Vb code for validating textbox

The Lost Focus() event occurs when the input focus leaves the control.

The Private void txt Cr_Lost Focus()event occurs when the input focus leaves the debit text box control.

In a perfect world, your code would run correctly every time.

You will first see the programming you can use to handle errors, and then you will see how to use validation techniques to prevent bad data from being entered into your application in the first place.

Set Focus End If first of all don't rely on implicit conversion, but use val() or cint() to convert the text to an integer ...

Caption = " Please enter you answer numericly " txt Amount. Set Focus 'HERE IS WHAT I WANT TO FIX End If If (txt Amount. Caption = " Please enter amount to convert" txt Amount.

But in the real world, you need to handle unexpected problems when your code is running.

A name doesn't generally contain weird symbols, and definitely not numbers. This can be from the mouse clicking inside another field, or a Tab key being pressed to navigate to the next input control. ") Else Email Valid = True 'Email is Perfect End If Else 'Not A Match To Pattern Email Valid = False 'Set Boolean Variable To False Message Box. I hope you have learned from this article and that you have enjoyed it as much as I did.

In this chapter, we'll look at two facets of dealing with problems in . First, we'll demonstrate the programming that you can do to handle errors, allowing the user to make corrections when something goes wrong.

Then, we'll demonstrate how you can use validation techniques to prevent bad data from being entered into your application in the first place.

That may seem like Captain Obvious speaking, but you'll be amazed at some of the data that gets entered into a name field. I then created an If statement to determine how the input data was formatted and whether or not the data is only alphabetic.

Sometimes people are just trying to be funny, or they are literally trying to break your program. If the data is indeed only alphabetic letters (no symbols, no numbers or any other punctuation characters) the test succeeds and stores True inside the Name Valid variable. This is because it becomes more legible than just a normal set of numbers.