How used property linked list in c#?

I hope you saw the MSDN help page and code sample: http://msdn.microsoft.com/en-us/library/bb534966.aspx[^].

I suspect you don't understand (generics) delegates, lambda syntax (yes, for this simple application understanding syntax is quite enough) or maybe IEnumerable.
Lets see. You are required to supply a parameter, which is the method with the signature defined by the delegate type Func<TSource, TKey>. In your case, this is a function which accept one parameter which is of the type of your list element (double) and returns some key of the type for which the ordering operation is defined. So, your code sample is correct, if you need to return a collection in natural order.

Without the lambda, you could write equivalent code:

static double GetOrderingCriterionKey(double value) { return value; }

//...
IOrderedEnumerable<double> =
   arrayresultMembership.OrderBy(new Func<double,>(GetOrderingCriterionKey));

If you need to change the order, use other OrderBy methods, those using IComparer, see http://msdn.microsoft.com/en-us/library/he2s3bh7%28v=VS.100%29.aspx[^].

See also the definition of the generic delegate type Func. In your case, it is instantiated as

delegate double DoubleFunction(double element);

About IEnumerable and IOrderedEnumerable, just read and understand this: http://msdn.microsoft.com/en-us/library/system.collections.ienumerable.aspx[^],
http://msdn.microsoft.com/en-us/library/bb534852.aspx[^].

—SA