Input Validation in ASP.NET

Input validation is very important for web application because an open input field can lead to successful hack attempts, system crashes, malicious data manipulation, data corruption, and notorious Denial of Service (DoS) situation. ASP.NET has five built-in validator controls to make life easier. A validator is a control that checks one input control for a specific type of error condition and displays a description of that problem. These controls improve performance besides simplifying validations.

• RequiredFieldValidation
• CompareValidator
• RangeValidator
• RegularExpressionValidator
• CustomValidator

What is HL7?

• Full form of HL7: Health Level Seven
• Accredited standards to share clinical and administrative data
• Promoted by Health Level Seven Inc. (USA) Ann Arbor, MI (USA)
• Freely available without licenses or license fees 
• Copyrighted for accuracy and integrity
• HL7 message format: human readable ASCII
• HL7 message  -> consists of segments
• Over 120 different segment types are available
• Segments are separated by line feeds (\r or 0x0D)
• A segment begins with a three letter name such as MSH
• Segment examples: MSH (Message Header), PID (Patient Info)
• Segment -> consists composites (or fields)
• Composites are separated by | characters (or \F\)
• Composites may contain other composites (sub-composites or sub-fields)
• Sub-fields are separated by ^ characters (or \S\)
• Sub-composites may contain other composites (sub-sub-composites or sub-sub-fields)
• Sub-sub-fields are separated by & characters (or \T\)
• HL7 website: http://www.hl7.org/
• HL7 on Wikipedia: http://en.wikipedia.org/wiki/HL7
• HL7 glossary of terms: http://www.hl7.org/ehr/documents/public/documents/Glossary%20of%20terms.pdf