Question

I have the following code –

    var db = new DBEntities();
    var entity = //get entity;

    lblName.Text = string.Empty;
    var names = entity.Names.OrderBy(x => x.Value).ToList();
    for (var i = 0; i < names .Count; i++)
    {
        if (i == names .Count - 1) lblName.Text += names [i].Value + ".";
        else lblName.Text += names [i].Value + ",&nbsp;";
    }

I’ll have several For loops like above which will format the value to be displayed in a label. I’m trying to make a method out of it which will do the formatting when I pass in the collection and the label, something like –

void FormatValue(List<??> items, Label label)
    {
        //For loop
        //Format value
    }

What do I pass in for the List. How do I make this generic enough so I’ll be able to use it for all entity.Names, entity.Xxx, entity.Yyy etc?

Answer 1

Make the method itself generic and allow the caller to specify a formatter:

void FormatValue<T>(List<T> items, Label label, Func<string, T> formatter)
{
    foreach(var item in items)
    {
        label.Text += formatter(item);
    }
}

You can then call the method like:

FormatValue<Name>(entity.Names.OrderBy(x => x.Value).ToList(),
                  lblName,
                  i => i.Value + ", &nbsp;");