Build an OR query expression progressively [duplicate]

Answer 1

To accomplish what you ask without using the dynamic linq lib, you can define expressions for each test in the where clause, then use them to build a lambda expression:

Expression> isIndividualCustomer = c => c.CustomerType == "Individual";

Expression> territoryIdIs3 = c => c.TerritoryID == 3;

Expression> customerIsIndividualOrOfTerritoryId3 = Expression.Lambda>(
    Expression.Or(isIndividualCustomer.Body, territoryIdIs3.Body), isIndividualCustomer.Parameters.Single());

Usage:

var query = context.Customers.Where(customerIsIndividualOrOfTerritoryId3);