问题
Using Database first design and having tinyint (or smallint) column:
[MyEnumColumn] [tinyint] NOT NULL
I mapped this column to Enum Type in EDM with
External Type: NSpace.MyEnumType
Name:MyEnumType
UnderlyingType:Byte
Where NSpace.MyEnumType is defined like this:
public enum MyEnumType
{ One, Two, Three, All }
Only to get this error when trying to load entity from context:
Schema specified is not valid. Errors:
No corresponding object layer type could be found for the conceptual type 'EntityDataModel.MyEnumType'.
The following information may be useful in resolving the previous error:
The underlying type of CLR enumeration type does not match the underlying type of EDM enumeration type.
Same applies if I use [Smallint] and [Int16] but once I change database to [Int] and enum type to [Int32] the error is gone.
Why do I need to store enum value in 4Byte (Int) data field instead of 1Byte (Tinyint) when enums in 99.9% time don't have more than 256 items or am I missing something else?
回答1:
Well if anyone is interested the problem is in enum's default type:
public enum MyEnumType
{ One, Two, Three, All }
Since enum defaults to type int, [Underlying Type:{Byte}] doesn't match type of [External Type] {MyEnumType:Int} so to fix it for my original tinyint field you need to define your enum like this:
public enum MyEnumType : byte
{ One, Two, Three, All }
回答2:
You need to specify both in the Model and in the Enumerator that you are using tinyInt and Byte .
in Enumerator definition
public enum MyEnumType : byte
{ One, Two, Three, All }
then in the Model class file
[Column(TypeName = "tinyint")]
public MyEnumType? MyEnum { get; set; }
来源：https://stackoverflow.com/questions/13318782/tinyintbyte-smallintint16-not-compatible-with-enum-in-ef5