Regular Expression in Business Central - Validate fields using business central

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Introduction to Regular Expression

Information can be easily extracted from any text using regular expressions (regex or regexp) by searching for one or more matches of a given search pattern (that is, a particular set of ASCII or Unicode letters).

Validation, parsing/replacing text, translating data to different formats, and web scraping are just a few of the many possible applications.

Once you're familiar with the syntax, this tool may be used in virtually any programming language (JavaScript, Java, Visual Basic, C#, C/C++, Python, Perl, Ruby, Delphi, R, Tcl, and many more), with only minor differences across languages and engine versions for the most sophisticated functionality.

Let's get started with some illustrations and clarifications.

Basic Characters

Anchors - ^ and $

^The        matches any string that starts with The -> Try it!

end$ finds strings that end with that character.

Exact string matching (begins and ends with The end) with the value "^The end$"

roar finds any string that contains the word "roar"

Using Business Central's Regular Expression to verify the field

Before accepting a value supplied by a user, it can be necessary to verify that it follows a specific pattern. The RegEx dotNet libraries were used in earlier versions of Microsoft Dynamics NAV to facilitate regular expression validation.

In Business Central we have RegEx codeunits as a base application.

While Dynamics 365 Business Central does not include the RegEx dotNet libraries out of the box, a RegEx Codeunit is available for developers that need to use regular expressions to match text patterns. You can use the IsMatch technique built into the RegEx Codeunit to check if a given value satisfies a given Regular Expression.

Pattern := '[A-Z]{3}\-[0-9,A-Z]{3}

The above RegEx implementation example demonstrates the use of the IsMatch function to match a pattern consisting of three alphabetic characters followed by a hyphen and then any three alphanumeric characters (Good: GOM-123, Bad: 123-GOM):

We have to initialize the RegEx code unit in a variable as below

regex: Codeunit Regex;

The following code is used to validate the employee ID

Code snippet

field(EmpID; EmpID)

                {

                    ApplicationArea = All;

                     trigger OnValidate()

                    begin

                        Pattern := '[A-Z]{3}\-[0-9,A-Z]{3}';

                        if regex.IsMatch(EmpID, Pattern, 0) then

                            Message('Match')

                        else

                            Error('Please enter the valid input');

                    end;

                 }

The following code is used to validate the email id

field(email; email)

 {

                    ApplicationArea = All;

                    trigger OnValidate()

                    begin

                        Pattern := '^[a-zA-Z0-9+_.-]+@[a-zA-Z0-9.-]+$';

                        if regex.IsMatch(email, Pattern, 0)

                        then

                            Message('Matched')

                        else

                            Error('INvalid input');

                    end;

}

Please check the complete code here 

Check the complete video here to know how to validate the field and implement the above code.

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