Web Server ProgrammingC#

ContentA Summary on the C# Language

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Introduction to C#

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Variable Declarations in C#int x;int x = 5;string s;string s1, s2;object o;object obj = new object();public string name;

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StatementsResponse.Redirect("NewPage.aspx");x = y + 5;a = b = c = 5;

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Comments// This is a comment/* Thisisamultilinecomment*/

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Arraysstring[] course = new string[3];course[0] = "Web";course[1] = "Server";course[2] = "Programming";

int[] arr = new int[5]{1, 2, 3, 4, 5};int[][] mat = new int[2][3];mat[1][2] = 5;

int [,] mat = new int[3,4];mat[2,3] = 5;

char[] delimeters = new char[]{' ', '\r', '\n'};

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Indexed Properties// Creating arrays:int[] arr = new int[100];int[,] mat = new int[50, 100];

// Accessing array elements:int x = arr[2];arr[0] = 5;string name = Request.QueryString["name"];

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Propertiesprivate string m_Username;

public string Username { get { return m_Username; } set { m_Username = value; }}

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Propertiespublic string Name { get { return TextBox1.Text; } set { if (value.StartsWith("m")) { TextBox1.Text = value; } }}

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Automatic Propertiespublic string Username {get; set;}

A private variable to hold the value of the property is automatically created by the compiler

It can be used after C# 3.0You can create this type of properties in

Visual Studio by typing prop and pressing TAB key two times

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Why Properties?Allows read-only and write-only fieldsCan validate a field when it is assignedInterface and implementation of data my

differ (i.e., value can be written into a Label control)

Visual Studio IDE can list properties of an object when dot-key is pressed (intellisense)

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Enumerations// Declare the enumeration:public enum MessageSize { Small = 0, Medium = 1, Large = 2}

// Create a field or property:MessageSize msgSize;

// Assign a value:msgSize = MessageSize.Medium;

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Declaring and Calling Methodsprivate int Add(int a, int b) { return a + b;}

public void PrintHeader() { Console.WriteLine("This is a header");}

int z = Add(x, y);PrintHeader();

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If Statementif (a == 3) TextBox1.Text = "three";

if (a == 3){ TextBox1.Text = "three"; Label1.Text = "four";}

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If, Else, Else Ifif (a == 1) Label1.Text = "one";else if (a == 2) Label1.Text = "two";else Label1.Text = "other";

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Case Statementint num = 5;switch (num) { case 1: Label1.Text = "one"; break; case 2: case 3: Label1.Text = "two or three"; break; default: Label1.Text = "other"; break;}

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Case Statementstring color = "blue";switch (color) { case "red": Label1.Text = "Red"; break; case "blue": Label1.Text = "Blue"; break; default: Label1.Text = "Not Red Nor Blue"; break;}

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Case Statementenum MessageSize {Small, Medium, Large};MessageSize msgSize = MessageSize.Small;switch (msgSize) { case MessageSize.Small: Label1.Text = "S";

break; case MessageSize.Medium: Label1.Text = "M";

break; case MessageSize.Large: Label1.Text = "L";

break; default: Label1.Text = "---";

break;}

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For Loopfor (int i = 0; i < 10; i++) single_statement();

for (int i = 0; j < 10; k %= 2) { statement1(); statement2();}

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Foreach Loopint[] arr = new int[]{5, 7, 9, 10, 3};

foreach (int number in arr){ Label1.Text += number.ToString() + "<br/>";}

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While Loopint n = 5;while (n > 0){ Label1.Text += n.ToString() + "\r\n"; n--;}

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Do..While Loopint grade = 0;do{ grade += DoNextHomework();} while (grade < 100);

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Exception Handlingtry { // Code that throws exception} catch (OverflowException e) { // Catch a specific exception} catch (Exception e) { // Catch the generic exceptions} finally { // Execute some cleanup code}

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String Operationsstring s1 = "Web";string s2 = "Programming";string s3 = s1 + " " + s2;s3 += " (Server Side)";

// Use StringBuilder class for performance:StringBuilder s3 = new StringBuilder();s3.Append("Web");s3.Append(" Programming");

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Type Casting and Conversiondouble d = 5.4321;

int n = (int)d;

string s = n.ToString();

int n = int.Parse("54321");

double d = double.Parse("54.321");

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