Textbox validating event
Unfortunately, development and validation of User Forms is rarely this simple. This is to check whether the Text Box is empty or not.
If this code was not in there, our error message would display twice, once if the user entered invalid data and again when we change the Text Box text to the VBNull String.
The focus can be set by the user or by the application.
In the last lesson we looked at validating a users input via the means of various Methods and Functions.
This type of validation can be of benefit to the user as well as ourselves.
For cases like these, the decision is relatively simple.
It would make no sense to allow the user to type in a string of text only then to inform him/her later on that the entry is not valid.