[分享]C#入门代码集25个
一、从控制台读取东西代码片断：using System;
class TestReadConsole
{
public static void Main()
{
Console.Write("Enter your name:");
string strName = Console.ReadLine();
Console.WriteLine(" Hi "+ strName);
}
}
二、读文件代码片断：
using System;
using System.IO;
public class TestReadFile
{
public static void Main(String[] args)
{
// Read text file C:\temp\test.txt
FileStream fs = new FileStream(@"c:\temp\test.txt" , FileMode.Open, FileAccess.Read);
StreamReader sr = new StreamReader(fs);
String line=sr.ReadLine();
while (line!=null)
{
Console.WriteLine(line);
line=sr.ReadLine();
}
sr.Close();
fs.Close();
}
}
三、写文件代码：
using System;
using System.IO;
public class TestWriteFile
{
public static void Main(String[] args)
{
// Create a text file C:\temp\test.txt
FileStream fs = new FileStream(@"c:\temp\test.txt" , FileMode.OpenOrCreate, FileAccess.Write);
StreamWriter sw = new StreamWriter(fs);
// Write to the file using StreamWriter class
sw.BaseStream.Seek(0, SeekOrigin.End);
sw.WriteLine(" First Line ");
sw.WriteLine(" Second Line");
sw.Flush();
}
}
四、拷贝文件：
using System;
using System.IO;
class TestCopyFile
{
public static void Main()
{
File.Copy("c:\\temp\\source.txt", "C:\\temp\\dest.txt" );
}
}
五、移动文件：
using System;
using System.IO;
class TestMoveFile
{
public static void Main()
{
File.Move("c:\\temp\\abc.txt", "C:\\temp\\def.txt" );
}
}
六、使用计时器：
using System;
using System.Timers;
class TestTimer
{
public static void Main()
{
Timer timer = new Timer();
timer.Elapsed += new ElapsedEventHandler( DisplayTimeEvent );
timer.Interval = 1000;
timer.Start();
timer.Enabled = true;
while ( Console.Read() != 'q' )
{
}
}
public static void DisplayTimeEvent( object source, ElapsedEventArgs e )
{
Console.Write("\r{0}", DateTime.Now);
}
}
七、调用外部程序：
class Test
{
static void Main(string[] args)
{
System.Diagnostics.Process.Start("notepad.exe");
}
}
ADO.NET方面的：
八、连接Access数据库：
using System;
using System.Data;
using System.Data.OleDb;
class TestADO
{
static void Main(string[] args)
{
string strDSN = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\\test.mdb";
string strSQL = "SELECT * FROM employees" ;
OleDbConnection conn = new OleDbConnection(strDSN);
OleDbCommand cmd = new OleDbCommand( strSQL, conn );
OleDbDataReader reader = null;
try
{
conn.Open();
reader = cmd.ExecuteReader();
while (reader.Read() )
{
Console.WriteLine("First Name:{0}, Last Name:{1}", reader["FirstName"], reader["LastName"]);
}
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
finally
{
conn.Close();
}
}
}
九、连接SQL Server数据库：
using System;
using System.Data.SqlClient;
public class TestADO
{
public static void Main()
{
SqlConnection conn = new SqlConnection("Data Source=localhost; Integrated Security=SSPI; Initial Catalog=pubs");
SqlCommand cmd = new SqlCommand("SELECT * FROM employees", conn);
try
{
conn.Open();
SqlDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
Console.WriteLine("First Name: {0}, Last Name: {1}", reader.GetString(0), reader.GetString(1));
}
reader.Close();
conn.Close();
}
catch(Exception e)
{
Console.WriteLine("Exception Occured -->> {0}",e);
}
}
}
十、从SQL内读数据到XML：
using System;
using System.Data;
using System.Xml;
using System.Data.SqlClient;
using System.IO;
public class TestWriteXML
{
public static void Main()
{
String strFileName="c:/temp/output.xml";
SqlConnection conn = new SqlConnection("server=localhost;uid=sa;pwd=;database=db");
String strSql = "SELECT FirstName, LastName FROM employees";
SqlDataAdapter adapter = new SqlDataAdapter();
adapter.SelectCommand = new SqlCommand(strSql,conn);
// Build the DataSet
DataSet ds = new DataSet();
adapter.Fill(ds, "employees");
// Get a FileStream object
FileStream fs = new FileStream(strFileName,FileMode.OpenOrCreate,FileAccess.Write);
// Apply the WriteXml method to write an XML document
ds.WriteXml(fs);
fs.Close();
}
}
十一、用ADO添加数据到数据库中：
using System;
using System.Data;
using System.Data.OleDb;
class TestADO
{
static void Main(string[] args)
{
string strDSN = "Provider=Microsoft.Jet.OLEDB.4.0;DataSource=c:\test.mdb";
string strSQL = "INSERT INTO Employee(FirstName, LastName) valueS('FirstName', 'LastName')" ;
// create Objects of ADOConnection and ADOCommand
OleDbConnection conn = new OleDbConnection(strDSN);
OleDbCommand cmd = new OleDbCommand( strSQL, conn );
try
{
conn.Open();
cmd.ExecuteNonQuery();
}
catch (Exception e)
{
Console.WriteLine("Oooops. I did it again:\n{0}", e.Message);
}
finally
{
conn.Close();
}
}
}
十二、使用OLEConn连接数据库：
using System;
using System.Data;
using System.Data.OleDb;
class TestADO
{
static void Main(string[] args)
{
string strDSN = "Provider=Microsoft.Jet.OLEDB.4.0;DataSource=c:\test.mdb";
string strSQL = "SELECT * FROM employee" ;
OleDbConnection conn = new OleDbConnection(strDSN);
OleDbDataAdapter cmd = new OleDbDataAdapter( strSQL, conn );
conn.Open();
DataSet ds = new DataSet();
cmd.Fill( ds, "employee" );
DataTable dt = ds.Tables;
foreach( DataRow dr in dt.Rows )
{
Console.WriteLine("First name: "+ dr["FirstName"].ToString() + " Last name: "+ dr["LastName"].ToString());
}
conn.Close();
}
}
十三、读取表的属性：
using System;
using System.Data;
using System.Data.OleDb;
class TestADO
{
static void Main(string[] args)
{
string strDSN = "Provider=Microsoft.Jet.OLEDB.4.0;DataSource=c:\test.mdb";
string strSQL = "SELECT * FROM employee" ;
OleDbConnection conn = new OleDbConnection(strDSN);
OleDbDataAdapter cmd = new OleDbDataAdapter( strSQL, conn );
conn.Open();
DataSet ds = new DataSet();
cmd.Fill( ds, "employee" );
DataTable dt = ds.Tables;
Console.WriteLine("Field Name DataType Unique AutoIncrement AllowNull");
Console.WriteLine("==================================================================");
foreach( DataColumn dc in dt.Columns )
{
Console.WriteLine(dc.ColumnName+" , "+dc.DataType +" ,"+dc.Unique +" ,"+dc.AutoIncrement+" ,"+dc.AllowDBNull );
}
conn.Close();
}
}
ASP.NET方面的
十四、一个ASP.NET程序：
<%@Page Language="C#" %><script runat="server"> void Button1_Click(Objectsender, EventArgs e){Label1.Text=TextBox1.Text;} </script> <html> <head> </head> <body> <form runat="server"> <p> <br /> Enteryour name: <asp:TextBox id="TextBox1" runat="server"></asp:TextBox> </p> <p> <b><asp:Label id="Label1" runat="server" Width="247px"></asp:Label></b> </p> <p> <asp:Button id="Button1" onclick="Button1_Click" runat="server" Text="Submit"></asp:Button></p> </form> </body> </html>
WinForm开发：
十五、一个简单的WinForm程序：
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
public class SimpleForm : System.Windows.Forms.Form
{
private System.ComponentModel.Container components = null;
private System.Windows.Forms.Button button1;
private System.Windows.Forms.TextBox textBox1;
public SimpleForm()
{
InitializeComponent();
}
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}
#region Windows Form Designer generated code
private void InitializeComponent()
{
this.components = new System.ComponentModel.Container();
this.Size = new System.Drawing.Size(300,300);
this.Text = "Form1";
this.button1 = new System.Windows.Forms.Button();
this.textBox1 = new System.Windows.Forms.TextBox();
this.SuspendLayout();
//
// button1
//
this.button1.Location = new System.Drawing.Point(8, 16);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(80, 24);
this.button1.TabIndex = 0;
this.button1.Text = "button1";
//
// textBox1
//
this.textBox1.Location = new System.Drawing.Point(112, 16);
this.textBox1.Name = "textBox1";
this.textBox1.Size = new System.Drawing.Size(160, 20);
this.textBox1.TabIndex = 1;
this.textBox1.Text = "textBox1";
//
// Form1
//
this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
this.ClientSize = new System.Drawing.Size(292, 273);
this.Controls.AddRange(new System.Windows.Forms.Control[] {
this.textBox1,
this.button1});
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayout(false);
}
#endregion
static void Main()
{
Application.Run(new SimpleForm());
}
}
十六、运行时显示自己定义的图标：
//load icon and set to form
System.Drawing.Icon ico = new System.Drawing.Icon(@"c:\temp\app.ico");
this.Icon = ico;
十七、添加组件到ListBox中：
private void Form1_Load(object sender, System.EventArgs e)
{
string str = "First item";
int i = 23;
float flt = 34.98f;
listBox1.Items.Add(str);
listBox1.Items.Add(i.ToString());
listBox1.Items.Add(flt.ToString());
listBox1.Items.Add("Last Item in the List Box");
}
网络方面的：
十八、取得IP地址：
using System;
using System.Net;
class GetIP
{
public static void Main()
{
IPHostEntry ipEntry = Dns.GetHostByName ("localhost");
IPAddress [] IpAddr = ipEntry.AddressList;
for (int i = 0; i < IpAddr.Length; i++)
{
Console.WriteLine ("IP Address {0}: {1} ", i, IpAddr.ToString ());
}
}
}
十九、取得机器名称：
using System;
using System.Net;
class GetIP
{
public static void Main()
{
Console.WriteLine ("Host name : {0}", Dns.GetHostName());
}
}
二十、发送邮件：
using System;
using System.Web;
using System.Web.Mail;
public class TestSendMail
{
public static void Main()
{
try
{
// Construct a new mail message
MailMessage message = new MailMessage();
message.From = "from@domain.com";
message.To = "pengyun@cobainsoft.com";
message.Cc = "";
message.Bcc = "";
message.Subject = "Subject";
message.Body = "Content of message";
//if you want attach file with this mail, add the line below
message.Attachments.Add(new MailAttachment("c:\\attach.txt", MailEncoding.Base64));
// Send the message
SmtpMail.Send(message);
System.Console.WriteLine("Message has been sent");
}
catch(Exception ex)
{
System.Console.WriteLine(ex.Message.ToString());
}
}
}
二十一、根据IP地址得出机器名称：
using System;
using System.Net;
class ResolveIP
{
public static void Main()
{
IPHostEntry ipEntry = Dns.Resolve("172.29.9.9");
Console.WriteLine ("Host name : {0}", ipEntry.HostName);
}
}
GDI+方面的：
二十二、GDI+入门介绍：
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
public class Form1 : System.Windows.Forms.Form
{
private System.ComponentModel.Container components = null;
public Form1()
{
InitializeComponent();
}
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}
#region Windows Form Designer generated code
private void InitializeComponent()
{
this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
this.ClientSize = new System.Drawing.Size(292, 273);
this.Name = "Form1";
this.Text = "Form1";
this.Paint += new System.Windows.Forms.PaintEventHandler(this.Form1_Paint);
}
#endregion
static void Main()
{
Application.Run(new Form1());
}
private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
Graphics g=e.Graphics;
g.DrawLine(new Pen(Color.Blue),10,10,210,110);
g.DrawRectangle(new Pen(Color.Red),10,10,200,100);
g.DrawEllipse(new Pen(Color.Yellow),10,150,200,100);
}
}
XML方面的：
二十三、读取XML文件：
using System;
using System.Xml;
class TestReadXML
{
public static void Main()
{
XmlTextReader reader = new XmlTextReader("C:\\test.xml");
reader.Read();
while (reader.Read())
{
reader.MoveToElement();
Console.WriteLine("XmlTextReader Properties Test");
Console.WriteLine("===================");
// Read this properties of element and display them on console
Console.WriteLine("Name:" + reader.Name);
Console.WriteLine("Base URI:" + reader.BaseURI);
Console.WriteLine("Local Name:" + reader.LocalName);
Console.WriteLine("Attribute Count:" + reader.AttributeCount.ToString());
Console.WriteLine("Depth:" + reader.Depth.ToString());
Console.WriteLine("Line Number:" + reader.LineNumber.ToString());
Console.WriteLine("Node Type:" + reader.NodeType.ToString());
Console.WriteLine("Attribute Count:" + reader.value.ToString());
}
}
}
二十四、写XML文件：
using System;
using System.Xml;
public class TestWriteXMLFile
{
public static int Main(string[] args)
{
try
{
// Creates an XML file is not exist
XmlTextWriter writer = new XmlTextWriter("C:\\temp\\xmltest.xml", null);
// Starts a new document
writer.WriteStartDocument();
//Write comments
writer.WriteComment("Commentss: XmlWriter Test Program");
writer.WriteProcessingInstruction("Instruction","Person Record");
// Add elements to the file
writer.WriteStartElement("p", "person", "urn:person");
writer.WriteStartElement("LastName","");
writer.WriteString("Chand");
writer.WriteEndElement();
writer.WriteStartElement("FirstName","");
writer.WriteString("Mahesh");
writer.WriteEndElement();
writer.WriteElementInt16("age","", 25);
// Ends the document
writer.WriteEndDocument();
}
catch (Exception e)
{
Console.WriteLine ("Exception: {0}", e.ToString());
}
return 0;
}
}
Web Service方面的：
二十五、一个Web Service的小例子：
using System.Web.Services;
public class TestWS : System.Web.Services.WebService
{
public string StringFromWebService()
{
return "This is a string from web service.";
}
} 谢谢楼主!
好东西!值得学习
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