如何使用 LINQ 从另一个列表填充对象的属性

Question

我有 2 个对象列表。一个有值，另一个有名称和值。我想查找另一个列表中的值并将结果写入 pref.Name。我知道我可以用 foreach 来做到这一点，但我认为在 LINQ 中有一种很好的方法可以做到这一点。想法？

public class Preference
    {
        public string Category { get; set; }
        public string Name { get; set; }
        public string ItemValue { get; set; }
        public int SortOrder { get; set; }
    }

public class SAPReadOnlyItem
    {
        public string Category { get; set; }
        public string Name { get; set; }
        public string ItemValue { get; set; }
    }

    List<Preference> preferences = getExistingUserPreferences(UserID, ddlCategory.SelectedValue); //this list is just keys
    List<SAPReadOnlyItem> sapReadOnlyItems = getSAPReadOnlyItems(ddlCategory.SelectedValue); //this list is names and keys

    //i want to look up the name from sapReadOnly using the ID from preferences and write it into preferences[n].Name

    //this works, but I want to write it into preferences[n].Name
    var foobar = (from sap in sapReadOnlyItems
                  join pref in preferences 
                  on sap.ItemValue equals pref.ItemValue
                  select new { asdf = sap.Name }).FirstOrDefault(); //instead of "select new" I want to write it into preferences[n].Name

Answer 1

我建议使用 Lambda foreach

preferences.ForEach(preference =>
                {
                    var sap = sapReadOnlyItems.FirstOrDefault(s => s.ItemValue = preference.ItemValue);
                    preference.Name = (sap != null) ? sap.Name : string.Empty;
                });