解析C#编程的通用结构和程序书写格式规范

// A skeleton of a C# program using System;namespace YourNamespace{  class YourClass  {  }  struct YourStruct  {  }  interface IYourInterface   {  }  delegate int YourDelegate();  enum YourEnum   {  }  namespace YourNestedNamespace  {    struct YourStruct     {    }  }  class YourMainClass  {    static void Main(string[] args)     {      //Your program starts here...    }  }}

var currentPerformanceCounterCategory = new System.Diagnostics.  PerformanceCounterCategory();

if ((val1 > val2) && (val1 > val3)){  // Take appropriate action.}

// The following declaration creates a query. It does not run// the query.

var phrase = "lalalalalalalalalalalalalalalalalalalalalalalalalalalalalala";var manyPhrases = new StringBuilder();for (var i = 0; i < 10000; i++){  manyPhrases.Append(phrase);}//Console.WriteLine("tra" + manyPhrases);

// When the type of a variable is clear from the context, use var // in the declaration.var var1 = "This is clearly a string.";var var2 = 27;var var3 = Convert.ToInt32(Console.ReadLine());

// When the type of a variable is not clear from the context, use an// explicit type.int var4 = ExampleClass.ResultSoFar();

// Naming the following variable inputInt is misleading. // It is a string.var inputInt = Console.ReadLine();Console.WriteLine(inputInt);

var syllable = "ha";var laugh = "";for (var i = 0; i < 10; i++){  laugh += syllable;  Console.WriteLine(laugh);}

foreach (var ch in laugh){  if (ch == 'h')    Console.Write("H");  else    Console.Write(ch);}Console.WriteLine();

// Preferred syntax. Note that you cannot use var here instead of string[].string[] vowels1 = { "a", "e", "i", "o", "u" };// If you use explicit instantiation, you can use var.var vowels2 = new string[] { "a", "e", "i", "o", "u" };// If you specify an array size, you must initialize the elements one at a time.var vowels3 = new string[5];vowels3[0] = "a";vowels3[1] = "e";// And so on.

 // First, in class Program, define the delegate type and a method that // has a matching signature.// Define the type.public delegate void Del(string message);// Define a method that has a matching signature.public static void DelMethod(string str){  Console.WriteLine("DelMethod argument: {0}", str);} // In the Main method, create an instance of Del.// Preferred: Create an instance of Del by using condensed syntax.Del exampleDel2 = DelMethod;// The following declaration uses the full syntax.Del exampleDel1 = new Del(DelMethod);

static string GetValueFromArray(string[] array, int index){  try  {    return array[index];  }  catch (System.IndexOutOfRangeException ex)  {    Console.WriteLine("Index is out of range: {0}", index);    throw;  }}

// This try-finally statement only calls Dispose in the finally block.Font font1 = new Font("Arial", 10.0f);try{  byte charset = font1.GdiCharSet;}finally{  if (font1 != null)  {    ((IDisposable)font1).Dispose();  }}// You can do the same thing with a using statement.using (Font font2 = new Font("Arial", 10.0f)){  byte charset = font2.GdiCharSet;}

Console.Write("Enter a dividend: ");var dividend = Convert.ToInt32(Console.ReadLine());Console.Write("Enter a divisor: ");var divisor = Convert.ToInt32(Console.ReadLine());// If the divisor is 0, the second clause in the following condition// causes a run-time error. The && operator short circuits when the// first expression is false. That is, it does not evaluate the// second expression. The & operator evaluates both, and causes // a run-time error when divisor is 0.if ((divisor != 0) && (dividend / divisor > 0)){  Console.WriteLine("Quotient: {0}", dividend / divisor);}else{  Console.WriteLine("Attempted division by 0 ends up here.");}

var instance1 = new ExampleClass();

ExampleClass instance2 = new ExampleClass();

// Object initializer.var instance3 = new ExampleClass { Name = "Desktop", ID = 37414,   Location = "Redmond", Age = 2.3 };// Default constructor and assignment statements.var instance4 = new ExampleClass();instance4.Name = "Desktop";instance4.ID = 37414;instance4.Location = "Redmond";instance4.Age = 2.3;

 public Form2(){  // You can use a lambda expression to define an event handler.  this.Click += (s, e) =>    {      MessageBox.Show(        ((MouseEventArgs)e).Location.ToString());    };} // Using a lambda expression shortens the following traditional definition.public Form1(){  this.Click += new EventHandler(Form1_Click);}void Form1_Click(object sender, EventArgs e){  MessageBox.Show(((MouseEventArgs)e).Location.ToString());}

var seattleCustomers = from cust in customers            where cust.City == "Seattle"            select cust.Name;

var localDistributors =  from customer in customers  join distributor in distributors on customer.City equals distributor.City  select new { Customer = customer, Distributor = distributor };

var localDistributors2 =  from cust in customers  join dist in distributors on cust.City equals dist.City  select new { CustomerName = cust.Name, DistributorID = dist.ID };

var seattleCustomers = from cust in customers            where cust.City == "Seattle"            select cust.Name;

var seattleCustomers2 = from cust in customers            where cust.City == "Seattle"            orderby cust.Name            select cust;

// Use a compound from to access the inner sequence within each element.var scoreQuery = from student in students         from score in student.Scores         where score > 90         select new { Last = student.LastName, score };