Professor Joy: CMSC222 Class Work

Class Work Week 11

Scroll bars

The first example has two scroll bars each calls calculate.

Public Class Form1

    Private Sub ScrCost_Scroll(ByVal sender As System.Object, ByVal e As
System.Windows.Forms.ScrollEventArgs) Handles ScrCost.Scroll
        LblCost.Text = FormatCurrency(ScrCost.Value / 100)
        Calculate()
    End Sub

    Private Sub ScrRate_Scroll(ByVal sender As System.Object, ByVal e As _ 
          System.Windows.Forms.ScrollEventArgs) Handles ScrRate.Scroll
        LblRate.Text = ScrRate.Value
        Calculate()
    End Sub
    Private Sub Calculate()
        Dim Cost As Double = ScrCost.Value / 100
        Dim Rate As Integer = ScrRate.Value
        Dim Result As Double = Cost * Rate / 100
        LblResult.Text = FormatCurrency(Result)
    End Sub
End Class

The second example uses global variables:

Public Class Form1
    Dim Cost As Double
    Dim Rate As Integer
    Private Sub ScrCost_Scroll(ByVal sender As System.Object, ByVal e As
System.Windows.Forms.ScrollEventArgs) Handles ScrCost.Scroll
        Cost = ScrCost.Value / 100
        LblCost.Text = FormatCurrency(Cost)
        Calculate()
    End Sub

    Private Sub ScrRate_Scroll(ByVal sender As System.Object, ByVal e As
System.Windows.Forms.ScrollEventArgs) Handles ScrRate.Scroll
        Rate = ScrRate.Value
        LblRate.Text = ScrRate.Value
        Calculate()
    End Sub
    Private Sub Calculate()
        Dim Result As Double = Cost * Rate / 100
        LblResult.Text = FormatCurrency(Result)
    End Sub
End Class

The third example lets one sub handle both scroll bars:

Public Class Form1

    Private Sub Calculate(ByVal sender As System.Object, ByVal e As
System.Windows.Forms.ScrollEventArgs) Handles ScrCost.Scroll, ScrRate.Scroll
        Dim Cost As Double = ScrCost.Value / 100
        Dim Rate As Integer = ScrRate.Value
        LblCost.Text = FormatCurrency(Cost)
        LblRate.Text = ScrRate.Value
        Dim Result As Double = Cost * Rate / 100
        LblResult.Text = FormatCurrency(Result)
    End Sub
End Class

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