C# list count with data validation

Question

Thanks for your feedback. I'm still getting an out of range exception. I'm debugging but can't understand why I'm getting the exception. If an int is higher than a certain other int it should work. Does it have anything to do with the length.Count?

UPDATED Code

                    do
                {
                    Console.Write("Input the element that you want to exclude from the list: ");
                    result = int.TryParse(Console.ReadLine(), out delSelection);

                    tempInputDelInt = (int)(tempList[delSelection]);
                    tempInputDelStr = Convert.ToString(tempInputDelInt);

                    if (result == true && tempInputDelInt >= 0 && tempInputDelInt < tempList.Count)
                    {
                        tempList.RemoveAt(delSelection);
                        Console.WriteLine("\nYou've deleted the temperature " + tempInputDelStr + " from index " + delSelection);
                        success = false;
                        Console.ReadKey(true);
                        Console.Clear();
                    }

                    else if (result == true && tempInputDelInt >= tempList.Count || tempInputDelInt < 0)
                    {
                        Console.WriteLine("You've input a number that's outside the list. Input a digit between 0 and " + (tempList.Count - 1) + ".\n");
                        success = true;
                        Console.ReadKey(true);
                    }

                    else if (result == false)
                    {
                        Console.WriteLine("\nYou didn't input a digit, try again!\n");
                        success = true;
                        Console.ReadKey(true);
                    }
                } while (success);
                success = false;

I'm having some problems with the validation of the first else if statement. I want to catch the cases when a value outside of the array is input, but I don't manage to.

I've done a practically identical program with array.Length with success.

Is there any difference between array.List and list.Count? Is that's the problem?

Thanks in advance for your help!

                    do
                {
                    Console.Write("Input the element that you want to exclude from the list: ");
                    result = int.TryParse(Console.ReadLine(), out delSelection);


                    tempInputDel = Convert.ToString(tempList[delSelection]);

                    if (result == true && delSelection >= 0 && delSelection < tempList.Count)
                    {
                        tempList.RemoveAt(delSelection);
                        Console.WriteLine("\nYou've deleted the temperature " + tempInputDel + " from index " + delSelection);
                        Console.ReadKey(true);
                        Console.Clear();
                    }

                    else if (result == true && delSelection >= tempList.Count || delSelection < 0)
                    {
                        Console.WriteLine("You've input a number that's outside the list. Input a digit between 0 and " + (tempList.Count - 1) + ".\n");

                    }

                    else if (result == false)
                    {
                        Console.WriteLine("\nYou didn't input a digit, try again!");
                        Console.ReadKey(true);
                    }
                } while (result == false);

score 1 · Accepted Answer · answered Apr 02 '16 at 17:32

1

Change this

tempInputDelInt = (int)(tempList[delSelection]);

to this

tempInputDelInt = (int)delSelection;

Whatever number the user enters, you're using that as the index to determine which item to delete. So it's not a value you get from tempList.

answered Apr 02 '16 at 17:32

Scott Hannen

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@MaxModestoWallin You should thank him by accepting his answer. – RhinoDevel Apr 03 '16 at 18:47

score 0 · Answer 2 · answered Apr 02 '16 at 17:13

I am assuming that your out-of-range exception happens here:

tempInputDel = Convert.ToString(tempList[delSelection]);

You cannot do this before checking, if delSelection is inside range of tempList. Move it inside first if block.

General advice:

You can use a debugger to go from statement to statement step-by-step to find the exact source code position where (e.g.) an exception is thrown.

C# list count with data validation

2 Answers2