Error when deleting an item from collection

Question

I am trying to remove an element from Collection but ended up with error

Collection was modified; enumeration operation may not execute.

What i am trying to achieve?

Check Student list count in Report collection.

If count is == 1 Than check null or empty for Student properties

If all true than delete Student from Report collection..

Here is my code

public void Create(StudentReport report)
{

    ICollection<StudentReportDetails> student= report.Students;
    if (student.Count == 1) 

    {
        foreach (StudentReportDetails Studetails in student)
        {

            if (String.IsNullOrEmpty(Studetails.StudentNumber)&& String.IsNullOrEmpty(Studetails.Description) && String.IsNullOrEmpty(Studetails.Summary))
            {
                report.Students.Remove(Studetails);
            }

        }
    }
}

http://stackoverflow.com/questions/604831/collection-was-modified-enumeration-operation-may-not-execute — Soner Gönül, Aug 10 '15 at 08:10
As it says, you can't delete a collection item in an enumerator based loop. And we can understand why, in the current item is the way to the following. But you delete the current item, so, no following. — Guillaume Beauvois, Aug 10 '15 at 08:12
@ Garg Ankit why so harsh.. error is human nature. thanks for the edit. — TheKingPinMirza, Aug 10 '15 at 08:12

score 2 · Answer 1 · answered Aug 10 '15 at 08:09

2

Yes. You can't modify a collection. Foreach loop makes the collection as readonly.

answered Aug 10 '15 at 08:09

Karthik

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thanks for the info. i wasnt aware about it. – TheKingPinMirza Aug 10 '15 at 08:19

score 1 · Answer 2 · answered Aug 10 '15 at 08:14

If you want to modify it change foreach to for loop:

for (int i = 0; i < student.Count; i++)
{ 

        if (String.IsNullOrEmpty(Studetails.StudentNumber)&& String.IsNullOrEmpty(Studetails.Description) && String.IsNullOrEmpty(Studetails.Summary))
        {
            report.Students.Remove(Studetails);
        }

    }

Error when deleting an item from collection

2 Answers2