Answer by Rm558 for LINQ equivalent of foreach for IEnumerable

ForEach can also be Chained, just put back to the pileline after the action. remain fluent

Employees.ForEach(e=>e.Act_A)
         .ForEach(e=>e.Act_B)
         .ForEach(e=>e.Act_C);

Orders  //just for demo
    .ForEach(o=> o.EmailBuyer() )
    .ForEach(o=> o.ProcessBilling() )
    .ForEach(o=> o.ProcessShipping());


//conditional
Employees
    .ForEach(e=> {  if(e.Salary<1000) e.Raise(0.10);})
    .ForEach(e=> {  if(e.Age   >70  ) e.Retire();});

An Eager version of implementation.

public static IEnumerable<T> ForEach<T>(this IEnumerable<T> enu, Action<T> action)
{
    foreach (T item in enu) action(item);
    return enu; // make action Chainable/Fluent
}

Edit: a Lazy version is using yield return, like this.

public static IEnumerable<T> ForEachLazy<T>(this IEnumerable<T> enu, Action<T> action)
{
    foreach (var item in enu)
    {
        action(item);
        yield return item;
    }
}

The Lazy version NEEDs to be materialized, ToList() for example, otherwise, nothing happens. see below great comments from ToolmakerSteve.

IQueryable<Product> query = Products.Where(...);
query.ForEachLazy(t => t.Price = t.Price + 1.00)
    .ToList(); //without this line, below SubmitChanges() does nothing.
SubmitChanges();

I keep both ForEach() and ForEachLazy() in my library.