I have a WPF Application using Fluent NHibernate 1.0 RTM and System.Data.SQLite 1.0.65 that works fine in .Net 3.5. When I try to upgrade it to .Net 4.0 everything compiles but I get a runtime error where the innermost exception is this:
`The IDbCommand and IDbConnection implementation in the assembly System.Data.SQLite could not be found.`
The only change made to the project was switching the Target Framework to 4.0.
If the acepted answer doesnt work for you, check if you have 64bit system, and if you do, right click on your project -> properties -> build -> set platform target to x86 and rebuild.
You need to use a version of SQLite that is compatible with .NET 4.0. You might also try putting this in your app.config: