An unhandled exception of type 'System.ArgumentOutOfRangeException' occurred in mscorlib.dll

Question

In the following code, I got following error.

An unhandled exception of type 'System.ArgumentOutOfRangeException' occurred in mscorlib.dll

Additional information: Index was out of range. Must be non-negative and less than the size of the collection.

Here is code:

public ProcessInformation GetMaxRunTimeForApplicationsBetween(DateTime StartingTime, DateTime EndingTime)
    {

        //Filter Based on Timer
        List<ProcessInformation> filterList = new List<ProcessInformation>();

        foreach (HarvestApp.ProcessInformation item in this.ProcessList)
        {
            if (item.started_at.CompareTo(StartingTime) >= 0 && item.ended_at.CompareTo(EndingTime) <= 0)
            {
                filterList.Add(item);
            }
        }

        //Count Max Occurrence of Application
        List<int> countApplicationList = new List<int>();
        List<string> applicationNameList = new List<string>();
        

        foreach (HarvestApp.ProcessInformation item in filterList)
        {
            if (applicationNameList.Contains(item.name))
            {
                countApplicationList[applicationNameList.IndexOf(item.name)]++;
            }
            else
            {
                applicationNameList.Add(item.name);
                countApplicationList.Add(1);
                
            }
        }


        //if (countApplicationList.Count == 0)
        //{
        //    throw new InvalidOperationException("Empty list");
        //}


        int max = int.MinValue;
        foreach (int item in countApplicationList)
        {
            if (item > max)
            {
                max = item;
            }
         
        }
        
            //Return corresponding ProcessInformation Class of applicationNameList
            return filterList[filterList.FindIndex(delegate
                (ProcessInformation proc)
                {
                    return proc.name.Equals(applicationNameList[countApplicationList.IndexOf(max)], StringComparison.Ordinal);
                })];

       


    }

Solution

I think error line is here:

return filterList[filterList.FindIndex(delegate(ProcessInformation proc)
    {
        return proc.name.Equals(applicationNameList[countApplicationList.IndexOf(max)], StringComparison.Ordinal);
    })];

Because List<T>.FindIndex can return -1 when you can't find index.

Instead you should test if the index is less than 0, which indicates there is an error, before you use it:

int result = filterList.FindIndex(delegate(ProcessInformation proc)
        {
            return proc.name.Equals(applicationNameList[countApplicationList.IndexOf(max)], StringComparison.Ordinal);
        });

if(result < 0) throw new Exception("Cant't Find ProcessInformation"); 
return  filterList[result];

Comments

[Damien_The_Unbeliever]

Guessing C# from the exception name and the code style, but if not, please re-tag with an appropriate language tag.

[Mike Perrenoud]

This exception could occur in a number of places in this code. What line is it failing on? You know that much.

[Admin]

exception occurrs at return statement.

[Andre]

What about the stacktrace?

[Admin]

I tried this. But still gives me same exception. It shows problem at Return statement.

[Admin]

Yes. Error in return statement.