Mini Calculator in VB.NET

Hi all:

I have codes for small calculator in VB.NET and it works just fine.  I setup three textboxes (textbox1 and textbox2 is where user enters values; the textbox3 displays result).  I have two questions:

1.  How can you code for textbox1 and textbox2 only accept numeric values?  If  user not enters numeric value, display   appropriate message to ask entering numeric values.

2.  How can you code not to allow any number devide by zero?


Please see my code below for this app

===================================================================

Dim FirstNum, SecondNum As Double
    Dim MyNumber As String

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        End
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Assign text box values to variables
        FirstNum = TextBox1.Text
        SecondNum = TextBox2.Text      
       
        'Determine checked button and calculate
       
        If RadioButton2.Checked = True Then
            TextBox3.Text = FirstNum - SecondNum
        End If
       
        If RadioButton1.Checked = True Then
            TextBox3.Text = FirstNum + SecondNum
        End If
       
        If RadioButton4.Checked = True Then
            TextBox3.Text = FirstNum / SecondNum
        End If
       
        If RadioButton3.Checked = True Then
            TextBox3.Text = FirstNum * SecondNum
        End If

    End Sub
==============================================

Thanks in advance

Larry
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click        
        TextBox1.Text = Nothing      
        TextBox2.Text = Nothing      
        TextBox3.Text = Nothing        
        TextBox1.Focus()
    End Sub
End Class
larryleAsked:
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

x
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Arthur_WoodCommented:
the divide by zero question is easy:

If RadioButton4.Checked = True Then
      if SecondNum <> 0 then
            TextBox3.Text = FirstNum / SecondNum
      else
            MessageBox.Show("Cannot divide by zero!!!")
      end if
End If


as for the Numeric values only in the textboxes:

1)
    Private Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        If e.KeyChar.IsDigit(e.KeyChar) OrElse Asc(e.KeyChar) = Asc(".") OrElse Asc(e.KeyChar) = 8 Then
           e.Handled = False
        Else
            e.Handled = True
        End If
    End Sub

    Private Sub TextBox2_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        If e.KeyChar.IsDigit(e.KeyChar) OrElse Asc(e.KeyChar) = Asc(".") OrElse Asc(e.KeyChar) = 8 Then
           e.Handled = False
        Else
            e.Handled = True
        End If
    End Sub

the value 8 here is to allow the backspace key, to erase a value.

AW

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
larryleAuthor Commented:
Dear AW:

This program is working beautiful  now and I really much appreciate for your excellent input.

Thanks as always.

Larry
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Visual Basic Classic

From novice to tech pro — start learning today.