It contains well written, well thought and well explained computer science and programming articles, quizzes and practice/competitive programming/company interview Questions. Syntax. rev2023.3.3.43278. After you become more familiar with lambdas, you will find that they are a powerful and flexible tool in your LINQ toolbox. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. You can perform the where separately from the main query: var result = from dm in datacontext.Trk select dm; if (intval == 0) { result = result.Where (dm => dm.ID == 0); } else { result = result.Where (dm => dm.ID != 0); } if (result.Any ()) { // do something } Share Follow answered Jan 20, 2012 at 22:52 Chris Dunaway 10.8k 4 35 47 { toprint = "Below"; } The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. Connect and share knowledge within a single location that is structured and easy to search. These operators are also used for implementing paging. So you have two results, one in if block and one in else block which are different and are not visible outside their blocks. Status = (Deals.Count() == 0 ? Any time you want to do a side-effect per element (such as logging), breaking out the lambda into a statement body makes it easy to reason about. "We, who've been connected by blood to Prussia's throne and people since Dppel", Movie with vikings/warriors fighting an alien that looks like a wolf with tentacles. LINQ simplifies the queries by offering a consistent model for working with data across various kinds of sources and formats. For example, you might use them like this: var query = items.Where( x => x. SomeProperty > someValue); query = query.If( searchByOtherProperty, q => q.Where( x => x. OtherProperty == otherValue); @Tudor, I can't understand the performance problem. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Not the answer you're looking for? Php having trouble with the if, else statement . If that is not what you are doing, show some sample data. s.StudentID == StudentUserID : (s.TutorUserID == TutorUserID && s.StudentID == StudentUserID)), where s.TutorUserID == TutorUserID && s.StudentID == StudentUserID. For example, you must use a method call to express a query that retrieves the number of elements that match a specified condition. To get started using LINQ, you do not have to use lambdas extensively. Here are some key differences between if/else and switch-case: if/else can handle multiple conditions in a single statement, whereas switch-case can only handle a single variable or expression. A. SQL injection has been a significant risk for traditional SQL queries formed by concatenating user input. Also you need paranthesis around the condition in the second if statement. To support grouping, the LINQ provides the group.by operation. s.StudentID == StudentUserID : s.TutorUserID == TutorUserID), where (ISSTUDENT == true ? However, if you invoke the IntelliSense completion list in the Visual Studio IDE, you will see not only a Where method, but many other methods such as Select, SelectMany, Join, and Orderby. this is excellent and should be shared all over the web, only good answer for any conditional where statement. email is in use. Is this "correct". The conditional operator (? But my case is, if conditionvariable > 0. Using a dynamic LINQ library we can do the following, Select statement at runtime (pass select statement as string) Where condition at runtime (pass where statement as string) Here in this article we will first see what happens without using a dynamic LINQ library if we are passing a SELECT Statement at runtime. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. I think you want to make a || between conditions and table2 will be queried based on p.CondtionVariable. Wrong answer. I need to ignorefilter condition if line id is 0 and empty. But as Kelsey pointed out this would work too -. The content posted here is free for public and is the content of its poster. spelling and grammar. Can I tell police to wait and call a lawyer when served with a search warrant? Acidity of alcohols and basicity of amines, Theoretically Correct vs Practical Notation. The "return value" is just the expression result. In Stored Procedure we use if Cond. Extensions methods "extend" an existing type; they can be called as if they were instance methods on the type. Using LINQ Method Syntax, it is a little difficult to write the join query when joining more than two data sources. Why do many companies reject expired SSL certificates as bugs in bug bounties? value of a Boolean expression. Check out this New 2024 Evo Red LYNX RAVE RE 850 E-TEC Ice Ripper XT 1.25 M.S. The following code snippet shows how to write the query to fetch data from three data sources using the LINQ Method syntax. What's the difference between a power rail and a signal line? What if p.ConditionVariable != 0? How to show that an expression of a finite type must be one of the finitely many possible values? string toprint = string.Empty; Use an inline annonymous function instead of a single line expression so that you can use a normal if/else statement. Regards, Nived N Happy Automation How to follow the signal when reading the schematic? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. To learn more, see our tips on writing great answers. It is a convenient way to write code that would otherwise have to be written in more cumbersome form as an anonymous method or a generic delegate or an expression tree. "No deals" : (Deals.Count() == 1 ? if (condition) { query = query.Where (b => b == "something else"); } You can use the WhereIf statement method avaialbe in LINQ in this way: query = query.WhereIf (condition, b => b == "something else"); So your final code will be: When to use multiple where clauses in LINQ? dateTo, List<AccountRootType> accountRootTypes = null . Why is this the case? Styling contours by colour and by line thickness in QGIS, Time arrow with "current position" evolving with overlay number, Partner is not responding when their writing is needed in European project application, ERROR: CREATE MATERIALIZED VIEW WITH DATA cannot be executed from a function, Recovering from a blunder I made while emailing a professor. And because a query variable does not store the results of the query, you can modify it or use it as the basis for a new query at any time, even after it has been executed. When to use .First and when to use .FirstOrDefault with LINQ? I need the record with id equals to that conditionVariable. Making statements based on opinion; back them up with references or personal experience. b : c) - however, I don't know if it will work with your different queries like that (after all, how would your write the TSQL?). For example, assigning grades (A, B, C) based on marks obtained by a student. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Why should transaction_version change with removals? If so then how can I do that? You need to understand that what's in the WEHRE clause is a boolean expression not a statement. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? data source) contains a specified element or not. To learn more, see our tips on writing great answers. What is the correct way to screw wall and ceiling drywalls? ADO.NET, Entity Framework, LINQ to SQL, Nhibernate. This should work. For this example I have used of Northwind database that you can download using the link given below. Means it is mostly used in querying purpose like fetch largest value from an array. This is same as a new list created. Edit: You can make combinations like this: In this case your are using deals.Count() a lot, so you can store the result in a temporary variable using the LINQ let syntax: Thanks for contributing an answer to Stack Overflow! If a question is poorly phrased then either ask for clarification, ignore it, or. Don't tell someone to read the manual. The variable is limited to the block it is declared in. The primary formula to use it is: var SubListName = from ValueHolder in List group ValueHolder by Category; The new keywords are group and by. Connect and share knowledge within a single location that is structured and easy to search. Not the answer you're looking for? Has 90% of ice around Antarctica disappeared in less than a decade? I need this because I will need sorting based on Status. Chakra Basics; Gemstones; Main Menu The LINQ Contains Method in C# is used to check whether a sequence or collection (i.e. To get started using LINQ, all that you really have to know about extension methods is how to bring them into scope in your application by using the correct using directives. In the below example, we are using the LINQ Method Syntax to . You can perform the where separately from the main query: You need to declare the result variable before the first if-else. Acidity of alcohols and basicity of amines. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. @NithinPaul - probably best if you post a new question, explaining exactly what you're trying to do. @value= TotalBookingPrice Make use of WhereIf extenstion method avaialbe in linq Example if (SearchControlMain.PostingID.HasValue) query = query.Where (q => q.PostingID == SearchControlMain.PostingID); instead of above go for the below query = query.WhereIf (SearchControlMain.CategoryID.HasValue, q => q.CategoryID == SearchControlMain.CategoryID); This article shows the three ways in which you can write a LINQ query in C#: Use query syntax. LINQ In sql I use like this: Classcud2 ob1 = new Classcud2 ( "select * from tbl_usertotalrating where store_name='" + TxtCompany.Text + "'" ); if (ob1.ds.Tables [0].Rows.Count > 0 ) { // what i want } else { // what i want } but my problem is I want to use "if" "else" condition in linq, In linq : From Frequently Asked Questions (LINQ to SQL) Q. if (value >= 22) You're welcome to try, of course Answer above is not suitable for complicate Linq expression. The region and polygon don't match. The following example shows how the three parts of a query operation are expressed in source code. I would put the p.ConditionVariable test at the beginning so taht it is the first thing checked (as && operations stop at the first failing condition.
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