>This is a basic question to enhance my understanding.
>
>In a loop is the condition tokenized once and checked every time or is it calculated in every iteration?
>
>Take this example:
>

>for (int i = 0; i < this.TreeView1.Nodes.Count; i++)
>{
>}
>

>
>or is it more efficient (faster) to do:
>

>int nCount = this.TreeView1.Nodes.Count;
>for (int i = 0; i < nCount; i++)
>{
>}
>

>
>Granted, in a short loop it does not really matter as the time differences would be measured in microseconds but the principle of the thing is what I'm looking for.
>
>Every little bit of new knowledge on .NET helps :)

Hmm, good question. I'm not sure that fundamentally there is any difference in your two snippets. Since it's possible that the code in the loop could change either this.TreeView1.Nodes.Count or nCount, then the question really boils down to whether the value is re-evaluated for each loop, or if it's fixed at the start of the first loop. I don't know the answer to that off the top of my head.

It's probably infinitesimally quicker to use nCount instead of this.TreeView1.Nodes.Count, assuming there are enough loops to offset the overhead of declaring and initializing the extra variable. There could be a large speed gain if TreeView1 is an ActiveX; my understanding is that COM calls like that are expensive and that your second snippet is best practice in these cases.

UPDATE: Docs for the C# FOR command:

"The for loop executes a statement or a block of statements repeatedly until a specified expression evaluates to false."

Seems to me, this means the logical expression is evaluated before each loop, not just once.