在C＃中的List中获取并设置对象的值

Question

I have a list of objects , and I need to search if a value exists in the list, if it does, I need to set one of the properties of the object found to another value, is it possible to do this without searching the List twice? (Once to check if the object exists in the list and once to set its value)

For example:

class myObject
{
   public string FieldNumber {get;set;}
   public string FieldValue  {get;set;}
}

var myValues = new List<myObject>();
myValues.Add(new myObject{ FieldNumber = "100A"});
myValues.Add(new myObject{ FieldNumber = "100B"});

var allValues = new List<myObject>();
allValues.Add(new myObject{ FieldNumber = "200A", FieldValue = "3"});
allValues.Add(new myObject{ FieldNumber = "100B", FieldValue = "C"});

foreach(var obj in allValues)
{
    GetAndSetField(myValues, obj.FieldNumber, obj.FieldValue);
}

void GetAndSetField(List<myObject> list, string fieldNumber, string fieldValue)
{
    var tempField = list.FirstOrDefault(x => x.FieldNumber.Equals(fieldNumber));
    if(tempField != null)
        list.FirstOrDefault(x => x.FieldNumber.Equals(fieldNumber)).FieldValue = fieldValue;
}

Is it possible to change the code in the GetAndSetField method so that it doesn't search the list twice if the object is found? Or maybe I'm doing this completely wrong and there's an easier way...

Answer 1

You're already reading out tempField . Just use it:

void GetAndSetField(List<myObject> list, string fieldNumber, string fieldValue)
{
    var tempField = list.FirstOrDefault(x => x.FieldNumber.Equals(fieldNumber));
    if (tempField != null)
        tempField.FieldValue = fieldValue;
}