c# 如何比较和替换另一个列表<class>

Question

我在检查和存储旧数据中的新数据方面没有什么问题。我有一个 class 结构如下：

public class class1
{
    public List<Class2> class2List {get,set}
    ...
}
public class class2
    {
        public Class3 class3 {get,set}
        ...
    }
public class class3
    {
        public string name {get,set}
        public int index {get,set}
        ...
    }

我想创建一个方法，它将采用 class 2 输入并检查索引是否与旧的 class1 相同，如果是，我想存储它。我尝试做 sme linQ 来解决我的问题，但我不是专家，我有点卡住了...

public static void SaveNewDataOnlyIfSameIndex(class1 workingData, List<class2> newdata)
    {
        List<class3> LocalWorkingDataClass3 = new List<class3>();
        foreach(class2 item in workingData.class2)
            {
                LocalWorkingDataClass3.add(item.class3);
            }
        List<int> LocalWorkingDataIndex = new List<int>();
        foreach(class3 item2 in LocalWorkingDataClass3 )
            {
                LocalWorkingDataIndex.add(item2.index);
            }
        List<class3> LocalEqualClasstoReplace = new List<class3>();
        LocalEqualClasstoReplace = newdata.Where(File => LocalWorkingDataIndex.Equals(File.Index));
    }

Answer 1

我不太明白你需要什么，但你可以尝试使用 Linq 做这样的事情：

public static void SaveNewDataOnlyIfSameIndex(Class1 WorkingData, List<Class2> Newdata)
{
    List<int> LocalWorkingDataClass3Index = WorkingData.Class2List.Select(i => i.Class3.Index).ToList()
 
    List<Class3> LocalEqualClasstoReplace = new List<Class3>();
    LocalEqualClasstoReplace = newdata.Where(f => LocalWorkingDataClass3Index.Contains(f.Class3.Index));
}

Answer 2

Hi. First of all, I am not sure that i got your question.

    public class Class1
    {
        public List<Class2> class2List {get;set;}
    }
    public class Class2
    {
       public string name {get;set;}
       public int index {get;set;}
    }

    public void CompareAndReplace(ref Class1 orginalDataList, Class2 newData){
       var check=orginalDataList.class2List.FirstOrDefault(g=>g.index==newData.index);
       if(check!=null){
         check.name=newData.name;
       }
    }

   //example to use assuming to "orginalDataList" has some datas..
   
    CompareAndReplace(ref orginalDataList,new Class2{index=1,name="Hello"});

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