I am trying to filter the input to a textbox such that:

1. Only numerical values will be accepted.
2. A decimal point will only be allowed once.
3. Negative values will be allowed but only with
the -ve sign at the beginning of the input and
only being accepted once.

I have tried the DataFormat property and this does not seem to work. I seem to be able to trap the text values and decimal point constraints but the -ve has escaped me so far...

Any suggestions???

I am quite new to VB and may have missed something fundamental. Perhaps there is an API Function angle to this one with which I am not familiar...

Thanks