The problem is that you are trying to use procedural control flow logic in the where clause. It contains well written, well thought and well explained computer science and programming articles, quizzes and practice/competitive programming/company interview Questions. If you are using LinQ with EF Core, an easy example can be this- var orderedData = await _dbContext.ModelName .OrderBy (c => c.Name.Length.Length > 4 ? C# if Statement The if statement contains a boolean condition followed by a single or multi-line code block to be executed. The complete example code is given below. This
You need to declare result before the if statement: Or you can keep the var declaration in this other variant: Now you should somehow find a way to either change that if or remove it completely because result cannot be null at that point. You need to define the variable out of blocks, but then you need to be specific about the type, because C# compiler needs direct assignment expression to infer the type for var keyword. The body of the lambda is just the same as the expression in query syntax or in any other C# expression or statement; it can include method calls and other complex logic. What sort of strategies would a medieval military use against a fantasy giant? s.StudentID == StudentUserID : (s.TutorUserID == TutorUserID && s.StudentID == StudentUserID)), where s.TutorUserID == TutorUserID && s.StudentID == StudentUserID. Where produces a filtered sequence, and then Orderby operates on that sequence by sorting it. 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 : Why are non-Western countries siding with China in the UN? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. I need to ignorefilter condition if line id is 0 and empty. @Richard in case if i need to call a function on else condition, is it possible? To learn more, see our tips on writing great answers. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. "One deal" : "Many deals")), How Intuit democratizes AI development across teams through reusability. We can see there is just one income between 25000 and 40000. What's the difference between a power rail and a signal line? For more information, see Lambda Expressions. The following code snippet shows how to write the query to fetch data from three data sources using the LINQ Method syntax. Wrong answer. email is in use. Asking for help, clarification, or responding to other answers. 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?). Are there tables of wastage rates for different fruit and veg? Something like from p in db.products if p.price>0 select new { Owner=from q in db.Users select q.Name } else select new { Owner = from r in db.ExternalUsers select r.Name } 0. foreach - Declare variable of different type foreach Type - Declare a variable using a Type variable Console.ReadLine else-if - Console.ReadLine unexpected behaviour in else-if statement If, Else-If - If, Else-If Logic Check if . Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, ifthen to concat SQL queries, equivalent in LINQ - VB NET, C# Linq Query on database using field name as a variable, Building a lambda WHERE expression to pass into a method, Dynamic LINQ OrderBy on IEnumerable / IQueryable. if p.conditionVariable == 0 the following remains the same. Acidity of alcohols and basicity of amines. where ID= 94685, OTDataContext dc = new OTDataContext();
The site does not provide any warranties for the posted content. Thanks! Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? Regards, Nived N Happy Automation Should isn't does. "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. I think you want to make a || between conditions and table2 will be queried based on p.CondtionVariable. @HafizH can you give a feedback of solutions below? The output from the two examples is identical. I have a scenario where table2 has a column called ConditionVariable and id. 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. The Select clause is used to shape the data. The following example the data can be data bound or unbound. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. You also must use a method call for a query that retrieves the element that has the maximum value in a source sequence. ); } else { roles = roles.Where (dp => . Hope you got my point, I have no idea what you are asking either but it sounds like the answer involves a. @Tudor, I can't understand the performance problem. The "return value" is just the expression result. What video game is Charlie playing in Poker Face S01E07? Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, LINQ equivalent of foreach for IEnumerable, Concat all strings inside a List using LINQ, Using LINQ to remove elements from a List. I have no idea what you are asking, please clarify the question. The ValueHolder factor is the same variable created from the from operator. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy.
LINQ: When to use SingleOrDefault vs. FirstOrDefault() with filtering criteria, How to handle a hobby that makes income in US, Short story taking place on a toroidal planet or moon involving flying, Bulk update symbol size units from mm to map units in rule-based symbology. For a trivial example of the type of thing you can do: You can do much richer things, but I really doubt you can pick the table in the conditional. Provide an answer or move on to the next question. More info about Internet Explorer and Microsoft Edge. This article shows the three ways in which you can write a LINQ query in C#: Use query syntax. rev2023.3.3.43278. About an argument in Famine, Affluence and Morality. Status = (Deals.Count() == 0 ? code - block - 1 : code - block - 2. LINQ queries can be applied for CRUD operations . rev2023.3.3.43278. Using a conditional if statement in a Linq query; Case Statement In linq query on where condition using c#; LINQ statement using Orderby and Distinct in sub query; How to avoid Query Plan re-compilation when using IEnumerable.Contains in Entity Framework LINQ queries? These extension methods are meant to conditionally apply LINQ clauses if a boolean is set to true. How to follow the signal when reading the schematic? If we compare the inline if statement with the if . How can I explain to my manager that a project he wishes to undertake cannot be performed by the team? LINQ (Language Integrated Query) is a Microsoft programming model and methodology that essentially adds formal query capabilities into Microsoft .NET-based programming languages. I assume from db that this is LINQ-to-SQL / Entity Framework / similar (not LINQ-to-Objects); Generally, you do better with the conditional syntax ( a ? Is that what you want? What is the purpose of this D-shaped ring at the base of the tongue on my hiking boots? In my case there were two "conditional" where depending on search keys, so I did: This is how can you can do it with the noob Linq syntax. When to use .First and when to use .FirstOrDefault with LINQ? The primary formula to use it is: var SubListName = from ValueHolder in List group ValueHolder by Category; The new keywords are group and by. @ile - Absolutely, you just need to use some parenthesis.. Why do small African island nations perform better than African continental nations, considering democracy and human development? UiPath | LINQ IF Condition | IF for Arrays | IF for Data Tables | IF for empty output of LINQ query 1,442 views Nov 11, 2021 #rpa #uipath #linq .more Dislike Share. SingleOrDefault () method will return the only element in the sequence that . Thanks for contributing an answer to Stack Overflow! In the previous example, notice that the conditional expression (num % 2 == 0) is passed as an in-line argument to the Where method: Where(num => num % 2 == 0). To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 1 solution Solution 1 You don't need LINQ or a ternary operator. However, the query syntax must be translated into method calls for the .NET common language runtime (CLR) when the code is compiled. Is it possible to create a concave light? Powershell Or Python3 - CSV file: remove row based on duplicates in a column, with IF ELSE based conditions in another column; else statement issue powershell script; This is only viable if you don't need the element's value in the condition. For this example I have used of Northwind database that you can download using the link given below. Query syntax and method syntax are semantically identical, but many people find query syntax simpler and easier to read. Why is this sentence from The Great Gatsby grammatical? Most queries in the introductory Language Integrated Query (LINQ) documentation are written by using the LINQ declarative query syntax. How to show that an expression of a finite type must be one of the finitely many possible values? Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2, LINQ equivalent of foreach for IEnumerable. This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL). By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Not sure how to fix this. LINQ simplifies the queries by offering a consistent model for working with data across various kinds of sources and formats. There are three forms of if.else statements in C++. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Do new devs get fired if they can't solve a certain bug? You can assign the IEnumerable to an object reference, but once it's there, you can't do much of value with it; you can't enumerate it or call any linq methods on it without casting it back to IEnumerable. The region and polygon don't match. In the above syntax, a condition is an expression. Very useful if it does. Is this "correct". Connect and share knowledge within a single location that is structured and easy to search. switch-case can only compare values that can be used in a switch statement, such as integers and characters, while if/else can use any Boolean expression. Why are non-Western countries siding with China in the UN? In the above example, we selected the each resulted string elements. Thanks for contributing an answer to Stack Overflow! Execute the query. Asking for help, clarification, or responding to other answers. I'm not sure what the question is, but a possible answer could be: It would be a complicated way of saying something simple, though. LINQ: When to use SingleOrDefault vs. FirstOrDefault() with filtering criteria. Do new devs get fired if they can't solve a certain bug? To support grouping, the LINQ provides the group.by operation. Subscribe to my channel too if you hadn't done it already for more updates. 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. Why should transaction_version change with removals? Using LINQ Method Syntax, it is a little difficult to write the join query when joining more than two data sources. Is your question about building the expression-tree without the arg-names or anything different I did not catch? If condition2 is true, you are essentially doing && true which has no effect on the where clause. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How Intuit democratizes AI development across teams through reusability. Check this example. Does Counterspell prevent from any further spells being cast on a given turn? For example, you must use a method call to express a query that retrieves the number of elements that match a specified condition. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. In code, the commented part is what I need to solve Is there a way to write such query in LINQ? I need the record with id equals to that conditionVariable. The standard query operators are implemented as a new kind of method called extension methods. Syntax. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Why are trials on "Law & Order" in the New York Supreme Court? Some queries must be expressed as method calls. Has 90% of ice around Antarctica disappeared in less than a decade? The content must be between 30 and 50000 characters. All LINQ query operations consist of three distinct actions: Obtain the data source. However, I suggest rethinking your code and doing somthing like following: Please also note that result will never be null, therefore, I have replaced it with Any but it is not a gist of the question, I believe. Asking for help, clarification, or responding to other answers. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. LINQ to SQL avoids such . You need to understand that what's in the WEHRE clause is a boolean expression not a statement. This is same as a new list created. Not the answer you're looking for? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Is it possible to create a concave light? What if I have more than two cases, is there possibility to do that? In a LINQ query, the from clause comes first in order to introduce the data source ( customers) and the range variable ( cust ). When to use .First and when to use .FirstOrDefault with LINQ? With your particular code, the answer is really simple: In general though, to apply very different queries, you could either use: Or you could maybe use the conditional operator to construct the right predicate: Move the isDup test into the Where expression itself. Ask for this RAVE RE 850 E-TEC Ice Ripper XT 1.25 M.S. ncdu: What's going on with this second size column? 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. They are required. How is Jesus " " (Luke 1:32 NAS28) different from a prophet (, Luke 1:76 NAS28)? The following examples demonstrate some simple LINQ queries by using each approach listed previously. These operators are also used for implementing paging. 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? Is it possible to use If Else conditional in a LINQ query? The first where clause checks for the income that is greater than 25,000 and the second where clause looks for the income that is less than 45,000. Join Operators These LINQ query operators are used to combine multiple sequence into one sequence just like joins in SQL queries. 20 Bay Street, 11th Floor Toronto, Ontario, Canada M5J 2N8
//queryAllCustomers is an IEnumerable<Customer> var queryAllCustomers = from cust in customers select cust; The range variable is like the iteration variable in a foreach loop except that no actual iteration . A Computer Science portal for geeks. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. int value = (from p in dc.Patients
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How to use if else statement in combobox in VB.NET. Asking for help, clarification, or responding to other answers. The first time result is an int, the second time I declare a string, and the third time result is undeclared. 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); If a question is poorly phrased then either ask for clarification, ignore it, or. So you have two results, one in if block and one in else block which are different and are not visible outside their blocks. Modified today. What sort of strategies would a medieval military use against a fantasy giant?
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