使用 IEnumerable<T> 使用模板制作通用方法

Question

我希望将两个具有相似代码但变量类型不同的函数结合起来。我想在IEnumerable 中使用 T 类型，但它似乎不起作用。

方法一：

public static IList<ListItem> AppendTopMakesToList(this IEnumerable<ListItem> options, bool appendSeparatorRow = true)
{
    if (options == null || string.IsNullOrEmpty(Sitecore.Configuration.Settings.GetSetting("RACQ.JoinMembership.Top10CarMakes"))) 
        return options.ToList();

    var topmakes = Sitecore.Configuration.Settings.GetSetting("RACQ.JoinMembership.Top10CarMakes").Split('|').ToList().ConvertAll(d => d.ToLower());
    var filteredMakes = options.Where(x => topmakes.Any(y => y.Contains(x.Text.ToLower()))).ToList();//getting all the makes from the listItems

    if (appendSeparatorRow)
    {
        var separatorListItem = new ListItem("------------------", "------------------", false);
        separatorListItem.Attributes.Add("disabled", "true"); //disabling the separator item so that it can't be selected
        filteredMakes.Add(separatorListItem);
    }

    var items = options.ToList();
    items.InsertRange(0, filteredMakes);

    return items;
}

方法二：

public static IList<Make> AppendTopMakesToList(this IEnumerable<Make> options, bool appendSeparatorRow = true)
{
    if (options == null || string.IsNullOrEmpty(Sitecore.Configuration.Settings.GetSetting("RACQ.JoinMembership.Top10CarMakes"))) 
       return options.ToList();

    var topmakes = Sitecore.Configuration.Settings.GetSetting("RACQ.JoinMembership.Top10CarMakes").Split('|').ToList().ConvertAll(d => d.ToLower());
    var filteredMakes = options.Where(x => topmakes.Any(y => y.Contains(x.Code.ToLower()))).ToList();//getting all the makes from the listItems

    if (appendSeparatorRow)
    {
        var separatorListItem = new Make()
                {
                    Code = "------------------",
                    Description = "------------------"
                };

                filteredMakes.Add(separatorListItem);
            }

            var items = options.ToList();
            items.InsertRange(0, filteredMakes);

            return items;
        }
    }
}

这些函数与IList<Make> 和IList<ListItem> 的返回类型完全相同，后者是在IEnumerable<Make> 和IEnumerable<ListItem> 的参数类型上传递的。

Answer 1

我会这样做：

public static IList<T> AppendItems<T>(this IEnumerable<T> options, Action<T> blankFactory, bool appendSeparatorRow = true)
        {
            if (options == null || string.IsNullOrEmpty(Sitecore.Configuration.Settings.GetSetting("RACQ.JoinMembership.Top10CarMakes"))) return options.ToList();
            var topmakes = Sitecore.Configuration.Settings.GetSetting("RACQ.JoinMembership.Top10CarMakes").Split('|').ToList().ConvertAll(d => d.ToLower());
            var filteredMakes = options.Where(x => topmakes.Any(y => y.Contains(x.Code.ToLower()))).ToList();//getting all the makes from the listItems
            if (appendSeparatorRow)
            {
                var separatorListItem = blankFactory();
                filteredMakes.Add(separatorListItem);
            }
            var items = options.ToList();
            items.InsertRange(0, filteredMakes);
            return items;
        }

然后你可以像这样使用它：

var whatever = new List<ListItem>():


AppendItems(whatever, () => {
                var separatorListItem = new ListItem("------------------", "------------------", false);
                separatorListItem.Attributes.Add("disabled", "true");
    return separatorListItem;

}, true);