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Cannot Be Converted To System.predicate

Borders table Latex more hot questions question feed lang-cs about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life / Arts The first version is a different type of lambda: the expression lambda. Expressions Expressions are a fundamental addition to C# that allows LINQ to work its magic. private bool ContainsAndrew(string val) { return val == "Andrew"; } //now to your list you would say: List BodyWords = new List(); BodyWords.Add("Peter"); BodyWords.Add("Paul"); bool containsAndrew = BodyWords.Exists(ContainsAndrew); The list will http://electrictricycle.net/cannot-be/cannot-be-converted-to-system.html

Wait... Why put a warning sticker over the warning on this product? Similar topics best method to convert list of string to vector? It's quick & easy. More about the author

more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed Pingback: [RESOLVED]What is difference between delegate & predicate | ASP Questions & Answers() Ads About Me I'm the chief architect at Headspring in Austin, TX. Is it possible to write division equation in more rows?

Not the answer you're looking for? For instance, here's a Predicate which tests for a string having a length 5 or more: Predicate lengthTester = delegate(string x) { return x.Length >= 5; }; (That's using an anonymous private List BodyWords = new List(); string word = "Andrew"; the following causes a compilation error: if (!BodyWords.Exists(word)) { } Thanks, Dec 20 '05 #1 Post Reply Share this Question 5 The difference is easy to spot, here are two identically functioning lambdas: public void LambdaExpressionsAndStatements() { var books = GetBooks(); var exprBooks = books.Find(book => book.Author.Contains("Fowler")); var stmtBooks = books.Find(book =>

Not the answer you're looking for? Word for "using technology inappropriately"? But LINQ query expressions (the SQL-like from..where..select) requires expressions, not statements. What can figure out if the Find method of a generic list cannot take a generic method as a predicate or if I'm doing something wrong.

I created AutoMapper and am a co-author of the ASP.NET MVC in Action books. How can I prove its value? Wednesday, December 12, 2012 3:38 PM Reply | Quote Microsoft is conducting an online survey to understand your opinion of the Msdn Web site. Login Create account Language Chinese Spanish Japanese Korean Portuguese Ask a question Spaces Default Help Room META Moderators Topics Questions Users Badges Home / 0 Question by LocoAbreu94 · Mar 28,

The Find method's signature is: public T Find(Predicate match) Predicate is a delegate type, so how does the "book.Author.Contains" part of the first lambda get converted to a delegate? http://answers.unity3d.com/questions/648503/listfindindex-error-c-1.html Any easy answer what is wrong here? We are making improvements to UA, see the list of changes. Hope that helps Mark Dawson http://www.markdawson.org "Andrew Robinson" wrote: Any easy answer what is wrong here?

delegate bool Predicate(T obj) So if you want to search your list to see if it contains a value of "Andrew" you will need to create a method that matches the http://electrictricycle.net/cannot-be/cannot-be-converted-to-system-web-ui-control.html About Jimmy Bogard I'm a technical architect with Headspring in Austin, TX. true : false;

} } ‹ Previous Thread|Next Thread › This site is managed for Microsoft by Neudesic, LLC. | © 2016 Microsoft. Dec 20 '05 #5 P: n/a Jon Skeet [C# MVP] Andrew Robinson wrote: Alright, looks like I should be using 'Contains' instead of 'Exists' but I would still like to

How can tilting a N64 cartridge cause such subtle glitches? Add comments to a Python script and make it a bilingual Python/C++ “program” In a company crossing multiple timezones, is it rude to send a co-worker a work email in the Dawson Hi Andrew, your problem is that the Exists method expects a Predicate which is another way of saying you need to put a delegate that returns a bool and accepts Check This Out A Predicate is something which returns true or false when given an item of the appropriate type.

Does sputtering butter mean that water is present? To help users navigate the site we have posted a user guide. Join them; it only takes a minute: Sign up How to find an index of a string within a List in .Net 2.0 up vote 2 down vote favorite I am

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Most folks won't develop any APIs that use Expression (the actual type behind the expression trees). true : false; } } //Project Class public class Project : ISearchByName { private string name; public string Name { get{ return this.name;} set{this.name= value;} } } Reply StrongTypes Edward's Professional Education Center Pragmatic Bookshelf ReSharper - Develop with Pleasure! These brackets are a statement block, and can contain any old C# code.

Stephen J Whiteley Marked as answer by Martin Xie - MSFT Friday, December 12, 2008 2:35 PM Friday, December 05, 2008 6:11 PM Reply | Quote Moderator All replies 1 Sign So we couldn't do something like this: var exprBooks = books.Find(book => book.Author.Split(' ')); We get the compiler error: Cannot convert lambda expression to delegate type 'System.Predicate' because some of the Bookmark the permalink. this contact form The second lambda has brackets.

Friday, December 05, 2008 5:15 PM Reply | Quote Answers 1 Sign in to vote Nate A Miller said:Whenever I try to find a certain value in a list:Dim strName as string = txtName.textlistFiles.Find(strName)I Privacy Statement| Terms of Use| Contact Us| Advertise With Us| CMS by Umbraco| Hosted on Microsoft Azure Feedback on ASP.NET| File Bugs| Support Lifecycle All rights reserved. Unless you're someone like Oren or Jeremy of course.

Anyone know what it is? A LINQ query expression is compiled into an expression tree, mixed in with the extension method calls to the LINQ query extensions (Where, Select, Union etc.) Here's another way to write How did early mathematicians make it without Set theory? It's why you can't do this in a LINQ query expression: var linqBooks = from book in books where { return books.Author.Contains("Fowler"); } select book; I get a nasty compile error: