Pass a generic list to a fuction and sort it (.Net Framework 4.8)-CodePudding

I have this function:

private void ReadFilesCommon<T>(string path, List<Class> Data, IParser Iparser, Func<KeyValuePair<string, object>, T> ClassCreator)
        {
            foreach (List<KeyValuePair<string, object>> entry in Iparser.ParseFiles(path)) // Files
            {
                foreach (KeyValuePair<string, object> entry2 in entry)
                {
                    Data.Add(ClassCreator(entry2));
                }
            }

            Data.Sort(delegate (Class t1, Class t2)
            {return (t1.name.CompareTo(t2.name));});

            
            return;
        }

Being Class the variable.

I want to make a function that can receive a list of some class (that has .name in it) and be able to sort it.

The problem is, if i make it generic, it loses the .name, so i can't sort it.

CodePudding user response：

You need either introduce an interface (or abstract class) which will expose the name property, implement it in the corresponding classes and restrict generic type to it via constraint:

public class IHaveName
{
   public string name {get; set;}
} 

private void ReadFilesCommon<T>(string path, 
    List<T> Data, 
    IParser Iparser, 
    Func<KeyValuePair<string, object>, T> ClassCreator) where T : IHaveName
{
    // ...
}

Or provide extra parameter which will represent function returning the sort field, depending on how generic you want it be it can be just string or another generic parameter:

private void ReadFilesCommon<T>(string path, 
    List<T> Data, 
    IParser Iparser, 
    Func<KeyValuePair<string, object>, T> ClassCreator, 
    Func<T, string> sortBy
)
{
    // ...
    Data.Sort(delegate (T t1, T t2)
            {return (sortBy(t1).CompareTo(sortBy(t2)));});
}

And usage looking something like ReadFilesCommon(..., t => t.name).

P.S. I recommend to follow standard naming conventions.

CodePudding user response：

I am not sure about your List<Class> type. I think you might be confused about generics, but that's just me. But I hope this helps:

I would classes implement IComparable:

void ReadFilesCommon<T>(...) where T : IComparable
{
    ...
    // you don't need delegate
    data.Sort();
}

..or pass in IComparer (or your delegate) as an additional argument:

void ReadFilesCommon<T>(... ICopmarer<T> comparer)
{
    ...
    data.Sort(comparer);
}

See List.Sort docs for more.