgs)
	Public Event Scroll As BetterListBoxScrollDelegate
	' WM_VSCROLL message constants
	Private Const WM_VSCROLL As Integer = &H115
	Private Const SB_THUMBTRACK As Integer = 5
	Private Const SB_ENDSCROLL As Integer = 8

	Protected Overrides Sub WndProc(ByRef m As Message)
		' Trap the WM_VSCROLL message to generate the Scroll event
		MyBase.WndProc(m)
		If m.Msg = WM_VSCROLL Then
			Dim nfy As Integer = m.WParam.ToInt32() And &Hffff
			If Scroll IsNot Nothing AndAlso (nfy = SB_THUMBTRACK OrElse nfy = SB_ENDSCROLL) Then
				RaiseEvent Scroll(Me, New BetterListBoxScrollArgs(Me.TopIndex, nfy = SB_THUMBTRACK))
			End If
		End If
	End Sub
	Public Class BetterListBoxScrollArgs
		' Scroll event argument
		Private mTop As Integer
		Private mTracking As Boolean
		Public Sub New(top As Integer, tracking As Boolean)
			mTop = top
			mTracking = tracking
		End Sub
		Public ReadOnly Property Top() As Integer
			Get
				Return mTop
			End Get
		End Property
		Public ReadOnly Property Tracking() As Boolean
			Get
				Return mTracking
			End Get
		End Property
	End Class
End Class

Build your project, then drop a BetterListBox from the top of your toolbox onto your form. Add several items, enough to get a scrollbar. Write a handler for the new Scroll event, something like this:

Private Sub betterListBox1_Scroll(Sender As Object, e As BetterListBox.BetterListBoxScrollArgs)
	Console.WriteLine("Scroll to {0}, tracking={1}", e.Top, e.Tracking)
End Sub

The e.Top property tells you which item is now displayed at the top of the ListBox. e.Tracking is true when the user is dragging the thumb. Note that you'll get at least two Scroll events when the user is dragging, one with e.Tracking = true and another with e.Tracking = false when the user releases the thumb.

OR:
You'll have to add support to the ListView class so you can be notified about scroll events. Add a new class to your project and paste the code below. Compile. Drop the new listview control from the top of the toolbox onto your form. Implement a handler for the new Scroll event.

Imports System.Windows.Forms

Class MyListView
	Inherits ListView
	Public Event Scroll As ScrollEventHandler
	Protected Overridable Sub OnScroll(e As ScrollEventArgs)
		Dim handler As ScrollEventHandler = Me.Scroll
		RaiseEvent handler(Me, e)
	End Sub
	Protected Overrides Sub WndProc(ByRef m As Message)
		MyBase.WndProc(m)
		If m.Msg = &H115 Then
			' Trap WM_VSCROLL
			OnScroll(New ScrollEventArgs(CType(m.WParam.ToInt32() And &Hffff, ScrollEventType), 0))
		End If
	End Sub
End Class

Beware that the scroll position (ScrollEventArgs.NewValue) isn't meaningful, it depends on the number of items in the ListView. I forced it to 0. Following your requirements, you want to watch for the ScrollEventType.EndScroll notification to know when the user stopped scrolling. Anything else helps you detect that the user started scrolling. For example:

Private mLastScroll As ScrollEventType = ScrollEventType.EndScroll

Private Sub myListView1_Scroll(sender As Object, e As ScrollEventArgs)
	If e.Type = ScrollEventType.EndScroll Then
		scrollEnded()
	ElseIf mLastScroll <> ScrollEventType.EndScroll Then
		scrollStarted()
	End If
	mLastScroll = e.Type
End Sub
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