I have class grades that I need to check if a specific grade is pass or fail. This is the list of grades in order:
If B is the pass mark, and The student has B+, using the normal ordering, if I check if the studentGrade > passMark, then its going to say it is failed because the system orders the strings as follows:
How do I setup a custom comparer for ordering a list as the first list in c#?
You can create a custom class that implements IComparer<string>, and use it to do the ordering as needed.
That being said, grades are often handled numerically instead of via string comparisons. Using a numeric value would make this far simpler.
Using the sort method of the List<> class and providing a custom Comparison is the way to go (at least one way).
How about an Enum to give them a weight?
public enum ComparisonType
{
A = 1,
AM = 2,
BP = 3,
B = 4,
BM = 5
}
It makes it easier when creating a custom comparer.
public class GradeComparer : IComparer {}
After that its a breeze by calling the .Sort() method on your list and voila.
try this :
public class MyComparer : IComparer<MyObject>
{
public int Compare(string s1, string s2)
{
var grad1 = s1.Replace('+','1').Replace('-','2');
var grad2 = s2.Replace('+','1').Replace('-','2');
if (grad1 > grad2)
retun 1;
else if (grad1 < grad2)
return -1;
else
return 0;
}
}
List<string> list = new List<string>{"A","A+","A-"};
var sortedList = list.OrederBy(o=>o,new MyComparer()).OrderBy(o=>o.Length);
