[转]c#.NET和VB.NET语法的比较
本文转自:http://www.cnblogs.com/lify0407/archive/2007/08/01/838589.html
VB.NET |
C# |
||||||||||
Comments | |||||||||||
' Single line only Rem Single line only |
// Single line /* Multiple line */ /// XML comments on single line /** XML comments on multiple lines */ |
||||||||||
Data Types | |||||||||||
Value Types Boolean Byte Char (example: "A"c) Short, Integer, Long Single, Double Decimal Date Reference Types Object String Dim x As Integer Console.WriteLine(x.GetType()) ' Prints System.Int32 Console.WriteLine(TypeName(x)) ' Prints Integer ' Type conversion Dim numDecimal As Single = 3.5 Dim numInt As Integer numInt = CType(numDecimal, Integer) ' set to 4 (Banker's rounding) numInt = CInt(numDecimal) ' same result as CType numInt = Int(numDecimal) ' set to 3 (Int function truncates the decimal) |
Value Types bool byte, sbyte char (example: 'A') short, ushort, int, uint, long, ulong float, double decimal DateTime (not a built-in C# type) Reference Types object string int x; Console.WriteLine(x.GetType()); // Prints System.Int32 Console.WriteLine(typeof(int)); // Prints System.Int32 // Type conversion double numDecimal = 3.5; int numInt = (int) numDecimal; // set to 3 (truncates decimal) |
||||||||||
Constants | |||||||||||
Const MAX_STUDENTS As Integer = 25 | const int MAX_STUDENTS = 25; | ||||||||||
Enumerations | |||||||||||
Enum Action Start [Stop] ' Stop is a reserved word Rewind Forward End Enum Enum Status Flunk = 50 Pass = 70 Excel = 90 End Enum Dim a As Action = Action.Stop If a <> Action.Start Then Console.WriteLine(a) ' Prints 1 Console.WriteLine(Status.Pass) ' Prints 70 Dim s As Type = GetType(Status) Console.WriteLine([Enum].GetName(s, Status.Pass)) ' Prints Pass |
enum Action {Start, Stop, Rewind, Forward}; enum Status {Flunk = 50, Pass = 70, Excel = 90}; Action a = Action.Stop; if (a != Action.Start) Console.WriteLine(a + " is " + (int) a); // Prints "Stop is 1" Console.WriteLine(Status.Pass); // Prints Pass |
||||||||||
Operators | |||||||||||
Comparison = < > <= >= <> Arithmetic + - * / Mod \ (integer division) ^ (raise to a power) Assignment = += -= *= /= \= ^= <<= >>= &= Bitwise And AndAlso Or OrElse Not << >> Logical And AndAlso Or OrElse Not Note: AndAlso and OrElse are for short-circuiting logical evaluations String Concatenation & |
Comparison == < > <= >= != Arithmetic + - * / % (mod) / (integer division if both operands are ints) Math.Pow(x, y) Assignment = += -= *= /= %= &= |= ^= <<= >>= ++ -- Bitwise & | ^ ~ << >> Logical && || ! Note: && and || perform short-circuit logical evaluations String Concatenation + |
||||||||||
Choices | |||||||||||
greeting = IIf(age < 20, "What's up?", "Hello") ' One line doesn't require "End If", no "Else" If language = "VB.NET" Then langType = "verbose" ' Use : to put two commands on same line If x <> 100 Then x *= 5 : y *= 2 ' or to break up any long single command use _ If whenYouHaveAReally < longLine And itNeedsToBeBrokenInto2 > Lines Then _ UseTheUnderscore(charToBreakItUp) 'If x > 5 Then x *= y ElseIf x = 5 Then x += y ElseIf x < 10 Then x -= y Else x /= y End If Select Case color ' Must be a primitive data type Case "pink", "red" r += 1 Case "blue" b += 1 Case "green" g += 1 Case Else other += 1 End Select |
greeting = age < 20 ? "What's up?" : "Hello"; if (x != 100) { // Multiple statements must be enclosed in {} x *= 5; y *= 2; } No need for _ or : since ; is used to terminate each statement. if (x > 5) x *= y; else if (x == 5) x += y; else if (x < 10) x -= y; else x /= y; switch (color) { // Must be integer or string case "pink": case "red": r++; break; // break is mandatory; no fall-through case "blue": b++; break; case "green": g++; break; default: other++; break; // break necessary on default } |
||||||||||
Loops | |||||||||||
' Array or collection looping Dim names As String() = {"Fred", "Sue", "Barney"} For Each s As String In names Console.WriteLine(s) Next |
Pre-test Loops:
// no "until" keyword while (i < 10) i++; Post-test Loop: // Array or collection looping |
||||||||||
Arrays | |||||||||||
Dim nums() As Integer = {1, 2, 3} For i As Integer = 0 To nums.Length - 1 Console.WriteLine(nums(i)) Next Dim twoD(rows-1, cols-1) As Single twoD(2, 0) = 4.5 |
int[] nums = {1, 2, 3}; for (int i = 0; i < nums.Length; i++) Console.WriteLine(nums[i]); float[,] twoD = new float[rows, cols]; twoD[2,0] = 4.5f; int[][] jagged = new int[3][] { new int[5], new int[2], new int[3] }; jagged[0][4] = 5; |
||||||||||
Functions | |||||||||||
' Pass by value (in, default), reference (in/out), and reference (out) Sub TestFunc(ByVal x As Integer, ByRef y As Integer, ByRef z As Integer) x += 1 y += 1 z = 5 End Sub Dim a = 1, b = 1, c As Integer ' c set to zero by default TestFunc(a, b, c) Console.WriteLine("{0} {1} {2}", a, b, c) ' 1 2 5 ' Accept variable number of arguments Function Sum(ByVal ParamArray nums As Integer()) As Integer Sum = 0 For Each i As Integer In nums Sum += i Next End Function ' Or use Return statement like C# ' Optional parameters must be listed last and must have a default value Sub SayHello(ByVal name As String, Optional ByVal prefix As String = "") Console.WriteLine("Greetings, " & prefix & " " & name) End Sub |
// Pass by value (in, default), reference (in/out), and reference (out) void TestFunc(int x, ref int y, out int z) { x++; y++; z = 5; }
int a = 1, b = 1, c; // c doesn't need initializing TestFunc(a, ref b, out c); Console.WriteLine("{0} {1} {2}", a, b, c); // 1 2 5 // Accept variable number of arguments int Sum(params int[] nums) { int sum = 0; foreach (int i in nums) sum += i; return sum; } int total = Sum(4, 3, 2, 1); // returns 10 /* C# doesn't support optional arguments/parameters. Just create two different versions of the same function. */ void SayHello(string name, string prefix) { Console.WriteLine("Greetings, " + prefix + " " + name); } |
||||||||||
Exception Handling | |||||||||||
' Deprecated unstructured error handling On Error GoTo MyErrorHandler ... MyErrorHandler: Console.WriteLine(Err.Description) Try y = 0 x = 10 / y Catch ex As Exception When y = 0 ' Argument and When is optional Console.WriteLine(ex.Message) Finally Beep() End Try |
Exception up = new Exception("Something is really wrong."); throw up; // ha ha try { y = 0; x = 10 / y; } catch (Exception ex) { // Argument is optional, no "When" keyword Console.WriteLine(ex.Message); } finally { // Must use unmanaged MessageBeep API function to beep } |
||||||||||
Namespaces | |||||||||||
Namespace Harding.Compsci.Graphics ... End Namespace ' or Namespace Harding Namespace Compsci Namespace Graphics ... End Namespace End Namespace End Namespace Import Harding.Compsci.Graphics |
namespace Harding.Compsci.Graphics { ... } // or namespace Harding { namespace Compsci { namespace Graphics { ... } } } using Harding.Compsci.Graphics; |
||||||||||
Classes / Interfaces | |||||||||||
Accessibility keywords Public Private Friend Protected Protected Friend Shared ' Inheritance Class FootballGame Inherits Competition ... End Class ' Interface definition Interface IAlarmClock ... End Interface // Extending an interface Interface IAlarmClock Inherits IClock ... End Interface // Interface implementation Class WristWatch Implements IAlarmClock, ITimer ... End Class |
Accessibility keywords public private internal protected protected internal static // Inheritance class FootballGame : Competition { ... } // Interface definition interface IAlarmClock { ... } // Extending an interface interface IAlarmClock : IClock { ... } // Interface implementation class WristWatch : IAlarmClock, ITimer { ... } |
||||||||||
Constructors / Destructors | |||||||||||
Class SuperHero Private _powerLevel As Integer Public Sub New () _powerLevel = 0 End Sub Public Sub New (ByVal powerLevel As Integer) Me._powerLevel = powerLevel End Sub Protected Overrides Sub Finalize () ' Desctructor code to free unmanaged resources MyBase.Finalize() End Sub End Class |
class SuperHero { private int _powerLevel; |
||||||||||
Objects | |||||||||||
Dim hero As SuperHero = New SuperHero With hero .Name = "SpamMan" .PowerLevel = 3 End With Dim hero2 As SuperHero = hero ' Both refer to same object hero2.Name = "WormWoman" Console.WriteLine(hero.Name) ' Prints WormWoman hero = Nothing ' Free the object If hero Is Nothing Then _ hero = New SuperHero Dim obj As Object = New SuperHero If TypeOf obj Is SuperHero Then _ Console.WriteLine("Is a SuperHero object.") |
SuperHero hero = new SuperHero(); hero.Defend("Laura Jones"); SuperHero.Rest(); // Calling static method SuperHero hero2 = hero; // Both refer to same object hero2.Name = "WormWoman"; Console.WriteLine(hero.Name); // Prints WormWoman hero = null ; // Free the object if (hero == null) hero = new SuperHero(); Object obj = new SuperHero(); if (obj is SuperHero) Console.WriteLine("Is a SuperHero object."); |
||||||||||
Structs | |||||||||||
Structure StudentRecord Public name As String Public gpa As Single Dim stu As StudentRecord = New StudentRecord("Bob", 3.5) Dim stu2 As StudentRecord = stu |
struct StudentRecord { public string name; public float gpa; public StudentRecord(string name, float gpa) { this.name = name; this.gpa = gpa; } } StudentRecord stu = new StudentRecord("Bob", 3.5f); StudentRecord stu2 = stu; |
||||||||||
Properties | |||||||||||
Private _size As Integer foo.Size += 1 |
private int _size; public int Size { get { return _size; } set { if (value < 0) _size = 0; else _size = value; } } foo.Size++; |
||||||||||
Delegates / Events | |||||||||||
Delegate Sub MsgArrivedEventHandler(ByVal message As String) Event MsgArrivedEvent As MsgArrivedEventHandler ' or to define an event which declares a delegate implicitly Event MsgArrivedEvent(ByVal message As String) AddHandler MsgArrivedEvent, AddressOf My_MsgArrivedCallback ' Won't throw an exception if obj is Nothing RaiseEvent MsgArrivedEvent("Test message") RemoveHandler MsgArrivedEvent, AddressOf My_MsgArrivedCallback Imports System.Windows.Forms Dim WithEvents MyButton As Button ' WithEvents can't be used on local variable MyButton = New Button Private Sub MyButton_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles MyButton.Click MessageBox.Show(Me, "Button was clicked", "Info", _ MessageBoxButtons.OK, MessageBoxIcon.Information) End Sub |
delegate void MsgArrivedEventHandler(string message); event MsgArrivedEventHandler MsgArrivedEvent; // Delegates must be used with events in C# using System.Windows.Forms; Button MyButton = new Button(); MyButton.Click += new System.EventHandler(MyButton_Click); private void MyButton_Click(object sender, System.EventArgs e) { MessageBox.Show(this, "Button was clicked", "Info", MessageBoxButtons.OK, MessageBoxIcon.Information); } |
||||||||||
Console I/O | |||||||||||
Special character constants vbCrLf, vbCr, vbLf, vbNewLine vbNullString vbTab vbBack vbFormFeed vbVerticalTab "" Chr(65) ' Returns 'A' Console.Write("What's your name? ") Dim name As String = Console.ReadLine() Console.Write("How old are you? ") Dim age As Integer = Val(Console.ReadLine()) Console.WriteLine("{0} is {1} years old.", name, age) ' or Console.WriteLine(name & " is " & age & " years old.") |
Escape sequences \n, \r \t \\ \" Convert.ToChar(65) // Returns 'A' - equivalent to Chr(num) in VB // or (char) 65 Console.Write("What's your name? "); string name = Console.ReadLine(); Console.Write("How old are you? "); int age = Convert.ToInt32(Console.ReadLine()); Console.WriteLine("{0} is {1} years old.", name, age); // or Console.WriteLine(name + " is " + age + " years old."); int c = Console.Read(); // Read single char Console.WriteLine(c); // Prints 65 if user enters "A" |
||||||||||
File I/O | |||||||||||
Imports System.IO Dim writer As StreamWriter = File.CreateText("c:\myfile.txt") writer.WriteLine("Out to file.") writer.Close() Dim reader As StreamReader = File.OpenText("c:\myfile.txt") Dim line As String = reader.ReadLine() While Not line Is Nothing Console.WriteLine("line=" & line) line = reader.ReadLine() End While reader.Close() Dim str As String = "Text data" Dim num As Integer = 123 Dim binWriter As New BinaryWriter (File.OpenWrite("c:\myfile.dat")) binWriter.Write(str) binWriter.Write(num) binWriter.Close() Dim binReader As New BinaryReader (File.OpenRead("c:\myfile.dat")) str = binReader.ReadString() num = binReader.ReadInt32() binReader.Close() |
using System.IO; StreamWriter writer = File.CreateText("c:\\myfile.txt"); writer.WriteLine("Out to file."); writer.Close(); StreamReader reader = File.OpenText("c:\\myfile.txt"); string line = reader.ReadLine(); while (line != null) { Console.WriteLine(line); line = reader.ReadLine(); } reader.Close(); string str = "Text data"; int num = 123; BinaryWriter binWriter = new BinaryWriter(File.OpenWrite("c:\\myfile.dat")); binWriter.Write(str); binWriter.Write(num); binWriter.Close(); BinaryReader binReader = new BinaryReader(File.OpenRead("c:\\myfile.dat")); str = binReader.ReadString(); num = binReader.ReadInt32(); binReader.Close(); |
//
[转]c#.NET和VB.NET语法的比较的更多相关文章
- ASP.NET Razor C# 和 VB 代码语法
ylbtech-.NET: ASP.NET Razor C# 和 VB 代码语法 Razor 不是一种编程语言.它是服务器端的标记语言. 1. C# 和 VB 代码语法返回顶部 Razor 同时支持 ...
- VB.NET语法小结
本人精通C#编程,VB没有开发经验,项目维护需要,特意整理了下VB语法,进行恶补.编程思想都是互通的,都是微软生的,语言大同小异. Imports System 一.(1)定义一个变量,并且初始化. ...
- VB 基础语法以及教学视频
以下是我找到的几个视频和基础知识地址,我感觉比较不错的,现在分享给大家,你们都可以去借鉴以下 视频地址1:http://www.kcch.cn/excel2007_825.html 视频地址2:htt ...
- Pascal、VB、C#、Java四种语法对照表
因为工作原因,自学会了vb后陆续接触了其它语言,在工作中经常需要与各家使用不同语言公司的开发人员做程序对接,初期特别需要一个各种语法的对照比,翻看了网络上已有高人做了整理,自己在他基础上也整理了一下, ...
- VB类模块中属性的参数——VBA中Range对象的Value属性和Value2属性的一点区别
在VB中,属性是可以有参数的,而VBA中属性使用参数非常常见.比如最常用的:Worksheet.Range("A1:A10") VB的语法,使用参数的不一定是方法,也有可能是属性 ...
- VB已死?还是会在Roslyn之下焕发新生?
(此文章同时发表在本人微信公众号"dotNET每日精华文章",欢迎右边二维码来关注.) 由于最初的ASP.NET 5测试版并未支持VB,导致社区有一种声音:觉得VB将死.今天我们就 ...
- VB.NET 定义多行文本字符的几种方式
vbCrLf 在 .NET 刚刚推出的时候,VB作为一款被微软用来"衬托"C#的语言,在许多细节设计上远不如C#方便. 比如在C#中写一个多行文本,就有各种方式: string s ...
- vba 语法
VBA语言基础 第一节 标识符 一.定义 标识符是一种标识变量.常量.过程.函数.类等语言构成单位的符号,利用它可以完成对变量.常量.过程.函数.类等的引用. 二.命名规则 1) 字母打头,由字母.数 ...
- Code First :使用Entity. Framework编程(5) ----转发 收藏
第五章 对数据库映射使用默认规则与配置 到目前为止我们已经领略了Code First的默认规则与配置对属性.类间关系的影响.在这两个领域内,Code First不仅影响模型也影响数据库.在这一章,你将 ...
随机推荐
- (一)NUnit单元测试心得
由于各种缘由,一本<.Net单元测试艺术>突然出现在了我的办公桌上,于是我的单元测试之路就此开始.通过一两个月不间断的学习,以及不断结合具体的项目做开发,再结合书上的知识对单元测试有了一些 ...
- winform中设置FormBorderStyle为None后点击任务栏自动最小化实现
在winform编程中,有时候我们可能对窗体样式需要定义,不适用系统自带的样式,这样我们可以设置FormBorderStyle属性为None.但是设置了FormBorderStyle为None后,我们 ...
- 第一个App“今日材料报价”上架,记录一下【原】
App Store地址:https://itunes.apple.com/us/app/jin-ri-cai-liao-bao-jia/id967274552?l=zh&ls=1&mt ...
- 点亮一个led
1:RS232电平:计算机串口 高电平为-12v,低电平为+12v,所以计算机与单片机进行通信的时候需要加电平转换芯片max232(高电平为-9到-12,低电平为+3到+12之间的. max232通常 ...
- LeetCode题解——Longest Palindromic Substring
题目: 给定一个字符串S,返回S中最长的回文子串.S最长为1000,且最长回文子串是唯一. 解法: ①遍历,对于每个字符,计算以它为中心的回文子串长度(长度为奇数),同时计算以它和右边相邻字符为中心的 ...
- 面向对象(class0420)
测试 交换两个变量的值 int num1 = 5;int num2=6; 通过程序交换让num1 = 6,num2=5; 求两个数的最大值 (求三个数最大值) 求1-100之间所有奇数的和 找胖子,{ ...
- 对Map按key和value分别排序
一.理论准备 Map是键值对的集合接口,它的实现类主要包括:HashMap,TreeMap,Hashtable以及LinkedHashMap等. TreeMap:基于红 ...
- Android实例-消息框(XE8+小米2)
方法一支持. 方法二与方法三都是三方单元,功能相同. 方法4与方法5报错,提示平台不支持. 第三方单元一: unit Android.JNI.Toast; // Java bridge class i ...
- TcxVerticalGrid demo
procedure TForm1.Button1Click(Sender: TObject);var row: TcxEditorRow; i,t: Integer;begin grid.ClearR ...
- jquery-ui 之draggable详解
举一个例子: <div class="box"> <div id="draggable"> <p>Drag me aroun ...