Question

I have a list of fields which a user can sort using jquery. I save these updated fields in the database. The same fields can be added and removed from the report, so in some cases I will have field1, field55, field 3. The fields can appear in a random order (based on where it appears in the report).

I am trying to sort a list where in most cases the field will have a value but it can also be 0.

var list = Dictionary<string,int>(); //loaded from the client side, in-memory

I have a list where I use the method list.orderby(x=> x.Value); This will sort fields in the correct order, however I want to get the remaining fields whos order = 0, and append to the end of the list with the greatest number in the list.

e.g. the highest number in the list is 78, I have 4 fields that have the prop Order = 0, these fields should be 79,80,81,82 respectively.

Something like this may work, but I am getting a collection modified error:

        var max = list.Max(x => x.Value);

        foreach (var item in list.Where(x => x.Value == 0))
        {
            list[item.Key] = ++max;
        }

Answer 1

var list = new Dictionary<string, int>
    {
        {"Banana", 123},
        {"Apple", 234},
        {"Orange", 34},
        {"Pear", 4},
        {"Elephant", 99},
        {"UnOrderedItem1", 0},
        {"UnOrderedItem2", 0},
        {"UnOrderedItem3", 0},
        {"UnOrderedItem4", 0},
    };

int nextValue = list.Max(x => x.Value) + 1;
var elementsWithZero = (from l in list where l.Value == 0 select l)
    .ToList();

foreach (var item in elementsWithZero)
{
    list[item.Key] = nextValue++;
}

var sortedList = (from l in list select l)
    .OrderBy(x => x.Value);

foreach (var item in sortedList)
{
    Console.WriteLine("{0}: {1}", item.Value, item.Key);
}

Output:

4: Pear
34: Orange
99: Elephant
123: Banana
234: Apple
235: UnOrderedItem1
236: UnOrderedItem2
237: UnOrderedItem3
238: UnOrderedItem4