ASP.Net Core Razor Pages: Server Side AlphaNumeric TextBox Validation (Alphabets and Numbers) characters

Here Mudassar Khan has explained an example, how to perform AlphaNumeric TextBox validation i.e. allow only Alphabet and Number characters on Server Side using Data Annotation in ASP.Net Core Razor Pages. The AlphaNumeric TextBox validation i.e. allow only Upper Case and Lower Case Alphabet and Number (Digits) characters validation will be performed using Regular Expression (Regex).