The name of a public or internal field in C# does not begin with an upper-case letter.
A violation of this rule occurs when the name of a public or internal field begins with a lower-case letter. Public or internal fields must being with an upper-case letter.
If the field or variable name is intended to match the name of an item associated with Win32 or COM, and thus needs to start with a lower-case letter, place the field or variable within a special NativeMethods class. A NativeMethods class is any class which contains a name ending in NativeMethods, and is intended as a placeholder for Win32 or COM wrappers. StyleCop will ignore this violation if the item is placed within a NativeMethods class.
How to Fix Violations
To fix a violation of this rule, change the name of the field so that it begins with an upper-case letter, or place the item within a NativeMethods class if appropriate.