CIS206 - Advanced Visual Basic - Week 4

Inheritance and Interfaces 

Review from Week 1 and 3

Code snippets from Week 1

Button toggle logic

Private Sub btnToggle_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnToggle.Click
    If btnToggle.Text = "&Answer" Then
        btnToggle.Text = "&Picture"
        txtAnswer.Visible = True
        picLogo.Visible = False
    Else
        btnToggle.Text = "&Answer"
        txtAnswer.Visible = False
        picLogo.Visible = True
    End If
End Sub

 Radio Button Check Changed logic

Private Sub rdoBears_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles rdoBears.CheckedChanged
        lblTeamName.Text = "Bears"
        picLogo.Image = picBears.Image
End Sub

Bold / Italic (Style) change logic

Private Sub chkItalic_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles chkItalic.CheckedChanged
    Dim myStyle As New FontStyle()

    myStyle = lblTeamName.Font.Style
    myStyle = IIf(chkItalic.CheckState = CheckState.Checked, myStyle Or FontStyle.Italic, myStyle And Not FontStyle.Italic)

    Dim myFont As New Font(lblTeamName.Font, myStyle)

    lblTeamName.Font = myFont
    txtAnswer.Font = myFont

End Sub

Font Size change logic

Private Sub nudSize_ValueChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles nudSize.ValueChanged
    Dim myFont As New Font(lblTeamName.Font.FontFamily, nudSize.Value, lblTeamName.Font.Style)
    lblTeamName.Font = myFont
    txtAnswer.Font = myFont
End Sub

Form Load to initialize user interface

Private Sub frmMain_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
    rdoBears.Checked = True
    txtAnswer.Text = "No, the images loaded into controls at design time " & _
                                "are stored in a project resource file, and compiled " & _
                                    "into the executable"
End Sub

 

Source from Week 3

Download the project

Example 1

Inheritance Example

This example extends the tax calculation project from last week by creating tax objects for individual states. Each state class inherits from the base tax class overriding the calculations as is necessary.

Download the example

Example 2

Interface Example

A base class implements an interface and can not be instantiated directly. Three classes that inherit from the base also inherit the interface.   

Download the example

Assignment

Build a series of classes that inherit from a base class and implement two methods for each. Review the examples and use the shell as a starting point. You may enhance in any way that you would like, or simply implement the methods as required by the base class.

Download the zipped .EXE

Download the source shell      

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