When using the SQLite database, "system. Data. Common. dbconnection" defines the cause of the error in the unreferenced assembly.

This is because "system. Data. Common. dbconnection" is not referenced when you use the SQLite database.ProgramCentralized definition error!

But soon I found the cause. I saw a lot of problems on the Internet, so I decided to write it out.

Two system. Data. SQLite. dll

First: C: \ Program Files \ SQLite. Net \ bin \ system. Data. SQLite. dll -------- (size: 883kb) for Windows Applications

Second: C: \ Program Files \ SQLite. Net \ bin \ compactframework \ system. Data. SQLite. dll ---------- (size: 478kb) handheld device (PDA)

Because the DLL files used for PDAs are smaller than those used for Windows applications, there is nothing available.

If you reference the first one in a Windows application, if you reference the second one in a mobile application

However, if you are running c: \ Program Files \ SQLite. net \ bin or in c: \ Program Files \ SQLite. net \ bin \ compactframework. data. SQLite. if you copy the DLL and reference it, it's easy to get the wrong object!

The reason for the above problem is that you applied system. Data. SQLite. DLL for the Windows application to the mobile program.