ridernullchecks.cs

var keys = new[] {1, 2, 3};
var map1 = new Dictionary<int, string>();
var map2 = new Dictionary<int, string>();
var items =
    from key in keys
    let value1 = map1.GetValueOrDefault(key)
    where value1 != null
    let value2 = map2.GetValueOrDefault(key)
    let whatever = 123
    select new
    {
        Value1 = value1.ToUpper(),
        Value2 = value2 != null ? value2.ToUpper() : string.Empty
    };