[5000]

اكتب هذا الكود كامل
Public Class Form1

    Dim p = -1

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        NextButton.PerformClick()
    End Sub

    Private Sub NextButton_Click(sender As Object, e As EventArgs) Handles NextButton.Click

        If p < 3 Then
            p += 1
            Dim panels = ({Panel1, Panel2, Panel3, Panel4}).ToArray
            For i = 0 To 3
                If i = p Then panels(i).Show() Else panels(i).Hide()
            Next
        End If
    End Sub

    Private Sub PreviousButton_Click(sender As Object, e As EventArgs) Handles PreviousButton.Click
        If p > 0 Then
            p -= 1
            Dim panels = ({Panel1, Panel2, Panel3, Panel4}).ToArray
            For i = 0 To 3
                If i = p Then panels(i).Show() Else panels(i).Hide()
            Next
        End If
    End Sub

End Class