Question

i have the following methods:

    public  int CountProperty1
    {
        get
        {
            int count = 0;
            foreach (var row in Data)
            {
                count = count + row.Property1;
            }
            return count ;
        }
    }

    public  int CountProperty2
    {
        get
        {
            int count = 0;
            foreach (var row in Data)
            {
                count = count + row.Property2;
            }
            return count ;
        }
    }

what is the best way to avoid duplication here and share as much code as possible

Answer 1

How about using LINQ and the Sum extension method ?

public int CountProperty1 
{
    get { return Data.Sum(r => r.Property1); }
} 

In case that is not an option, you can refactor out the logic into your own sum method:

public  int CountProperty1
{
    get
    {
        return CountProperty(r => r.Property1);
    }
}

public  int CountProperty2
{
    get
    {
        return CountProperty(r => r.Property2);
    }
}

private int CountProperty(Func<Row,int> countSelector)
{
     int count = 0;
     foreach (var row in Data)
     {
         count = count + countSelector(row);
     }
     return count ;
}

Note about the last example: I made up the “Row” type, as it was not evident from your example. Substitute with the proper type.