Exception in LinqExecutor OrderBy when a model and entity have different data types

[tspence]

Version 0.9.19 generates an exception when ordering by a DateTime value

[tspence]

Apparently this only fails on nullable datetime types, not regular datetime types.

[tspence]

Okay, this is odd. I haven't been able to repro it in my test suite. The error being thrown is System.InvalidOperationException: No generic method 'OrderBy' on type 'System.Linq.Queryable' is compatible with the supplied type arguments and arguments. No type arguments should be provided if the method is non-generic. - it seems there is some subtle difference between the test suite that is failing and the Searchlight test suite that is passing.

[tspence]

Found the root cause. Our unit test was sorting on a column, InvoiceDate, which is stored as a string in the API model but is stored as a DateTime? in the database. The root cause of this is the difference between the model data type and the database data type - it was failing to match the correct types.

[tspence]

Solution is to add this annotation to the model:

[SearchlightField(FieldType = typeof(DateTime?))]

This tells Searchlight to correctly query the field by its raw type.

[tspence]

Possible solutions:

• Scan for the exact entity type at runtime when the OrderBy field is calculated rather than using the compile-time type
• Scan for types when the SearchlightEngine is constructed using an "underlying data type"
• Catch this exception and handle it in some fashion at runtime, perhaps by converting it to a more clear exception message

[tspence]

Addressed by #106