depositing numbers into a textbox and subtracting

Question

 

hi i would like to know how you add and subtract numbers from a text box, i currently have 3 text boxes one which is the balance textbox, and i have a textbox to deposit and withdraw, i want to add numbers to the balance box then be able to take them out again but i cant find the right code to do it. any ideas?

Answer 1

Not sure if I got it right but I'll try!

 

Create a new project.

Put on the left side of the form a ListBox1 and underneath a Textbox1

On the right side of the form add a TextBox2 and a Button1

 

Now switch to CODE VIEW and replace everything in there with the code below!

 

The code does the following:

• Calculates your current balance based on its actual value and what you type in to the TextBox2 when clicked on Button1
• Substracts the double-clicked value in the ListBox1 from your balance and removes the ListBox item afterwards

Warning:

I am beginner, so, this is a very unprofessional code (but functional!)

 

Code Block

Public Class Form1

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

'Set a default balance on program start

Dim balance As Integer

balance = "100"

'TextBox1 to reflect your balance on the form

TextBox1.Text = balance

'TextBox2 to add / substract

TextBox2.Text = "0"

End Sub

 

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

'When button is clicked add the text of TextBox2 to the item List

ListBox1.Items.Add(TextBox2.Text)

'Calculate your balance based on curront balance in TextBox1 + value in TextBox2

Dim result As Integer

Dim x As Double

x = TextBox1.Text

Dim y As Double

y = TextBox2.Text

result = (x + y)

'Update the balance in your TextBox1

TextBox1.Text = result

End Sub

 

Private Sub ListBox1_DoubleClick(ByVal sender As Object, ByVal e As System.EventArgs) Handles ListBox1.DoubleClick

Dim result As Integer

Dim x As Double

x = TextBox1.Text

Dim y As Double

y = ListBox1.SelectedItem

result = (x - y)

'Removing the selected ListBox item:

Dim remove As String

remove = ListBox1.SelectedItem

ListBox1.Items.Remove(remove)

'Updating our total

TextBox1.Text = result

End Sub

End Class

 

 

You can substract from your balance by typing a - in front of the number in TextBox2!

Answer 2

You'll have to convert the value in your textbox to a double

 

Dim val As Double

 

val = Double.Parse(_textbox.Text)

 

After that you can do what ever you want with this value

 

val += 1000

 

And set it back to the text box by converting it to a string again

 

_textbox.Text = val.ToString()