Question

I have a little problem with sorting out a list using an implementation of IComparer.

public struct VAL
{
    public int i;
    public string s;
}

public struct INFO
{
    public string name;
    public VAL val;
    public string address;
}

public class ListSorter:IComparer<INFO>
{
    public enum SORT_TYPE{BYNAME, BYVAL,BYADDRESS};
    public int Compare(INFO i1, INFO i2)
        {
        switch(sortType)
        {
            case SORT_TYPE.BYNAME;
                return string.Compare(i1.name, i2.name);
            case SORT_TYPE.BYADDRESS:
                return string.Compare(i1.address, i2.address); 
            case SORT_TYPE.BYVAL:
            {
                ??????
            }
        }
    }   
}

The comparison function in the class ListSorter is an example of how I am comparing strings in the given INFO struct. But I don’t know how to sort the list based on the VAL struct information members

Answer 1

Normally you would do something like:

case SORT_TYPE.BYVAL:
{
    int ret = i1.VAL.i.CompareTo(i2.VAL.i);
    if (ret != 0)
    {
        return ret;
    }
    return i1.VAL.s.CompareTo(i2.VAL.s);
}

You first compare the i and if they are equal you compare the s (or the opposite, the order must be selected by you).