Foreach loop causes NullReferenceException

Question

At the top of my code (before constructor) I write: String[] CAN = null;

This string array is updated in another function.

Later in my code I have this foreach loop:

foreach (String str in CAN)
{
    if(str.Contains("18FA07FE"))
        cmdResult = true;
    else
        cmdResult = false;
}

I have tried to debug, and at the line of the foreach statement I can see that the CAN string array has successfully been updated, and now contains 1211 elements.

So I don't really know why it's giving me this exception.

Did you check the contents of your string array?..maybe one of the elements of the array is null. :) — sailhenz
– sailhenz, Commented Oct 6, 2011 at 7:32

Lasse V. Karlsen · Accepted Answer · 2011-10-06 07:31:48Z

4

If the problem is only related to the code you've shown, and the code you've described, and it's true that the array has elements, then the only possible explanation is that one of the elements in CAN is a null element, and thus it isn't the foreach itself that throws the exception, but this line:

if (str.Contains(...))
    ^^^
     |
     +-- null

answered Oct 6, 2011 at 7:31

Lasse V. Karlsen

394k107 gold badges651 silver badges845 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

sailhenz Over a year ago

I agree on that.. .just like i said in my first comment, check the string array. :)

gosr Over a year ago

Yeah thanks, it turned out that the very last element of the string array was null. Fixed now, cheers!

user474407 · Accepted Answer · 2011-10-06 07:36:08Z

2

Maybe one of the string value is a null

string [] CAN =  { "first", "second", null, "fourth" };

            foreach ( string str in CAN ) {
                if ( str.Contains( "fourth" ) ) {
                    Console.WriteLine( "Success" );
                }
            }

answered Oct 6, 2011 at 7:36

user474407

Comments

Hiery Nomus · Accepted Answer · 2011-10-06 07:32:50Z

0

Where do you get the NullPointer? Is it the loop or the if? I guess your array contains a 'null' element which throws this NPE.

answered Oct 6, 2011 at 7:32

Hiery Nomus

17.8k2 gold badges43 silver badges37 bronze badges

Collectives™ on Stack Overflow

Foreach loop causes NullReferenceException

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related