Declaring a Variable then Changing it later in a program

Declaring a Variable then Changing it later in a program

• ayeli

  Just figured it out.  The problem was when I redefined Elasticity in the button3 click event it became a temporary variable different than my global variable.  By just not defining it it defaults to the global one and everything works.  An incredibly simple fix man I feel a little stupid right now.
  

• PrashanthSpark

  hi,

  you have two problems in your code

  Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click

  Dim Prompt As String ' the problem was here you have 2 variables have the same name so when you intialize your input box it give the value to the string variable not to the global variable so remove the local variable elasticity

  Prompt = "Please enter the Modulus of Elasticity in ksi."

  Elasticity = Double.Parse(InputBox(Prompt)) 'aslo you can parse the input directly here to double

  Label3.Text = ("Modulus of Elasticity is " & Elasticity & " ksi")

  End Sub

  Private Sub changevariable(ByVal NewElasticity As Double)

  'remove this sub you even didn't call it and you don't have to call it even

  Elasticity = NewElasticity

  End Sub

  hope it was helpfull

  
  
  

• LucyS

  hi,

  if yo use this variable for particular sub   you can call the sub after you change the value

  
  
  

• Eran Kampf

  hi,

  i don't know what you mean for example this is a form has label, textbox, button to call the sub is what you mean something like that

  Public Class Form1

  Private var As Integer = 1

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

  Label1.Text = "hello"

  var = 2

  TextBox1.Text = var

  End Sub

  End Class

  if you read the value of variable from another sub it will change the variable but will not show its value in the form untill you call this sub

  i suggest to make a function or sub and you call it inside your code after your variable value changed like that

  Public Class Form1

  Private var As Integer = 1

  Private Sub changevariable(ByVal newvar As Integer)

  TextBox1.Text = newvar

  End Sub

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

  Label1.Text = "hello"

  var = 2

  changevariable(var)

  End Sub

  End Class

  hope it was helpfull

  
  
  

• Michel

  I appreciate you help on this and I may be missing something simple because i said i'm a complete noob at this.  I couldn't get the code you pasted to work.  Perhaps it would be best for me to show you the code I and explain how I want it to work.

  Public Class Form1

  Dim Elasticity As Double = 29500

  Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click

  Dim Prompt, Elasticity As String

  Prompt = "Please enter the Modulus of Elasticity in ksi."

  Elasticity = InputBox(Prompt)

  Label3.Text = ("Modulus of Elasticity is " & Elasticity & " ksi")

  End Sub

  Private Sub changevariable(ByVal NewElasticity As Double)

  Elasticity = NewElasticity

  End Sub

  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

  MessageBox.Show(Elasticity)

  End Sub

  End Class

  Basically what this form is doing is initally setting Elasticity = 29500 then if Button3 is clicked it asks you for a new elasticity value and inputs that in the Label3.  Then on the button 1 click it pops up with a message box that shows the value of the Elasticity variable.  I need it to take the string value I'm inputting on the button3 click event and convert that to a double and replace the global Elasticity value with the new value I have entered through the Button3 click event.  Is this possible

  
  

• AFuchigami

  Done and Done and its working great, thanks!
  

• Mark Henneman

  you are welcome
  
  

• Liren Zhao

  Exactly, thats what I want to do.  Start off with the variable as a default value then if the user chooses to change it have it changed to his new input and the changed variable will be used by later subroutine.  The problem is that initially I make the default value of the variable globally available, use a subroutine to allow the user to change it (this subroutine also changes a label to match the users input), but then when the subroutine closes yes my labels have changed the but new value is not available globally, its still the default value I had initally declared.
  
• Declaring a Variable then Changing it later in a program