Visual Basic 2012 Lesson 17- Using Check Box

[Lesson 16] << [CONTENTS] >> [Lesson 18]

The Check Box

Check box is a control in Visual Basic 2012 that allows the user to select one or more items. For example, in the Font dialog box of any Microsoft Text editor like Microsoft Words, there are many check boxes under the Effects section such as that shown in the figure below. The user can choose underline, subscript, small caps, superscript, blink and more. In Visual Basic 2012, you may create a shopping cart where the user can click on check boxes that correspond to the items they intend to purchase, and the total payment can be calculated simultaneously, as shown in Example 17.1.


Visual Basic 2012

Example 17.1:Shopping Cart


The program code for shopping cart is as follows:

Private Sub BtnCalculate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnCalculate.Click
Const LX As Integer = 100
Const BN As Integer = 500
Const SD As Integer = 200
Const HD As Integer = 80
Const HM As Integer = 300
Const AM As Integer = 150
Dim sum As Integer

If CheckBox1.Checked = True Then
sum += LX
End If

If CheckBox2.Checked = True Then
sum += BN
End If

If CheckBox3.Checked = True Then
sum += SD
End If
If CheckBox4.Checked = True Then
sum += HD
End If

If CheckBox5.Checked = True Then
sum += HM
End If

If CheckBox6.Checked = True Then
sum += AM
End If
Label5.Text = sum.ToString(“c”)

Here is another example

Example 17.2

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Const large As Integer = 10.0
Const medium As Integer = 8
Const small As Integer = 5
Dim sum As Integer

If CheckBox1.Checked = True Then
sum += large
End If

If CheckBox2.Checked = True Then
sum += medium
End If

If CheckBox3.Checked = True Then
sum += small
End If
Label5.Text = sum.ToString(“c”)

Example 17.3

In this example, the user can enter text into a text box and format the font using the three check boxes that represent bold, italic and underline.


The code is as follow:

Private Sub CheckBox1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged
If CheckBox1.Checked Then
TextBox1.Font = New Font(TextBox1.Font, TextBox1.Font.Style Or FontStyle.Bold)
Else
TextBox1.Font = New Font(TextBox1.Font, TextBox1.Font.Style And Not FontStyle.Bold)

End If
End Sub

Private Sub CheckBox2_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox2.CheckedChanged
If CheckBox2.Checked Then
TextBox1.Font = New Font(TextBox1.Font, TextBox1.Font.Style Or FontStyle.Italic)
Else
TextBox1.Font = New Font(TextBox1.Font, TextBox1.Font.Style And Not FontStyle.Italic)

End If
End Sub

Private Sub CheckBox3_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CheckBox3.CheckedChanged
If CheckBox2.Checked Then
TextBox1.Font = New Font(TextBox1.Font, TextBox1.Font.Style Or FontStyle.Underline)
Else
TextBox1.Font = New Font(TextBox1.Font, TextBox1.Font.Style And Not FontStyle.Underline)

End If
End Sub

* The above program uses the CheckedChanged event to respond to the user selection by checking a particular check box, it is similar to the click event. The statement

TextBox1.Font = New Font(TextBox1.Font, TextBox1.Font.Style Or FontStyle.Italic)

will retain the original font type but change it to italic font style.

TextBox1.Font = New Font(TextBox1.Font, TextBox1.Font.Style And Not FontStyle.Italic)

will also retain the original font type but change it to regular font style. (The other statements employ the same logic)


* Instead of “General date”, you can also use the abbreviated format “G” , i.e. Format (Now, “G”). And for “Long Time”, you can use the abbreviated format “T”. As for “Short Time”, you may use the abbreviated format “t”

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