Question

如何重构下面的C＃代码

            foreach (var pref in ps._prefs) {
            for (int i = pref.Value.Count - 1; i >= 0; i--) {
                var val = pref.Value[i];

                // validate the field presence 
                try {
                    // this evaluates the relevent field, to make sure it is still presence. 
                    var prefCode = val.PreferenceCode;
                } catch (Exception e) {
                    Log.Warn(LogType.DataLayerService,
                        $"Referred field is no longer valid for FieldChooser for preference set. {ps.GetDisplayName()}. Still proceeding to delete the Preference Set.",
                        HttpContext.Current);
                    pref.Value.RemoveAt(i);
                }
            }
        }

我尝试过： ps._prefs.Values.ForEach(list => list.RemoveAll(p => p?.PreferenceCode is null));

Answer 1

也许它可以根据需要工作。

    ps._prefs.ForEach(pref => pref.Value.ForEach(val => 
         try {
                // this evaluates the relevent field, to make sure it is still presence. 
                var prefCode = val.PreferenceCode;
            } catch (Exception e) {
                Log.Warn(LogType.DataLayerService,
                    $"Referred field is no longer valid for FieldChooser for preference set. {ps.GetDisplayName()}. Still proceeding to delete the Preference Set.",
                    HttpContext.Current);
                pref.Value.Remove(val);
            }
));

Answer 2

我能得到的最接近的是

void Main()
{
    List<Test> prefs = new List<Test>(){ new Test (), new Test(){PreferenceCode = 1 }};

    var res = prefs.Select(x => {
        if (x?.PreferenceCode == null)
            Debug.Write(x);
        return x;
    }).Where(x => x?.PreferenceCode != null);

    res.Dump();
}

public class Test {
  public inb? PreferenceCode {get; set;}
}

使用RemoveAll

var res2 = prefs.RemoveAll(x => {
   if (x?.PreferenceCode == null){
     Debug.Write(x);
     return true;
   }

   return false;
});

res2.Dump();

Answer 3

尝试这样。。不是很确定它是否正常工作！！

foreach(var item in ps._prefs.Values)
   item.RemoveAll(i => i.Preference Code is null);

Answer 4

尝试以下LINQ：

ps._prefs.ForEach(perf => perf.Value = perf.Value.Where(v => v.PreferenceCode != null).ToList()))

在这里，我为Value的{{1}}字段分配了一个过滤列表，其中perf不为空。

谁能帮我使用Linq重构下面的C＃代码

4 个答案: