[分享]C#入门代码集25个

zzp139

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[0];

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[0];

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


[STAThread]
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


[STAThread]
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
{
[WebMethod()]
public string StringFromWebService()
{
return "This is a string from web service.";
}
}

autumnwinter

谢谢楼主!

好东西!值得学习