For-Loop and LINQ's deferred execution don't play well together

Question

The title suggests that i\'ve already an idea what\'s going on, but i cannot explain it. I\'ve tried to order a List dynamically by each \"colum

Answer 1

This is probably happening because the value of i is not closed within the loop - when the loop exits, i will have a value of 2 and then t[i] will be evaluated because of deferred execution.

One solution is to create a closing variable within the loop:

int minDim = someValues.Min(t => t.GetLength(0));  // 2
IOrderedEnumerable orderedValues = someValues.OrderBy(t => t[0]);
for (int i = 1; i < minDim; i++)
{
    var x = i;
    orderedValues = orderedValues.ThenBy(t => t[x]);
}
someValues = orderedValues.ToList();