Question 87561 in ASP.NET Question posted in
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Compare two list for differences – DateTime & String – Asp.net

Sorry but there is no code for this question… I hope thats ok.

So, I have a list of objects with two properties, DateTime and String.

As a matter of fact, DateTime is just date (insertDate), for example 2022-02-04T00:00:00+01:00.
String is of course some text, a lot of text 🙂

I have to compare the list with these two properties with another list of identical structure.

To be more clear, those are the data returned by the API, so I have to compare is there any differences between these two lists.

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2

Answers


  1. 0

    Do it like this (it will compare two lists based on element index , so
    if your lists are unsorted you must sort them and then use these codes) :

    public class YourClass
{
    public DateTime DateTime { get; set; }
    public string String { get; set; }
}

public class Program
{
    static List<YourClass> list1 = new List<YourClass>
    {
        new YourClass { DateTime = DateTime.MinValue, String = "str1"},
        new YourClass { DateTime = DateTime.Now.AddDays(1), String = "str2"},
        new YourClass { DateTime = DateTime.Now.AddDays(2), String = "str3"}
    };

    static List<YourClass> list2 = new List<YourClass>
    {
        new YourClass { DateTime = DateTime.MinValue, String = "str1"},
        new YourClass { DateTime = DateTime.Now.AddDays(-1), String = "2str"},
        new YourClass { DateTime = DateTime.Now.AddDays(-2), String = "3str"}
    };

    static void Main(string[] args)
    {
        //a list of integer for storing different elements indexes
        var differentElementsIndexes = new List<int>();

        //check difference of these two list using for loop
        for (int i = 0; i < list1.Count; i++)
        {
            if (list1.ElementAt(i).DateTime != list2.ElementAt(i).DateTime || list1.ElementAt(i).String != list2.ElementAt(i).String)
                differentElementsIndexes.Add(i);
        }
    }
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  2. 0

    You can use a CustomComparator:

    Given your base class for both lists:

    public class BaseClass 
{ 
    public DateTime date { get; set; }
    public string anyString { get; set; }
}

    Define the custom comparer for it

    public class BaseClassComparer : IEqualityComparer<BaseClass>
{
    public bool Equals(BaseClass item1, BaseClass item2)
    {
        //Check whether the compared objects reference the same data.
        if (Object.ReferenceEquals(item1, item2)) return true;

        //Check whether any of the compared objects is null.
        if (Object.ReferenceEquals(item1, null) || Object.ReferenceEquals(item2, null))
        return false;

        //Check whether the required fields' properties are equal.
        return (item1.date == item2.date) && (item1.anyString == item2.anyString);
    }

    public int GetHashCode(BaseClass item)
    {
        //Check whether the object is null
        if (Object.ReferenceEquals(item, null)) return 0;

        //Get hash code for the Date field if it is not null.
        int hashItemDate = item.date == null ? 0 : item.date.GetHashCode();

        //Get hash code for the string field.
        int hashItemString = item.anyString.GetHashCode();

        //Calculate the hash code for the item.
        return hashItemDate ^ hashItemString;
    }
}

    Then you can use it as follows:

            List<BaseClass> class1 = new List<BaseClass>();
        List<BaseClass> class2 = new List<BaseClass>();
        BaseClass item1 = new BaseClass() {date = DateTime.Now, anyString = "Hello"};
        class1.Add(item1);
        class2.Add(item1); //<-Equal till here
        //class1.Add(item1); //<-uncomment for false
        bool result = class1.SequenceEqual(class2, new BaseClassComparer());
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