问题
Using Entity Framework Code First, the web application crashes on a call to DbContext with the following error:
Assertion failed
Expression: primitiveType != null
Description: Assertion failed: primitiveType != null
It crashes on the following line of code:
public class MyDb : DbContext {
which is called by:
MyDb _db = new MyDb();
So it seams like calling DbContext generates a fatal error. DbContext is an EF function and I cannot debug inside EntityFramework.dll
回答1:
It's a problem related to older versions of EntityFramework. It happens sometimes when copying a Visual Studio Project to a different machine. This can cause the application to calculate a different ModelHash than the one that is in the database (inside the EdmMetaData table). Solution is to delete the EdmMetaData table and use DbDatabase.SetInitializer<MyContext>( new DropCreateDatabaseIfModelChanges<MyContext>()); to put it back in place, or even better: Upgrade to a newer version of EntityFramework that is not utilizing the EdmMetaData table and ModelHashes.
回答2:
After installing asp.net4.5 I have same error. The Answer for me is to update Entity Framework to new version.
Deleting "EdmMetaData" table didn't resolve the error.
回答3:
I swicth to linq to sql and dint get this error. Dont know what entities is doing to cause this.
回答4:
You need to update your EntityFramework version
来源：https://stackoverflow.com/questions/10430223/dbcontext-crashes-with-primitivetype-null-error