PascalCase for WinForms Controls - Always

PascalCase is used for readability and consistency.  It aligns with how .NET controls are named, such as Button, Label and ComboBox.  

In fact, all public types and members are in PascalCase. Private fields are often in camelCase or _camelCase.

What is Snake Case in Computer Programming?

Snake case is a way of writing compound words, so that each word is separated by an underscore symbol. An example would be "cavendish_laboratory" or "sainsbury_laboratory". 

It is meant to be easier to read than camelCase, _camelCase or PascalCase.

A variant, Kebab Case, uses dashes and though commonly found in URLs, is also used in other contexts e.g. SPARQL-QUERY.