Trap for Young (and Old) Players - (Text Box Formatting Trap)

I cant believe I have never come across this problem before (Its now about 14 years working with VB6 on a daily basis)

I tested software on my machine - worked well !
Ran on the customer machine and kept getting strange results

Finally tracked it to this statement

Code:

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ValIncTax = Val(txtInvValue.text)

ValIncTax is a Currency Type
txtInvValue.text is a Text Box

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Here is the problem

The Text Box had the value formatted as ##,###,##0.00
eg, 3,245.65

What was being transferred to ValIncTax was just the 3 ! (The rest was truncated off)
Worked on my machine because I was using figures no larger than 999.99


So there's one for the books !

If you had to PRINT the result, it would need a special FORMAT, and you can easily test values that way. Printing a receipt required TWO DECIMAL PLACES extra. Can now create a MAX SIZE, and MAX VALUES to test. Hasn't failed in 14 years. Never went over $1,000 per unit, though. Can do $100K

Yeah Val() only works on numerics the comma kills it. Would get the same result if it were the letter x where the comma is.

The Val function stops reading the string at the first character it cannot recognize as part of a number. Symbols and characters that are often considered parts of numeric values, such as dollar signs and commas, are not recognized.

Wait till you put it on a system where the region settings are set to use '.' as the thousand separator and ',' as the decimal.....

i'v found it better to accept the input straight as an unformatted number, Save/store it, then show the formatted values when edit is done.. (Gotfocus and lostfocus events are the best....)

Or
You could use the right function to convert string to numeric
CCUR CDBL CSNG CLNG CINT

Code:

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If IsNumeric(txtInvValue.Text) Then
    ValIncTax = CCur(txtInvValue.text)
End If

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The problem you can run into when using CCur() on a Textbox is if the user enters a non-numeric value. Testing the string first can avoid this however. Formatting the contents of the Textbox afterward (as GremlinSA mentioned) can be helpful in some applications, and it can help "train" the user to enter proper values.

Code:

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If IsNumeric(Text1.Text) Then
  Text1.Text = Format$(Text1.Text, "##,###,##0.00")
End If

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This is a sample of my tried and trusted method..

Create a new form .. add two textbox's (simply so that you got two items to transfer focus) then add this code...

Code:

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Public Text1Val

Private Sub Text1_GotFocus()
    Text1.Text = Text1Val
End Sub

Private Sub Text1_LostFocus()
    Text1Val = Val(Text1.Text)
    Text1.Text = Format(Text1Val, "$###,###,##0.00")
End Sub

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Start the App and type a number into text1. and see the effect of when it gets and looses focus..
As a 'Bonus' you could even add in this code to restrict the keys the textbox accepts..

Code:

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Private Sub Text1_KeyPress(KeyAscii As Integer)
If IsNumeric(Chr(KeyAscii)) Then
    Exit Sub
End If
If KeyAscii < 20 Then ' also allow control keys.
    Exit Sub
End If
KeyAscii = 0
End Sub

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If there is any chance that the value entered may not be numeric then then way to go is to first test it using IsNumeric() then use the CCur() or CLng() or whatever suits.