为什么我不能用C＃将数据插入本地数据库（SQL Compact Edition）？

I am doing a project on Visual Studio. I am using a local database (empty sql server compact edition). I chose Dataset and created my table (Images). It has a primary autoincrement id column, and an nvarchar ImagePath column. I want to insert data in it and here is my code.I am doing a project on Visual Studio. I am usi