Entity Framework: Dealing with Nulls in Lambda Expressions

Been too long since I put a post up, this little gotcha seems a good time to add to this.

Writing a lambda expression for work I couldn’t understand why I was getting no result back when there was obviously a result in the database. The lambda expression was similar to below :

var record =  unitOfWork.Applications.Where(
                x =>
                x.Code == "U"
                && x.Decision != "R"
                && x.UserID == userId).FirstOrDefault();

Seems a pretty straight forward statement, but no value being returned, I realised in this instance the value for the Decision field in the database record was null and so this was not equating, NULL != “R” is returning false so the solution was to check for the null.  The change below fixed it using a ternary expression –> Expression : True : False

var record =  unitOfWork.Applications.Where(
                x =>
                x.Code == "U"
                && x.Decision == null ? true : x.Decision != "R"
                && x.UserID == userId).FirstOrDefault();

Simples

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