Here's how you can make those apps faster. Creating a comma separated list from IList or IEnumerable, Get property value from string using reflection. Query expressions make frequent use of anonymous types, which can only be initialized by using an object initializer, as shown in the following declaration. Generally, the IEnumerable interface will represent an object that can be enumerated and it's a base interface for all non-generic collections that can enumerate. Correlates the elements of two sequences based on key equality and groups the results. Returns the number of elements in a sequence. Why is it shorter than a normal address? The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value. [duplicate]. Using LINQ you can get all customers names (values) having specific value in this way: var valuesList = items.Where(x => x.Something == myVar).Select(v => v.Name).ToList(); For single customer name you can do this: Now, get the IEnumerable equivalent. Creates a Dictionary from an IEnumerable according to a specified key selector function and key comparer. When you implement IEnumerable, you must also implement IEnumerator or, for C# only, you can use the yield keyword. . Computes the sum of the sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence. Projects each element of a sequence to an IEnumerable and flattens the resulting sequences into one sequence. Required fields are marked *. Splitting string by spaces but ignore spaces inside a quote. Then Ienumerable interface has a method called GetEnumerator which returns an object of IEnumerator. c# - How to get IEnumerable list values? - Stack Overflow Appends a value to the end of the sequence. For the non-generic version of this interface, see System.Collections.IEnumerable. I tried this: foreach (var v in list) // also list[i] { cnt= v.Count; strt= v.Start; nd = v.End; }. For example, if index = 3, it should provide me 3rd item of the To learn more, see our tips on writing great answers. The . Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. How do I stop the Flickering on Mode 13h? Returns distinct elements from a sequence according to a specified key selector function. Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents by using the specified key comparer. Get a list of Enum members. Very clear and sustinct. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. The following example shows two simple collection initializers: The following collection initializer uses object initializers to initialize objects of the Cat class defined in a previous example. Projects each element of a sequence to an IEnumerable, and flattens the resulting sequences into one sequence. Produces the set intersection of two sequences by using the specified IEqualityComparer to compare values. Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements. Anyone who uses the method should be able to treat it as though it synchronously returns an array. c# - Reflection, how to get the PropertyType value and convert to You can use a foreach statement to loop through it, you can use LINQ to map or reduce it in a hundred different ways, or you can explicitly cast it to an array with .ToArray() and access elements by index. But how do i get the name/s from the results view ?of the variable 'p' ? Well, thats a bunch of code the computer didnt have to execute. Think of IEnumerable<T> as a factory for creating IEnumerator<T>. Some classes may have collection properties where the property is read-only, like the Cats property of CatOwner in the following case: You will not be able to use collection initializer syntax discussed so far since the property cannot be assigned a new list: However, new entries can be added to Cats nonetheless using the initialization syntax by omitting the list creation (new List), as shown next: The set of entries to be added simply appear surrounded by braces. Returns the minimum value in a generic sequence according to a specified key selector function. Ive not verified, but I suspect any Linq method which returns IEnumerable will be lazily evaluated, whereas all others will necessarily evaluate the collection to return a fully initialized object, i.e. Notice that instead of indexer syntax, with parentheses and an assignment, it uses an object with multiple values: This initializer example calls Add(TKey, TValue) to add the three items into the dictionary. Generic: The return value is a generic IEnumerable collection of ints. How to convert a sequence of integers into a monomial. This may seem counterintuitive, but in a lot of cases its a good thing. Returns a filtered collection of the child elements of every element and document in the source collection. Return The return value is a generic IEnumerable collection of ints. So in your example there is actually an Customer[] which implements that interface, hence it will use the indexer. Both variants work with the Dictionary class. Enumerates and transforms a sequence, and produces an immutable dictionary of its contents. These two different ways to initialize associative collections have slightly different behavior because of the method calls the compiler generates. Object and Collection Initializers - C# Programming Guide Constructs an immutable dictionary based on some transformation of a sequence. What was the purpose of laying hands on the seven in Acts 6:6. }. In other words, if something is an IEnumerable, you can mostly think of it like an array or a list. Invokes a transform function on each element of a sequence and returns the minimum Int64 value. This cleared up a lot of confusion I had regarding yield return. 2) in the final code block, // LINQ methods are lazily evaluated as well half true. Only elements that have a matching XName are included in the collection. With LINQ you can visit this list and map them to a new class where you can access from anywhere. Invokes a transform function on each element of a sequence and returns the minimum Int32 value. On whose turn does the fright from a terror dive end? in a customized tabular view.. The preceding sample generates code that calls the Item[TKey] to set the values. [Solved] How to get value from IEnumerable collection | 9to5Answer If your IEnumerable is not a materialized collection, but a generated sequence, calling ElementAt method multiple times will cause the sequence to be generated multiple times. For example if i want to make something like: string test = p.(something here that will give me the first index of the Results View) but i didn't find the property that hold the Results View. Computes the sum of the sequence of Double values that are obtained by invoking a transform function on each element of the input sequence. Returns a filtered collection of elements that contains the ancestors of every node in the source collection. Some tools (like ReSharper) will warn you against multiple enumeration for this reason. Dynamic languages allow for a lot of flexibility in typing sometimes too much. Is it possible to control it remotely? Its important to point out that many iterators are not as simple as the ones weve been using here. Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer. What was the actual cockpit layout and crew of the Mi-24A? IEnumerable. Correlates the elements of two sequences based on equality of keys and groups the results. When a yield method returns an IEnumerable type object, this object implements both IEnumerable and IEnumerator. It keeps these sample values: I want to access and assign to any variables these Count, Start and End values, whenever I want. Computes the average of a sequence of Single values that are obtained by invoking a transform function on each element of the input sequence. Expanding the Results View Will Enumerate the IEnumerable Using DB Context Word order in a sentence with two clauses, enjoy another stunning sunset 'over' a glass of assyrtiko. Every time we iterate over numbers, it will start over at the beginning of the iterator method and yield all the same values over again. That can be expensive. Applies a specified function to the corresponding elements of two sequences, producing a sequence of the results. The keys are compared by using a specified comparer. IEnumerable contains a single method that you must implement when implementing this interface; GetEnumerator, which returns an IEnumerator object. Creates a Lookup from an IEnumerable according to a specified key selector function and key comparer. Returns the only element of a sequence that satisfies a specified condition or a default value if no such element exists; this method throws an exception if more than one element satisfies the condition. Sorts the elements of a sequence in ascending order according to a key. More info about Internet Explorer and Microsoft Edge, Use object initializers (style rule IDE0017), Use collection initializers (style rule IDE0028). The output of running Main() in the above snippet is false. Tikz: Numbering vertices of regular a-sided Polygon, Word order in a sentence with two clauses. Returns the maximum value in a generic sequence according to a specified key selector function and key comparer. Returns the maximum value in a generic sequence. Projects each element of a sequence to an IEnumerable, flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein. You can specify indexed elements if the collection supports read / write indexing. For a simple iterator like the one Ive written, thats technically okay to do. Sorts the elements of a sequence in descending order by using a specified comparer. Returns the only element of a sequence, and throws an exception if there is not exactly one element in the sequence. I have IEnumerable list of customerList and index. Learn how your comment data is processed. IEnumerable C# | Top 5 Examples to Implement of IEnumerable C# - EduCBA What's the cheapest way to buy out a sibling's share of our parents house if I have no cash and want to pay less than the appraised value? We can abstract the loop itself out. Now, I have a problem that I have to assign these data into several TextBoxes. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Asking for help, clarification, or responding to other answers. Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type. Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents. Looking for job perks? Luckily, ElementAt checks to see whether the argument is an IList and uses index-based access if possible. public string GetCustomerName(IEnumerable<Customer> customers, int id) { return customers.First(c => c.Id == id).Name; } Solution 3. Constructs an immutable dictionary from an existing collection of elements, applying a transformation function to the source keys. Func, Func, Func, Projects each element of a sequence into a new form by incorporating the element's index. How to Enumerate an Enum in C# - Code Maze To subscribe to this RSS feed, copy and paste this URL into your RSS reader. GetEnumerator returns an IEnumerator that can only MoveNext and Reset. 1. What is Wario dropping at the end of Super Mario Land 2 and why? This should take as 1st parameter the item from the collection detected. Customer c = customerList.ElementAt(currentIndex); // 4th Use ElementAtOrDefault to prevent an exception if there are not enough items, then you get null: Customer c = customerList.ElementAtOrDefault(currentIndex); // 4th or null These methods are optimized in a way that they use the IList<T> indexer. Returns the first element in a sequence that satisfies a specified condition. In contrast, ToArray() is a method (not a cast) which enumerates and potentially copies ( la List.ToArray() ) the collection in question, with all the side-effects mentioned in the remainder of the article. Object initializers can set indexers, in addition to assigning fields and properties. Determines whether any element of a sequence satisfies a condition. The following example shows how to use an object initializer with a named type, Cat and how to invoke the parameterless constructor. Step 2: Execute it further and see the result variable, it prompts you with "expanding the results view will enumerate the ienumerable". Enumerates and transforms a sequence, and produces an immutable sorted dictionary of its contents by using the specified key and value comparers. Returns a new enumerable collection that contains the last count elements from source. The specified seed value is used as the initial accumulator value. How can I do this? When this query is executed, the productInfos variable will contain a sequence of objects that can be accessed in a foreach statement as shown in this example: Each object in the new anonymous type has two public properties that receive the same names as the properties or fields in the original object. To prove it, run the following code in LINQPad. The default equality comparer is used to compare keys. Enumerates a sequence, produces an immutable hash set of its contents, and uses the specified equality comparer for the set type. 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Returns distinct elements from a sequence by using a specified IEqualityComparer to compare values. Sorts the elements of a sequence in ascending order. For example, to read the values on the first element: var firstCount = list.First().Count; var firstStart = list.First().Start; var firstEnd = list.First().End; The index of each source element is used in the projected form of that element. Filters a sequence of values based on a predicate. Returns the only element of a sequence that satisfies a specified condition, or a specified default value if no such element exists; this method throws an exception if more than one element satisfies the condition. Step 3: You can make it enumerable after converting to a list type with the help of the .ToList () method. To get a list, call ToList () after casting. Returns a DataTable that contains copies of the DataRow objects, given an input IEnumerable object where the generic parameter T is DataRow. For example. The object initializer syntax enables you to specify arguments for a constructor or omit the arguments (and parentheses syntax). In C#, you can add items to an IEnumerable collection by converting it to an ICollection or an IList that supports adding items, or by using the yield keyword to create a new sequence that includes the original items and the new items.. Here's an example code that demonstrates how to add items to an IEnumerable collection:. How do I get a consistent byte representation of strings in C# without manually specifying an encoding? To remain compatible with methods that iterate non-generic collections, IEnumerable implements IEnumerable. 565), Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. arr.AsEnumerable(); .