Trappable Errors

[martim07]

Is there an error that can be raised to replace IsNumeric?

Thanks!

[Rick Rothstein]

> Is there an error that can be raised to replace IsNumeric?

I'm not sure what that question is supposed to mean. What is it you are
trying to do?

Rick - MVP

[martim07]

I want to validate textbox input. I need to make sure that there is
something entered and that the entered value is a number. I don't want
to use IsNumeric or Len(...). I want to get into trapping and handling
errors. Thanks.




"Rick Rothstein" <ri************@NOSPAMcomcast.net> wrote in message news:<d4********************@comcast.com>...

Is there an error that can be raised to replace IsNumeric?

I'm not sure what that question is supposed to mean. What is it you are
trying to do?

Rick - MVP

[Steve Gdula]

ma******@hotmail.com (martim07) wrote in message news:<85**************************@posting.google. com>...

I want to validate textbox input. I need to make sure that there is
something entered and that the entered value is a number. I don't want
to use IsNumeric or Len(...). I want to get into trapping and handling
errors. Thanks.

It sounds like you are making things harder on yourself than
necessary.

Use the 'VAL' function: dblValue=VAL(txtBox.text)
Right out of the MSDN Library---------------------------------------
The Val function stops reading the string at the first character it
can't 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. However, the function recognizes the radix
prefixes &O (for octal) and &H (for hexadecimal). Blanks, tabs, and
linefeed characters are stripped from the argument.

---------------------------------------------------------------------
You need decision logic to test for the returned value at some event:
if dblValue<1 then
err.raise (someErrorNum) 'Explicitly raise an error

or alternately you can:
dblResult=1/dblValue 'This will also raise an error if dblValue is
zero.

It it up to you to catch the errors.

--Steve.

[Rick Rothstein]

> I want to validate textbox input. I need to make sure that there is

something entered and that the entered value is a number. I don't want
to use IsNumeric or Len(...). I want to get into trapping and handling
errors. Thanks.

There is no (practical) way to get VB to recognize a non-numeric input to a
TextBox as being an error without checking to see that it is not a number
and using Err.Raise to force the error. Of course, that would be silly to do
since as soon as you know it is not what you want, you can react to it then
and there without wasting VB's time forcing it to generate an error.

Checking with Len to see if anything was typed is the standard way to check
if the TextBox is empty. You might want to use Trim$ inside of the Len
function to catch instances where the **only** thing the user typed was one
or more blank spaces. As for deciding if the user's entry is a number or
not, here are two functions that I have posted in the past for similar
questions..... one is for digits only and the other is for "regular"
numbers:

Function IsDigitsOnly(Value As String) As Boolean
IsDigitsOnly = Not Value Like "*[!0-9]*"
End Function

Function IsNumber(ByVal Value As String) As Boolean
' Leave the next statement out if you don't
' want to provide for plus/minus signs
If Value Like "[+-]*" Then Value = Mid$(Value, 2)
IsNumber = Not Value Like "*[!0-9.]*" And _
Not Value Like "*.*.*" And _
Len(Value) > 0 And Value <> "." And _
Value <> vbNullString
End Function
Rick - MVP

[Gary W.]

"Rick Rothstein" <ri************@NOSPAMcomcast.net> wrote in message
news:3E********************@comcast.com...

I want to validate textbox input. I need to make sure that there is
something entered and that the entered value is a number. I don't want
to use IsNumeric or Len(...). I want to get into trapping and handling
errors. Thanks.
There is no (practical) way to get VB to recognize a non-numeric input to

a TextBox as being an error without checking to see that it is not a number
and using Err.Raise to force the error. Of course, that would be silly to do since as soon as you know it is not what you want, you can react to it then and there without wasting VB's time forcing it to generate an error.

Checking with Len to see if anything was typed is the standard way to check if the TextBox is empty. You might want to use Trim$ inside of the Len
function to catch instances where the **only** thing the user typed was one or more blank spaces. As for deciding if the user's entry is a number or
not, here are two functions that I have posted in the past for similar
questions..... one is for digits only and the other is for "regular"
numbers:

Function IsDigitsOnly(Value As String) As Boolean
IsDigitsOnly = Not Value Like "*[!0-9]*"
End Function

Function IsNumber(ByVal Value As String) As Boolean
' Leave the next statement out if you don't
' want to provide for plus/minus signs
If Value Like "[+-]*" Then Value = Mid$(Value, 2)
IsNumber = Not Value Like "*[!0-9.]*" And _
Not Value Like "*.*.*" And _
Len(Value) > 0 And Value <> "." And _
Value <> vbNullString
End Function
Rick - MVP

These methods all work- however I use a much simpler method..

For the text box I use the KeyPress event:
Text1_KeyPress(KeyAscii as Integer)

Select Case KeyAscii
Case 48 to 57, 8
Case Else
KeyAscii = 0
End Select

Works in that NO non-numeric input *can* be entered. 48 to 57 are the ASCII
codes for 0 through 9 and 8 is ASCII for backspace (in case user makes a
mistake? Hey... it's been known to happen!)

For the textbox event (to see if anything was written) would it not be
easier just to write:

If text1.text = "" Then
MsgBox "Write your message here"
text1.SetFocus
End If
???

Would that help you more?

Gary - MCP

[Rick Rothstein]

See inline comments...

Function IsDigitsOnly(Value As String) As Boolean
IsDigitsOnly = Not Value Like "*[!0-9]*"
End Function

Function IsNumber(ByVal Value As String) As Boolean
' Leave the next statement out if you don't
' want to provide for plus/minus signs
If Value Like "[+-]*" Then Value = Mid$(Value, 2)
IsNumber = Not Value Like "*[!0-9.]*" And _
Not Value Like "*.*.*" And _
Len(Value) > 0 And Value <> "." And _
Value <> vbNullString
End Function
Rick - MVP

These methods all work- however I use a much simpler method..

For the text box I use the KeyPress event:
Text1_KeyPress(KeyAscii as Integer)

Select Case KeyAscii
Case 48 to 57, 8
Case Else
KeyAscii = 0
End Select

Works in that NO non-numeric input *can* be entered. 48 to 57 are the

ASCII codes for 0 through 9 and 8 is ASCII for backspace (in case user makes a
mistake? Hey... it's been known to happen!)
If you are trying to restrict entry to only numbers, the above will not
protect against the user Pasting in non-numeric characters. Two camps have
formed over data verification... the first is like your proposal, do it at
entry time; the other is let the user type what they want without bothering
them during the entry process and proof it later (which is what my functions
would be used for and, I believe, is what the OP asked for).

For the textbox event (to see if anything was written) would it not be
easier just to write:

If text1.text = "" Then
MsgBox "Write your message here"
text1.SetFocus
End If
???

While Text1.Text = "" works, believe it or not, Len(Text1.Text) = 0 executes
faster. However, I would do as I suggested in my first post and use
Trim$(Text1.Text) instead of Text1.Text directly... that way you protect
against the user accidentally entering a blank space into the TextBox.
Rick - MVP