Validate data with Regular Expressions.
Regular expressions provide a flexible and efficient way to process text. Their extensive pattern-matching notation lets you to quickly parse large amounts of text to find specific character patterns and to extract, edit, replace, or delete text substrings.

Find unique words in documents using Regular Expressions.
Regular Expressions have extensive pattern-matching notation that can be used extract substrings matching certain patterns.

Use MeasureString to measure a string's height and width.
"Graphics.MeasureString", exposed by the "PaintEventArgs" parameter of the "Paint" event, measures a string when drawn with a specified font and returns a structure containing its height and width in pixels.

Convert Strings to Byte Arrays and Back.
Convert Strings to Byte Arrays and Back in .NET with the "System.Text.Encoder" namespace.

Determine if a string value is numeric in C#.
Check if a string value is numeric in C#, similar to VB's "IsNumeric" function.