Plus function on vb.net 2005

發問

2008年11月16日 10:26

0

there are txtDisplay, btnOne, btnTwo, btnPlus, btnEqual.

1. Press btnOne, "1" appears on txtDisplay

2. Disappear "1" and Press btnPlus, "+" appears on txtDisplay

3. Disappear "+" and Press btnTwo, "2" appears on txtDisplay

4. Disappear "2" and Press btnEqual, "3" appears on txtDisplay

here is my code:

Code Snippet

Public Class Form1
    Dim MyVariable As String
    Dim total1 As Integer = 0

    Private Sub btnOne_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOne.Click
        txtDisplay.Text = txtDisplay.Text & btnOne.Text
    End Sub

    Private Sub btnTwo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnTwo.Click
        txtDisplay.Text = txtDisplay.Text & btnTwo.Text
    End Sub

Private Sub btnPlus_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPlus.Click
        txtDisplay.Text = ""
        total1 = total1 + Val(txtDisplay.Text)
        txtDisplay.Text = ""
        txtDisplay.Text = total1
    End Sub

    Private Sub btnEqual_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEqual.Click

        txtDisplay.Text = total1

   End Sub

End Class

My question is:

how to handle btnEqual? I can't display the answer "3".
- 回覆
- 引述

所有回覆

2008年11月16日 14:19

0

Your requirements seems to be can't fulfilled by the code you provided:

Code Snippet

Public Class Form1
    Dim MyVariable As String    'This variable will never used
    Dim total1 As Integer = 0

    Private Sub btnOne_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOne.Click
        txtDisplay.Text = txtDisplay.Text & btnOne.Text    'You are appending the Text in the txtDisplay box instead of just showing "1" on the text box
    End Sub

    Private Sub btnTwo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnTwo.Click
        txtDisplay.Text = txtDisplay.Text & btnTwo.Text    'Same as above
    End Sub

Private Sub btnPlus_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPlus.Click
        txtDisplay.Text = ""    'You have cleared the content in the txtDisplay hence the next statement won't have the expected result
        total1 = total1 + Val(txtDisplay.Text)
        txtDisplay.Text = ""
        txtDisplay.Text = total1
    End Sub

    Private Sub btnEqual_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEqual.Click

        txtDisplay.Text = total1

   End Sub

End Class

Try to think about the logic of your program clearly first and then implement each requirement/state listed one by one. I think you should eventually get the result you want.

Sorry that I am not going to provide the complete code for you as again, this seems to be an assignment from school. I am sure that the most important thing to you is to understand how to do programming instead of just completing one assignment. Knowing how to design and complete a program will benefit you more.
- 回覆
- 引述
2008年11月16日 16:17

0

You haven't make use of the variable - MyVariable which is very important to store and sum up the values. Please take a look at this article for reference: http://www.homeandlearn.co.uk/net/nets1p17.html

Regards,

Colt
- 回覆
- 引述
2008年11月18日 9:24

0

Colt, he is using Total1 to store the sum.
- 回覆
- 引述
2008年11月19日 15:36

0

Hi Ken,

total1 is storing a value of an empty string as shown in his code instead:

Private Sub btnPlus_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPlus.Click
txtDisplay.Text = ""
total1 = total1 + Val(txtDisplay.Text)

Regards,

Colt
- 回覆
- 引述