Start Vb net textbox validating

Vb net textbox validating

Public Enum Check Type ct String = 0 ct Real = 1 ct Decimal = 2 ct Integer = 3 ct Byte = 4 End Enum Private m Allow Negative As Boolean = True Private m Allow Null As Boolean = True Private m Check Type As Check Type = Check String _ Private Sub Rule Check Me() '// Rule Checking If Me. Text Length = 0 Then If m Allow Null = False Then Main. Text Box1, "You are required to provide this value.") Me. Length 0 Then 'TODO: Figure out how to cope with input masks!

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.

You could say that a program's testers are supposed to do this; yes, they should - nobody else should. If not, if there is even just one unallowed character that is not supposed to be there, the Match method will return False. Instead of you having to loop through each character to determine what that character is, you simply need the correct Regular Expression pattern. Clear() Surname Valid = False Else Surname Valid = True End If End Sub It is basically the exact same code for the Name box, but I just included the capability to comprehend a space character as well. People expect to enter a phone number in a format similar to this: ###-###-####.

Let's say you have a form with textbox control, textbox1.

Place an errorprovider control on the form (it is not a visible control).

Well, sometimes a good structured and thought out If statement can suffice, but it can become quite long and cumbersome in the future. By using Regular Expressions this way, you can reduce the chances of getting errors at erratic times. This sub checks the email's format and if it thinks that it matches, it returns True and vice versa.

Also, the more tests you are performing, the slower your app might become. For more information regarding Regular Expressions, you are welcome to look at these two MSDN articles: Because it is always easy to learn by doing things practically, you will be creating an app that makes use of Regular Expressions to determine valid input. NET application and design the form to resemble Figure 1. Obviously this only works for the formatting of the email.

Valid = False Else If m Check Type = Check Byte And CType(Me. Text, Integer) Dim err Provider As New Error Provider ' Verify that this field is not blank.

Text Box1, "This field does not accept negative values.") Me.

Dim txt As Text Box = Direct Cast(sender, Text Box) ' See if it’s blank.

Private Sub Form1_Form Closing(sender As Object, e As Form Closing Event Args) Handles Me.

There are multiple values to handle this: annoy them when they try to paste text from somewhere else.