Linq Except Comparer

InvariantCulture and InvariantCultureIgnoreCase are generally not to be used except in very limited circumstances, because ordinal comparisons are more efficient. NET của hàng đợi ưu tiên hoặc cấu trúc dữ liệu heap. Get all the elements from the first array except for the elements from the second array. 5 and later. For example if you wanted add few more it would look like:. But compare some of those actions to the amount of memory that would have to be allocated in a none linq setting. In this case. C#のLINQの関数であるExcept()の使い方についてです。 配列やリストの要素同士を比べて、差集合のシーケンスを作成することが出来ます。. Solving the Detached Many-to-Many Problem with the Entity Framework except that the object’s State is reset toModified between operations. It’s interesting to see Microsoft has closed the ticket as “won’t fix”. Linq to Dictionary with I Equality Comparer in C# This interface recognize the implementation of customized equality comparison for collections. Some of these methods are just shortcuts for common Linq operations (e. It manages the relational data as an object. We will extend our. You could use Reflection which will go through each public property of the class (which will be very generic) and compare them, but that will be slower. I was trying to pick items with Except Comparer from the list. We can query any type of object that implements the IEnumerable interface or IEnumerable, which is of generic type. Except( second, // required comparer // optional ) Parameter first Eine Sequenz, dessen Elemente nicht auch in second enthalten sind. Using INTERSECT with LINQ to XML leave a comment » In terms of hands-on coding (not general awareness) I'm a bit of a newbie to the world of LINQ actually, having only dabbled with a little LINQ to XML in MockingBird and even there I wasnt too impressed with it in the area of XPath queries. Xml (LINQ to XML) to allow relational and XML data to gain the benefits of language-integrated query. Microsoft's query language is fully integrated and offers easy data access from in-memory objects, databases, XML documents and many more. LINQ by Example 4: Query Expression Syntax LINQ by Example 5: LINQ to XML Querying The following methods have overloads than can use an IEqualityComparer: Contains, Distinct, Except, GroupBy x4, GroupJoin, Intersect, Join, SequenceEqual, ToDictionary x2, ToLookup x2, Union (x4 means that GroupBy has four overloads that take a comparer. LINQ isn't designed to save the computer time. LINQ 图解 Linq中的Select——投影 Linq学习资源 Expert C# 5. Of course you can but I think these were added to prevent you from writing it the way you intended (like in natural English you would be saying order by X then by Y then by Z). It will only return elements in the first sequence that don't appear in the second. How to fix this performance issue but still maintaining the sorting requirements?. LINQ (Language-Integrated Query) – Many examples from MSDN; Linq filtering (in clause) LINQ Group by MAX Date Query; LINQ JOINS (inner join, left outer join, right outer join, full outer join) LINQ to DataSet; LINQ to Objects; LINQ to SQL; Linq to XML; Linq XML. As an alternative, you may want to consider using the. LINQ - 'Where' with 'First' instead of FirstOrDefault. Distinct method is that it has no overload allowing you to give a lambda expression to specify a particular property to perform the distinction, you have to give an IEqualityComparer. WriteLine(product. That is, you can make your own definition of equality, and specify that this definition be used with a collection type that accepts the IEquality Comparer interface. These short examples demonstrate how to. If it is your first time when you hear about Azure IoT Hub, than you should know that Azure IoT Hub is a powerfull serviced offered by Azure that can connect, manage and monitor your devices. In a recent tip on Language INtegrated Query (LINQ), you have described how it can be used as a query language extension to both VB. save Save LINQ C# Microsoft Docs. Why Enumerable. LINQ providers can give LINQ access to data inside SQL Server, inside XML, and more. Ultimately, I want to compare two sets of entities and see whether they match. This is the LINQ extension method that subtracts elements from a collection. Language Integrated Query (LINQ, pronounced "link" [citation needed]) is a Microsoft. This extension method is found in the System. How can we use LINQ to SQL in. One of the extension methods in the System. NET Datasets,. Pro LINQ: Language Integrated Query in C# 2008 Did you notice how I parsed the XML data into an object of type XElement? Nowhere did I create an XmlDocument. As we discussed it return elements only from first collection which are not exists in second collection. Integer Performance Comparison for C++, C#, Delphi. Hey Guys! We are pleased to announce a technical preview of the 1. Some of these methods are just shortcuts for common Linq operations (e. In this example the default comparer is being used and the comparison is case-sensitive, so in the output we see country USA 2 times. To mitigate this problem, LINQ introduces the Let clause. Data; using System. One of the things that annoys me with the IEnumerable. That is why I created a ParameterParser class that results a list of Parameter objects that can be queried with Linq. NET Framework version 3. Except 方法可以用在从一个集合中删除一个项集合. Sample Data Object To test examples, you need to include the in your project. At the same time, the value of a separate implementation than CPython is to make available the. CompareTo and IComparable are often faster than LINQ and the orderby clause. Queryable 接口的扩展方法,并且都是延迟加载方法。. You could use Reflection which will go through each public property of the class (which will be very generic) and compare them, but that will be slower. Pro LINQ: Language Integrated Query in C# 2008 Did you notice how I parsed the XML data into an object of type XElement? Nowhere did I create an XmlDocument. a) you have to define comparer var methodsToDelete = dbMethods. The "Except" operator produces the set difference between two sequences. These two additions were really meant for each other. Rather than performing a join, you access the orders by using dot notation:. I examined the methods of System. SafeHandles. Name & " " & product. Search this site. Text; // Include Silverlight's managed resources #if SILVERLIGHT using System. Net Query syntax. The hardware specs: Intel i7-6700 CPU (3. You can find entire list of set operators here. Is it possible two make single linq expression to get result. You also don't need to do a initial select on resourceBaseSet. WriteLine("Except creates a single sequence from numbers1 and removes the duplicates found in numbers2:") For Each number As Integer In result Debug. This post is focusing on Device Twins that are available on Azure IoT Hub. Comparison of LINQ support. Except(moduleMethods, new CustomComparer()); b) i suggest to use generic comparer IEqualityComparer c) first Except checks if hashcode is equal and then uses Equal method Regards Max. Net Runtime Library for Delphi (CNClrLibrary). Today I needed to compare two generic lists… SequenceEqual() to the rescue. Both are object-oriented , and designed with semi- interpretation or runtime just-in-time compilation , and both are curly brace languages , like C and C++. Except is one of the useful extension methods within the System. Your task is to merge two lists of objects. Net A function named GetData is used to fetch the records from the Customers table and return them in the form of a DataTable. It’s interesting to see Microsoft has closed the ticket as “won’t fix”. html": { "href": "api/Microsoft. Is it possible two make single linq expression to get result. The same source code is the foundation for this compilation, but with all queries converted to Lambda-style LINQ queries. Implementing IEqualityComparer on classes can sometimes be unwanted to just make the computations work, therefore a generic implementation would be nice to invoke when performing the LINQ expression. LINQ to XML은 XmlReader를 기반으로 구현되었으며 두 기술은 밀접하게 통합되어 있다. Collections. It is a concept which integrates a query language by offering a consistent model for working with data across various kinds of data sources and formats; you use the same basic coding patterns to query and transform data in XML documents, SQL databases, ADO. I want to take this thought a step further, and as implied by the post title, do a group by. This operator returns distinct elements from a given collection. NET programming model that adds querying capabilities to. LINQ之LINQ to Objects(上) LINQ概述 LINQ,语言集成查询(Language Integrated Query),它允许使用C#或VB代码以查询数据库相同的方式来操作不同的数据源. For example, a Customerobject contains a collection of Order objects. Comparison of LINQ support. Debugged through a legacy C# LINQ query, and this query contained a Distinct operator. Using Grouping instead of Distinct in Entity Framework to Optimize Performance On a number of pages on this web site I display a list of articles. Rather than performing a join, you access the orders by using dot notation:. The extension methods return a new element, that contains nothing - effectively a null element. LINQ 101 Samples - Lambda Style This compilation is based on the 101 LINQ Samples by Microsoft. Hi, I have two dictionaries collection lets say A and B, I want to except dictionary B from A based on the key value(remove all items in the A that heir keys found in. LINQ Except Method in C# with Examples. But compare some of those actions to the amount of memory that would have to be allocated in a none linq setting. Dim except = fruits1. NET programming languages. Embed Embed this gist in your website. When doing a traditional join in SQL (or in LINQ) it doesn't matter what entity you start with, but when using navigation properties it does matter. LINQ brings the ability to query data to. >> What is "Best Practice" – using the strongly-typed generic versions of LINQ methods or the non-generic (e. Unfortunately though it doesn't work in. Comparison of LINQ support. cs source code in C#. In general, if you see that a LINQ method has an overload that accepts the IEqualityComparer parameter, it probably means that to use it for your own data types you need to either implement IEquatable in your class or create your own equality comparer. 5 introduced a handy little new method Comparer. In this case. OrderedEnumerator. A LINQ provider is a gateway for LINQ to act upon data that is not inside a queryable type. Using these commands is pretty straight forward, so we'll give an example which illustrates all of them. Except is one of the useful extension methods within the System. 今回は、Except拡張メソッドについてです。 Except拡張メソッドは、差集合を生成します。 つまり、2つのシーケンスの内、片方だけに存在している要素のみが抽出されます。. One approach to using those methods would be to make your own equality comparer. An archive of the CodePlex open source hosting site. Suppose you have two lists, one old and one new, and you are looking to compare the differences between them. For example, we have two collections A = { 1, 2, 3 } and B = { 3, 4, 5 }. NET Framework. I couldn't just compare the two tables in the SQLServer Database because the itemNum was added to the dtPhysical dataTable after the initial data Fill. I hope this article gives you a very. How to find unique/duplicate values between two columns in excel? For example, I have two columns of different length filled with student names, and now I want to compare these two columns to select all values in column A but not in column B, and select all values in column B but not in column A. WriteLine("Except creates a single sequence from numbers1 and removes the duplicates found in numbers2:") For Each number As Integer In result Debug. Now we got a clear picture about Union operator in linq, it's used to merge the two collections and returns distinct elements from those collection sand we need to implment the IEqualitycomparer while we work with huge amounts of data. LINQ by Example 4: Query Expression Syntax LINQ by Example 5: LINQ to XML Querying The following methods have overloads than can use an IEqualityComparer: Contains, Distinct, Except, GroupBy x4, GroupJoin, Intersect, Join, SequenceEqual, ToDictionary x2, ToLookup x2, Union (x4 means that GroupBy has four overloads that take a comparer. NET Framework version 3. You can find entire list of set operators here. I tried using LINQ Except. As we discussed it return elements only from first collection which are not exists in second collection. This method uses the equality comparer which was set in the constructor or the dictionary to determine equality for the key. NET languages, and some of the languages have provided extensions to make its use even more intuitive. This is the response that I wrote and thought I would surface it in my blog: Besides that Linq to SQL is only for SQL () one of the big differences is that the EDM is more flexible and more loosely. Command line parsing in C# is (static void Main(args []string) is very limited. You also don't need to do a initial select on resourceBaseSet. Linq to Dictionary with I Equality Comparer in C# This interface recognize the implementation of customized equality comparison for collections. Need private packages and team management tools? Check out npm Orgs. NET Framework. Collections. Here are the sample List for demonstration purposes. Code) Next ' This code produces the following output: ' ' orange 4 ' lemon 12 Remarks. Linq namespace) generic type can be used. And you'll have comparable amount of memory usage. Generic; using System. Comparable is an interface that has to be implemented by a custom collection elements in order to work with linq. The implementation of the ContactEmailComparer is pretty trivial, but it does seem like a lot of work just to get a distinct list of email addresses. cs source code in C#. Sorting is a feature of any good framework dealing with collections. Except(t)), although I also just found out that LLBLGen doesn't support Union, so I was trying other approaches. Linq; namespace AbundantCode { internal class Program { //How to Merge two lists using LINQ's […]. As a relatively new user of. Implement an IEqualityComparer as a nested class of ResourceBase and then the Except clause is a 1 liner. Except In this video we will discuss Distinct operator. Net Runtime Library for Delphi (CNClrLibrary). 比如, 我有个由 {1,2,3,4,5,6,7} 组成的集合 A 和由 {1,2,3} 组成的集合 B,A 除了 (except) B 将会输出 {4,5,6,7}, 下面的程序说明了 Except 的用法. public static IEnumerable Except(this IEnumerable first, IEnumerable second, IEqualityComparer comparer); 좋아요 공감 공유하기. So I've re-written a query that would allow you to compare a list of AFElements by Name with a list of strings, and produce a results list containing only Elements from MainList that are. Below is a sample code snippet demonstrating in simple steps on how to merge two lists using LINQ's Union extension method in C#? C program to compare 2 numbers. /// Unfortunately, since TKey may be a value type, we cannot test whether the key is null /// using the user-specified equality comparer. Select())?. Batches: Better SQL+RPC+WS Better client access to remote data and services in any programming language. Except(moduleMethods);. specify default value for FirstOrDefault, specify comparer for Max). With the above code (all can be found in github), all compiled to RELEASE version, and TickCount is recorded on Windows 10. Except(numbers2) Select n Debug. It seems that you want PRDSProjectColumns to be a value type. This extension method is found in the System. The extension methods return a new element, that contains nothing - effectively a null element. Introduction to LINQ. Sample Data Object To test examples, you need to include the in your project. How do you compare two sequences using LINQ? The answer is by using the Enumerable. Working that out helped to show that my EXCEPT was failing more on the data type than the actual values it was comparing against. Compare IEnumerable collection of custom objects in Linq To use Linq : Except, Intersect, etc. Following is the pictorial representation of LINQ Except method. The resulting collection should be without duplicates, based on a certain property on the objects. Hey Guys! We are pleased to announce a technical preview of the 1. Starting, here is an order by % 2 giving us a list of. Create to aid the creation of bespoke comparers, which is great because it means that you don't have to define a new Comparer class when it is going to be needed once. The hardware specs: Intel i7-6700 CPU (3. Now see the result with Iequalitycomparer. Tunnel Bag Medium Roll Top 25L Black LinQ 32. Tags: Distinct query operator , LINQ using VB. Example 1: Return distinct country names. 101 LINQ Samples Learn how to use LINQ in your applications with these code samples, covering the entire range of LINQ functionality and demonstrating LINQ with SQL, DataSets, and XML. Comparable is an interface that has to be implemented by a custom collection elements in order to work with linq. LINQ Intersect operator is used to find common elements between two sequences (collections). Collections. la liste des résultats ne contiendra que des éléments modifiés. To fix this problem, use the AsParallel() extension method to convert the right data source to System. NET, WEB DEVELOPMENT, WebForms, LINQ This space is for rent. Please read our previous article where we discussed the LINQ Except() Method with examples. I thought of using the implement IEqualityComparer but I am not sure how to implement the GetHashCode it for two diffrent type of classes. In this case. For a more detailed comparison of the platforms, please see Comparison of the Java and. Linq provides the IEnumerable. As we discussed it return elements only from first collection which are not exists in second collection. In this article, I am going to discuss the LINQ Except Method in C# using examples. For example, the same is true for the Contains, Except, Intersect, and Union methods. Sorting is a feature of any good framework dealing with collections. For both LINQ to SQL and Entity Framework, I used the visual designer tools to include only the Customers table in the model. Compare two List using LINQ lstNew = lstOne. The following figure shows how each set operators works on the collections: LINQ Set operators. specify default value for FirstOrDefault, specify comparer for Max). 5 introduced a handy little new method Comparer. LINQ to XML은 XmlReader를 기반으로 구현되었으며 두 기술은 밀접하게 통합되어 있다. Linq to Dictionary with I Equality Comparer in C# This interface recognize the implementation of customized equality comparison for collections. DataTable Comparison Using LINQ Except, Intersect and Union This article describes you how to compare DataTables to get matched, unmatched, combine list of all rows in both tables. Second, if re-writing the query is required, you must coax LINQ to SQL into generating the SQL syntax you're after. So either combining the above query into single query or any other way to impliment custom Comparer for two diffrent Type of classes. In case you’re wondering, it’s still not possible to define anonymous implementation of interfaces in …. LINQ – ‘Where’ with ‘First’ instead of FirstOrDefault. /// Unfortunately, since TKey may be a value type, we cannot test whether the key is null /// using the user-specified equality comparer. If comparer is null, the default equality comparer, Default, is used to compare values. Contact me at vmsdurano at gmail dot com. Search this site. In this case. The extension methods return a new element, that contains nothing - effectively a null element. -----Solutions----- You can use this code for comparing two dates using linq i. Select())?. PreprocessorLoader. 0 and newer and defines a set of proprietary. DataTable Comparison Using LINQ Except, Intersect and Union This article describes you how to compare DataTables to get matched, unmatched, combine list of all rows in both tables. SequenceEqual() compares the source and target sequences elements, by using the default equality comparer for their type, and returns a Boolean. LINQ operators generally use lambda expressions to control their processing and output. Also, I live and work in Southern Oregon. Entity SQL, as an alternative to LINQ, querying the Entity Framework. NET framework in C#. However it is returning list which is present in strList1. Comparing array elements in c#. Except(fruits2, New ProductComparer()) For Each product In except Console. LINQ allows for simple modification, transformation, and combination of various IEnumerables using a query-like or functional syntax. //Use MyComparer to compare all members of type string except members. Except(Of TSource) Method (IEnumerable(Of TSource), IEnumerable(Of TSource)) Produces the set difference of two sequences by using the default equality comparer to compare values. Enumerable class in the System. A generic IEqualityComparer of T written in C# When working with LINQ, often one has to pass in an IEqualityComparer of the class(es) being used. Except we will see an example of how to do a Left Outer Join in LINQ and C#. f1 if a < b { return -1 } else if a > b { return 1 } return 0 }. OverflowException saying that “Arithmetic operation resulted in an overflow”. For a more detailed comparison of the platforms, please see Comparison of the Java and. NET Framework 3. Tôi đang tìm kiếm một triển khai. Iterator:枚举器 如果你正在创建一个表现和行为都类似于集合的类,允许类的用户使用foreach语句对集合中的成员进行枚举将会是很方便的。. LINQ brings the ability to query data to. The diary of a. Suppose you have two lists, one old and one new, and you are looking to compare the differences between them. This is because LINQ to Entities can’t translate the comparer to the source database. LINQ to XML과 다른 XML 기술 비교 LINQ to XML, XmlReader, XSLT, MSXML 및 XmlLite와 같은 XML 기술을비교. Improving LINQ Except and Intersect by using a lambda expression for custom comparison August 14, 2009 Akshay Luther 2 Comments I was recently doing some work where I had to use Except and Insersect, but with some custom comparison logic. I assume that you are familiar with LINQ. 介绍LINQ之前先介绍一下枚举器. It seems that you want PRDSProjectColumns to be a value type. As you know, Inner join returns only those records or rows that match or exists in both the tables. InvariantCulture and InvariantCultureIgnoreCase are generally not to be used except in very limited circumstances, because ordinal comparisons are more efficient. The expected behavior is that all the elements in source1 are returned except for those that are also in source2, and comparer is used to compare values. After doing quick search on google found the below extension method which can be used in such scenario. Unfortunately though it doesn't work in. However, if you have custom objects in the two arrays then the default object reference comparer won't be enough:. This article describes a generic comparer, driven by delegates, designed for use in queries. NET Framework component that adds native data querying capabilities to. NET framework version 3. Along the way, I learned a fact about some LINQ extensions and a bad practice I've been so oblivious after all these years. Ø 前言 LINQ to SQL 中需要对两个或多个数据集进行操作,比如,合并、取交集等,主要使用下面四个方法,这四个方法都是 System. In LINQ, Except method or operator is used to return only the elements from first collection which are not present in second collection. You can find entire list of set operators here. Net , C# , Hints and Tips on January 22, 2014 by Craig Removing items from one list that exist in another seems to be one of a developer's life's constants so I thought I'd write a short post showing how to carry out this task with the least amount of lines of code. Except() Might Not Work the Way You Might Expect August 8, 2011. Can I use a lambda expression to provide the equality function, like when I use Where or other LINQ functions? If I can't, is there an alternative?. But compare some of those actions to the amount of memory that would have to be allocated in a none linq setting. Posted by Jonas Elfström Thu, 18 Oct 2012 21:28:00 GMT. LINQ Except operator comes under Set operators category in LINQ. The expected behavior is that all the elements in source1 are returned except for those that are also in source2, and comparer is used to compare values. Is it possible two make single linq expression to get result. Collections. Enumerable class in the System. How to find unique/duplicate values between two columns in excel? For example, I have two columns of different length filled with student names, and now I want to compare these two columns to select all values in column A but not in column B, and select all values in column B but not in column A. NET languages, originally released as a major part of. Reflection; using System. When it comes to querying databases, LINQ is in most cases a significantly more productive querying language than SQL. LINQ (Language-Integrated Query) – Many examples from MSDN; Linq filtering (in clause) LINQ Group by MAX Date Query; LINQ JOINS (inner join, left outer join, right outer join, full outer join) LINQ to DataSet; LINQ to Objects; LINQ to SQL; Linq to XML; Linq XML. Collections; using System. I was correct, but the overload takes an IEqualityComparer. >> What is "Best Practice" – using the strongly-typed generic versions of LINQ methods or the non-generic (e. I made extension methods for element (eg. It's coding made sexy. Provides a general introduction to the kinds of applications that you can write and the kinds of problems that you can solve with LINQ queries. Collections; using System. Using these commands is pretty straight forward, so we'll give an example which illustrates all of them. For the table that has related records (in this example, the Order Details table), double-click each field that is joined to the first table, except for the field that you chose on the third page of the wizard (in this case, the Product ID field). When working with LINQ to DataSet, you should also keep in mind how the LINQ set query operators (Union, Distinct, Intersection, Except) work. NET Here we will see that how to removes duplicate elements from a sequence in Linq using VB. In the unit test above, two lists containing the topmost FIFA ranking country teams in soccer in the world are being used in a LINQ Except expression, where the generic LambdaComparer class is being used. Instances of this class could be used with Language-Integrated Query (LINQ) standard query operators, rather than creating custom comparer classes for each data type that you worked with. Enumerable class in the System. As you know, Inner join returns only those records or rows that match or exists in both the tables. Need private packages and team management tools? Check out npm Orgs. Except(IEnumerable second, IEqualityComparer, if the item is found; otherwise, a negative number that is the bitwise complement of the index of the next element that is larger than item or, if. For example, the same is true for the Contains, Except, Intersect, and Union methods. C#のLINQの関数であるExcept()の使い方についてです。 配列やリストの要素同士を比べて、差集合のシーケンスを作成することが出来ます。. LINQ providers can give LINQ access to data inside SQL Server, inside XML, and more. Remove Matching Items from a List Using LINQ and Lambda posted in. You also don't need to do a initial select on resourceBaseSet. Except(numbers2) Select n Debug. The interface can be implemented to allow customised comparison of values and objects. Generic; using System. LINQ 图解 Linq中的Select——投影 Linq学习资源 Expert C# 5. To show how it works, here is some sample code:. Intersect opertor comes under Set operators category in LINQ Query operators. Except In this video we will discuss Distinct operator. -----Solutions----- You can use this code for comparing two dates using linq i. C#のLINQの関数であるExcept()の使い方についてです。 配列やリストの要素同士を比べて、差集合のシーケンスを作成することが出来ます。. LINQ brings the ability to query data to. That is why I created a ParameterParser class that results a list of Parameter objects that can be queried with Linq. Generic; using System. Or is ther. Unfortunately though it doesn't work in. Get all the elements from the first array except for the elements from the second array. This banner text can have markup. I want to take this thought a step further, and as implied by the post title, do a group by. LINQ operators generally use lambda expressions to control their processing and output. Except subtracts elements from a collection. NET languages, and some of the languages have provided extensions to make its use even more intuitive. Private Shared Sub Sample_Except_Linq() Dim numbers1 As Integer() = {1, 2, 3} Dim numbers2 As Integer() = {3, 4, 5} Dim result = From n In numbers1. net Sometimes it's very useful to compare two DataTables and return the different records to a third DataTable. The expected behavior is that all the elements in source1 are returned except for those that are also in source2, and comparer is used to compare values. Iterator:枚举器 如果你正在创建一个表现和行为都类似于集合的类,允许类的用户使用foreach语句对集合中的成员进行枚举将会是很方便的。. For example: non-linq. Recientemente comencé a usar LINQ bastante, y realmente no he visto ninguna mención de complejidad en tiempo de ejecución para ninguno de los métodos LINQ. Except and Intersect operation between two DataTable using Linq. Private Shared Sub Sample_Except_Linq() Dim numbers1 As Integer() = {1, 2, 3} Dim numbers2 As Integer() = {3, 4, 5} Dim result = From n In numbers1. In general, if you see that a LINQ method has an overload that accepts the IEqualityComparer parameter, it probably means that to use it for your own data types you need to either implement IEquatable in your class or create your own equality comparer. But it seems that the syntax is a real struggle. The fact that the reviewer of the ticket thought you were talking about LINQ to SQL just painted a picture of the person not even caring to check this page (as linked from the ticket). This IEqualityComparer interface is widley used in Linq. List[Employee] list = new List[Employee](). Enumerable. Append, IsNullOrEmpty), or improvements to existing Linq methods (e. (except by using the I just cant write this thing with my own Comparer which i would really wanted to learn. A more universal solution is to write a generic class where you can tell it which property of your objects to compare on. Provides a general introduction to the kinds of applications that you can write and the kinds of problems that you can solve with LINQ queries. Except(other, comparer);. The Except operator is Not Supported in C# & VB.