Csharp Articles - Page 132 of 258

There are various categories of characters, operators, and constructs that lets you to define regular expressions. One of them is Grouping Constructs. Grouping constructs describe sub-expressions of a regular expression and capture substrings of an input string. The following table lists the grouping constructs. Grouping construct Description Pattern Matches ( subexpression ) Captures the matched subexpression and assigns it a zero-based ordinal number. (\w)\1 "ee" in "deep" (?< name >subexpression) Captures the matched subexpression into a named group. (?< double>\w)\k< double> "ee" in "deep" (?< name1 -name2 >subexpression) Defines a balancing group ... Read More

Gets or sets the value associated with the specified key. You can also use the Item property to add new elements.If a key does not exist, then you can include it like −myCollection["myNonexistentKey"] = myValueThe following is the code showing how to work with Item property of Hashtable class in C#.Example Live Demousing System; using System.Collections; namespace Demo {    class Program {       static void Main(string[] args) {          Hashtable ht = new Hashtable();          ht.Add("One", "Amit");          ht.Add("Two", "Aman");          ht.Add("Three", "Raman");       ... Read More

Var is strictly typed in C#, whereas dynamic is not strictly typed. Var declaration var a = 10; Dynamic declaration dynamic a = 10; A Var is an implicitly typed variable, but it will not bypass the compile time errors. Example of var in C# var a = 10; a = "Demo"; // gives compile error Example of dynamics in C# dynamic a = 10; a = "Demo"; // won’t give error

Quantifiers in C# specify how many instances of the previous element (which can be a character, a group, or a character class) must be present in the input string for a match to occur. Quantifier Description Pattern Matches * Matches the previous element zero or more times. \d*\.\d ".0", "19.9", "219.9" + Matches the previous element one or more times. "be+" "bee" in "been", "be" in "bent" ? Matches the previous element zero or one time. "rai?n" "ran", "rain" { n } Matches the previous element exactly n ... Read More

To debug your code, you need methods or properties, which are provided by Debug Class in C#. The debugger class is used to set communication with the debugger. Debug Class The Debug class inherits from System.Diagnostics. The syntax is − public static class Debug The following are the properties of the debugger class. Sr.No Property & Description 1 AutoFlush Gets or sets a value stating whether Flush should be called on the Listeners or not. 2 IndentLevel The indent level is set 3 IndetntSize The number of spaces in the ... Read More

Firstly, set a link list and add some elements.Demo list = new Demo(); list.Push(50); list.Push(100); list.Push(150);Now to delete nth element from headnode, pass what you want to delete. If you will set 1, then it will delete the head node.Exampleif (val == 1) {    head = head.Next;    return; } // n points to the node before the node we wish to delete Node n = head; // m is the node set to be deleted Node m = head.Next; for (int i = 2; i < val; i++) {    n = n.Next;    m = m.Next; } ... Read More

Dictionary is a collection of keys and values in C#. Dictionary is included in the System.Collection.Generics namespace.The following are the methods −Sr.NoMethod & Description1AddAdd key-value pairs in Dictionary2Clear()Remove all keys and values3RemoveRemoves the element with the specified key.4ContainsKeyChecks whether the specified key exists in Dictionary.5ContainsValueChecks whether the specified key value exists in Dictionary.6CountCount the number of key-value pairs.7ClearRemoves all the elements from Dictionary.Let us see how to add elements into a Dictionary and display the count.Example Live Demousing System; using System.Collections.Generic; public class Demo {    public static void Main() {       IDictionary d = new Dictionary();     ... Read More

Exception Propogation can be understood by how exception handling works in C#.In try, when an exception occurs the corresponding catch blocks are checked. This is done to see if they can catch the exception. If no matching exception is found, the exception is propagated to a higher-level try block. This repeats until the exception is caught. In case, the exception isn’t caught, the execution of the program comes to an end.The above concept is explain in the below example showing nested try statements.Example Live Demousing System; using System.Text; public class Demo {    public static void Main() {       ... Read More

Get the keys in the SortedList using the keys property of SortedList class in C#. We have first set the SortedList property with elements.SortedList sl = new SortedList(); sl.Add("ST0", "One"); sl.Add("ST1", "Two"); sl.Add("ST2", "Three"); sl.Add("ST3", "Four"); sl.Add("ST4", "Five"); sl.Add("ST5", "Six"); sl.Add("ST6", "Seven");Now use the keys property to get the keys.ICollection key = sl.Keys;The following is the complete code to implement keys property of SortedList class.Example Live Demousing System; using System.Collections; namespace Demo {    class Program {       static void Main(string[] args) {          SortedList sl = new SortedList();          sl.Add("ST0", "One");   ... Read More

In Dynamic binding, the compiler will not do type checking at compile time. At run time, the checking is done.Use it to avoid the restriction of anonymous types to one method. This is only because the type name is visible only to the compiler; therefore, you cannot declare it as the return value of a method.Examplepublic dynamic GetAnonymousType() {    return new {       StudentName = "Tom",       Subject = "Java",    }; }Above, the method is set to be dynamic, that would means the compiler won’t do type checking at compile time.public dynamic GetAnonymousType() { }