Index in my list that's looped through by a for-loop is out of bounds. It must be non-negative and less than the size of the collection

Below is a code snippet of my ShowForm() method, which is used with my winforms.

The error I am receiving is:

Some diagnostic information:

1. I know that the if-statement is hit, because of a MessageBox.Show() method I put there. I am thinking the for-loop is somehow indexing out, but I'm not quite sure why it is doing so.

2. The x.Count: is 7

3. Doing MessageBox.Show(Params.Index[0].ToString()); to check if Params.Index[0] is empty crashes my program every time without fail. What could that mean?

Replies to This Discussion

Permalink Reply by Hen B3D on January 22, 2014 at 4:10pm

Hi,

Well the reason it's crashing is because you're trying to access an array in an invalid index.

You're accessing only two arrays Params.Input & x.

The access to x seems alright, tho you need to notice that you're accessing from index 0 to count - 1. which means if you have only 1 element in the array you're not accessing anything. you should lose the '-1' because you're already limiting the loop to a number that is < than count. (using -1 would be logical if you're limiting it by <=)

You need to check for Params.Input length before accessing it, my guess is that it's empty and therefor accessing it in the 0 index raises an exception. and that is your bug

for your 3rd question -if you have an exception that is not handled Rhino will exit at once. Accessing Param.Input[0] WILL raise an exception if Param.Input is empty or null.

I suggest that next time before accessing any arrays make sure they're not null/empty and that your index is valid for that array.

Permalink Reply by Hen B3D on January 23, 2014 at 8:01am

You've also noticed that in the for loop that you're accessing 'x' you're not going through all the elements and quitting the loop before the last element?

If not, re-read what i wrote regarding that loop in my first reply.

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