Linq OrderBy breaks with navigation property being null

Question

Working with four tables.

Users -> has basic user info including a userid and a departmentid (int)
Groups -> basic group info including a groupid
GroupsMembers -

Answer 1

How about using the coalesce operator?

userQuery = userQuery.OrderBy(u => u.Department.Name ?? string.Empty);

Answer 2

You can use the conditional operator to check if the department is null :

userQuery = userQuery.OrderBy(u => (u.Department != null) ? u.Department.Name : String.Empty);

For improved clarity, I created the following extension method :

    public static TResult IfNotNull<TSource, TResult>(this TSource obj, Func<TSource, TResult> selector, TResult defaultValue)
    {
        if (obj != null)
            return selector(obj);
        return defaultValue;
    }

It can be used as follows :

userQuery = userQuery.OrderBy(u => u.Department.IfNotNull(d => d.Name, String.Empty));