How to create common connection in c# for Windows CE based .net application?
I have one barcode scanner, I want to use only one mysql connection at each form becaue opening connection on each form taking too much time. And my device connect server via wifi so.

Create a new public class and declare a static connection string public static string SqlConnection = Your .sdf connection string or just declare an actaul SqlCeConnection instead of a string. Just remember to add your using statements to the class. you can then call this anywhere in your application by typing the ClassName.SqlConnection.