Regular expression for validating a number
I’ll provide a few different methods to handle the actual validation through Regular Expressions and let you determine which one might best suit your needs.A Social Security number (SSN) is a nine-digit number issued to U. citizens, permanent residents and temporary residents under section 205(c)(2) of the Social Security Act.If there are no empty fields, then the following code validates the first name by calling the static method Match of the Regex class, passing both the string to validate and the Regular Expression as arguments. This object contains a Success property that indicates whether a method Match's first argument matches the pattern specified by the Regular Expression in the second argument.If the value of Success is false (i.e., there was no match), then it displays an error message and sets the focus back to the first Name Text Box so that the user can retype the input and terminate the event handler.They can be useful during information validation, to ensure that data is in a specified format.For example, a ZIP code must consist of five digits, and the last name must start with a capital letter.
(With thanks to Plasma Power and Casimir et Hippolyte for the debugging assistance.) Depending on what you are capturing, it is likely that all sub-groups should be made into non-capture groups. It turns out that the first approach (aliteralmind's answer) is far more economical. Speed Tests Here is the output of my simple speed test, matching from -1M to 1M. If all of the fields contain valid information, the program displays a message dialog stating this and the program exits when the user dismisses the dialog. But the input number must be in a range from -2055 to 2055 and I want to check this by using regular expression. If one or more fields are empty then the program displays a message to the user that all fields must be filled in before the program can validate the input information.The code above calls the first Name Text Box's Focus method to place the cursor in the first Name Text Box.
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If you would like leading zeroes, let me know, that is a very easy tweak. x) # free-spacing mode ^ # anchor at beginning of string.