vb6 conversion program problem

hi first of all i would like to state i am currently at college, ive been trying to get the isNumeric function to work with my Euro to pounds conversion. i can get it to work with my pounds to euro conversion, but even when i try to input numbers into the field when i have the euro to pounds option selected it says "please enter a valid number" (the message i have inputed when a user trys to input anything other than a number). heres my code, any help is much appreciated.

Code:

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Option Explicit
Dim euroToSterlingRate As Currency 'declares the variable "euroToSterlingRate" as currency
Dim sterlingToEuroRate As Currency 'declares the variable "sterlingToEuroRate" as currency
Private Sub cmdChangeEuroToPoundRate_Click()
Dim EuroToPoundanswer As String 'declares the variable "EuroToPOundanswer as a string
'when the user presses the button a input box apears.
'when the user inputs a number into this input box and presses "ok",
'it changes the euro to pound conversion rate to the entered amount.
EuroToPoundanswer = InputBox("Enter the current Euro to pound coversion rate:")
If EuroToPoundanswer <> "" Then
 euroToSterlingRate = EuroToPoundanswer
 End If
End Sub
Private Sub cmdChangePoundToEuroRate_Click()
Dim answer As String 'declares the variable "answer" as a string
'when the user presses the button a input box apears.
'when the user inputs a number into this input box and presses "ok",
'it changes the pound to euro conversion rate to the entered amou  nt.
answer = InputBox("Enter the current Pound to Euro conversion Rate: ")
If answer <> "" Then
    sterlingToEuroRate = answer
End If
End Sub

Private Sub cmdClear_Click()
'when the user clicks this button the "txtConversionAmount" field is cleared
txtConversionAmount = ""
End Sub

Private Sub cmdConvert_Click()
'this button starts the conversion and displays the answer in a message box

If optPoundsToEuro.Value = True Then 'begins the if stament
 Dim ConvertAmount As Single 'declares the variable "ConvertAmount" as single
 Dim PoundtoEuroAnswer 'this declares the variable "PoundToEuroAnswer"
 Dim userInput As String 'defines the variable "userInput" as string
 userInput = txtConversionAmount.Text
 If IsNumeric(userInput) Then
 ConvertAmount = txtConversionAmount 'declares that the variable ConvertAmount=txtConversionAmount
  'declares that the variable "PoundToEuroAnswer",
 '="ConvertAmount" Multiplied by "sterlingToEuroRate".
 PoundtoEuroAnswer = ConvertAmount * sterlingToEuroRate
 'displays the answer of the amount converted into euros,
 'followed by the word "euros".
  MsgBox (PoundtoEuroAnswer & " euros")
Else
MsgBox ("please enter a valid number")
End If 'ends the if statemant
End If


If optEurosToPounds.Value = True Then
 Dim EuroToPoundanswer 'this delcares the variable "EuroToPoundAnswer"
 '="ConvertAmount" Multiplied by "eurotoSterlingRate"
 If IsNumeric(userInput) Then
 EuroToPoundanswer = ConvertAmount * euroToSterlingRate
 MsgBox (EuroToPoundanswer & " pounds")
Else
MsgBox ("please enter a valid number")
End If
End If
End Sub

Private Sub cmdEuroToPoundCurrentRate_Click()
'this button displays the current Euro to pound conversion rate in a message box
MsgBox ("The Current Euro to Pound Conversion rate is: " & euroToSterlingRate)
End Sub

Private Sub cmdExit_Click()
'this button ends the program
End
End Sub

Private Sub cmdPoundToEuroCurrentRate_Click()
'this button displays the current pound to euro conversion rate in a message box
MsgBox ("The Current Pound to Euro Conversion Rate is " & sterlingToEuroRate)
End Sub
Private Sub Form_Load()
euroToSterlingRate = 2.7 'default value
sterlingToEuroRate = 4.9 'default value
End Sub

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Try stepping through the code 'F8'. I think you will see where the problem is!

I believe your problem is that you define USERINPUT on a condition - Variables should be defined at athe top od the procedure (1st thing that happens)

Code:

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Private Sub cmdConvert_Click()
'this button starts the conversion and displays the answer in a message box

If optPoundsToEuro.Value = True Then 'begins the if stament
 Dim ConvertAmount As Single 'declares the variable "ConvertAmount" as single
 Dim PoundtoEuroAnswer 'this declares the variable "PoundToEuroAnswer"
 Dim userInput As String 'defines the variable "userInput" as string
 userInput = txtConversionAmount.Text
 If IsNumeric(userInput) Then
 ConvertAmount = txtConversionAmount 'declares that the variable ConvertAmount=txtConversionAmount
  'declares that the variable "PoundToEuroAnswer",
 '="ConvertAmount" Multiplied by "sterlingToEuroRate".
 PoundtoEuroAnswer = ConvertAmount * sterlingToEuroRate
 'displays the answer of the amount converted into euros,
 'followed by the word "euros".
  MsgBox (PoundtoEuroAnswer & " euros")
Else
MsgBox ("please enter a valid number")
End If 'ends the if statemant
End If

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This means that if the condition is not met then USERINPUT is NOT DEFINED !

Consequently things wont work as you expect

In addition, a definition like

Code:

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Dim PoundtoEuroAnswer

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Is leading to problems- you defined a variant - which means it can be anything

Why dont you either -

Take all the DIM Statements out of the body and place them at the top of each Procedure (SUB)

or

Please them all at the top of your program as

Option Explicit '(At the very top to make sure you define all your variables)

Private USERINPUT as STRING
Private ConvertAmount As Single
etc

I am sure you have seen other people's programs - you have just messed up on the placement of your Variable definitions

If this doesnt make sense then download any number of programs from www.PlanetSourceCode.com and have a look