For-Loop and LINQ's deferred execution don't play well together
- by Tim Schmelter
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<string[]> dynamically by each "column", beginning with the first and ending with the minimum Length of all arrays.
So in this sample it is 2, because the last string[] has only two elements:
List<string[]> someValues = new List<string[]>();
someValues.Add(new[] { "c", "3", "b" });
someValues.Add(new[] { "a", "1", "d" });
someValues.Add(new[] { "d", "4", "a" });
someValues.Add(new[] { "b", "2" });
Now i've tried to order all by the first and second column. I could do it statically in this way:
someValues = someValues
.OrderBy(t => t[0])
.ThenBy(t => t[1])
.ToList();
But if i don't know the number of "columns" i could use this loop(that's what I thought):
int minDim = someValues.Min(t => t.GetLength(0)); // 2
IOrderedEnumerable<string[]> orderedValues = someValues.OrderBy(t => t[0]);
for (int i = 1; i < minDim; i++)
{
orderedValues = orderedValues.ThenBy(t => t[i]);
}
someValues = orderedValues.ToList(); // IndexOutOfRangeException
But that doesn't work, it fails with an IndexOutOfRangeException at the last line. The debugger tells me that i is 2 at that time, so the for-loop condition seems to be ignored, i is already == minDim.
Why is that so?
