比较3个列表与不同类型数据的最佳方法

Question

I'm trying to find the best way to compare 3 lists in C# and then merge the result into one csv file. My code takes quite a lot of time to process my data and i want to improve this.

What I do at the moment is comparing 2 lists at a time using LINQ, saving the result for each comparison into a temporary list and then merge it before saving it as a csv file.

An example of one of my list compares:

foreach (RemedyAsset remedyAsset in RemedyAssetsList)
        {
            MIAsset tempMIAsset = null;

            tempMIAsset = MIAssetsList.FirstOrDefault(m => m.CIName.ToUpper() == remedyAsset.CIName.ToUpper());

            if (tempMIAsset == null)
            {
                TempAssets.Add(new TempAsset
                {
                    Asset = remedyAsset.CIName,
                    LastMiActivity = string.Empty,
                    RemedyStatus = remedyAsset.Status,
                    InMI = false,
                    InRemedy = true
                });
            }
            else
            {
                TempAssets.Add(new TempAsset
                {
                    Asset = remedyAsset.CIName,
                    LastMiActivity = tempMIAsset.LastActiveTime,
                    RemedyStatus = remedyAsset.Status,
                    InMI = true,
                    InRemedy = true
                });
            }
        }

My lists originates from 3 different IT systems(BMC Remedy, Active Directory, Checkpoint), which has one common variable: An asset number.

My lists look like this:

-(List1)RemedyReport: Asset number - Remedy status.
-(List2)ADReport: Asset number - last logon time - last password change.
-(List3)MIReport: Asset number - last server contact.

When I compare the lists, I also check if an asset number isn't present in a list and this also needs to be shown in the output csv file. I then needs to merge data from the lists where a matching asset number is present and the output will look like this:
Asset number - In Remedy - In MI - In AD - Last server contact - Last Logon - Last password change

What is the best way to compare 3 lists?
Is there any best practices when doing a compare of 3 or more lists?

This is my first post in here, please let me know if I've done anything wrong.

Solution based on Samar's suggestion
My adaption of Samar's suggestion, which fulfilled my needs. Performance improvement from 9 minutes to just under 2 minutes.

public void compare()
        {
            //Creating dummy data for testing
            List<C1> L1 = new List<C1>() { new C1() { ID = 1, classC1="test1" }, new C1() { ID = 4, classC1="test1" } };
            List<C2> L2 = new List<C2>() { new C2() { ID = 1, classC2="test2" }, new C2() { ID = 2, classC2="test2" } };
            List<C3> L3 = new List<C3>() { new C3() { ID = 1 }, new C3() { ID = 2, classC3="test3" }, new C3() { ID = 3, classC3="test3" } };

            //Creating new list which will contain all the objects without duplicates based on ID column
            List<C4> L4 = new List<C4>();

            //Firstly add all the objects from L1
            L4.AddRange(from l1 in L1 select new C4() { ID = l1.ID, classC1=l1.classC1 });

            //Add only those objects from L3 which are not part of L1
            L4.AddRange(from l22 in L2
                        where !(L4.Where(l44 => l44.ID == l22.ID)
                                .Select(l44 => { l44.classC2 = l22.classC2; return l44; }).Any(p => p.ID == l22.ID))
                        select new C4() { ID = l22.ID, classC2 = l22.classC2 });

            //Add only those objects from L3 which are not part of L1 and L2
            L4.AddRange(from l33 in L3
                        where !(L4.Where(l44 => l44.ID == l33.ID)
                                .Select(l44 => { l44.classC3 = l33.classC3; return l44; }).Any(p => p.ID == l33.ID))
                        select new C4() { ID = l33.ID, classC3 = l33.classC3 });

            //L4 will now contain all IDs without duplicates
        }

        class C1
        {
            public int ID { get; set; }
            public string classC1 { get; set; }

            //will contain other properties
        }

        class C2
        {
            public int ID { get; set; }
            public string classC2 { get; set; }

            //will contain other properties
        }

        class C3
        {
            public int ID { get; set; }
            public string classC3 { get; set; }

            //will contain other properties
        }

        class C4
        {
            public int ID { get; set; }
            public string classC1 { get; set; }
            public string classC2 { get; set; }
            public string classC3 { get; set; }

            //will contain other properties or maybe a combination of all the properties of C1, C2 and C3
        }

Answer 1

I am not able to understand your class structure so I will try to answer your question in a more generic manner.

Firstly let me understand what you exactly need.

Say you have 3 lists with 3 different classes in them. So you have lists L1, L2 and L3 and within them are classes C1, C2 and C3 respectively.

You need a single list say L4 with another (or one of the above?) class say C4 and this list should not contain duplicates based on some common property in all the 3 classes.

My take to this problem is the following code. I am not very sure if this is efficient but it sure works. It is also not generic ie applicable to any number of list with any set of classes implementing a certain interface. Try it out and let me know if, performance wise, it is creating a problem or in any other way for that matter.

I hope this helps.

Regards,

Samar

    private void btnCompare_Click(object sender, EventArgs e)
    {
        //Creating dummy data for testing
        List<C1> L1 = new List<C1>() { new C1() { ID = 1 }, new C1() { ID = 4 } };
        List<C2> L2 = new List<C2>() { new C2() { ID = 1 }, new C2() { ID = 2 } };
        List<C3> L3 = new List<C3>() { new C3() { ID = 1 }, new C3() { ID = 2 }, new C3() { ID = 3 } };

        //Creating new list which will contain all the objects without duplicates based on ID column
        List<C4> L4 = new List<C4>();

        //Firstly add all the objects from L1
        L4.AddRange(from l1 in L1 select new C4() { ID = l1.ID });

        //Add only those objects from L2 which are not part of L1
        L4.AddRange(from l22 in L2
                    where !(from l4 in L4 join l2 in L2 on l4.ID equals l2.ID select new { ID = l4.ID }).Any(p => p.ID == l22.ID) 
                    select new C4() { ID = l22.ID });

        //Add only those objects from L3 which are not part of L1 and L2
        L4.AddRange(from l33 in L3
                    where !(from l4 in L4 join l3 in L3 on l4.ID equals l3.ID select new { ID = l4.ID }).Any(p => p.ID == l33.ID)
                    select new C4() { ID = l33.ID });

        //L4 will now contain all IDs without duplicates
    }

    class C1
    {
        public int ID { get; set; }

        //will contain other properties
    }

    class C2
    {
        public int ID { get; set; }

        //will contain other properties
    }

    class C3
    {
        public int ID { get; set; }

        //will contain other properties
    }

    class C4
    {
        public int ID { get; set; }

        //will contain other properties or maybe a combination of all the properties of C1, C2 and C3
    }