C#常用代码

1、http://www.cnblogs.com/me-sa/articles/548636.html

一、从控制台读取东西代码片断：
  4using System;
  5
  6class TestReadConsole
  7{
  8    public static void Main()
  9    {
 10        Console.Write(Enter your name:);
 11        string strName = Console.ReadLine();
 12        Console.WriteLine( Hi + strName);
 13    }
 14}
 15二、读文件代码片断：
 16using System; 
 17using System.IO; 
 18
 19public class TestReadFile 
 20{ 
 21    public static void Main(String[] args) 
 22    { 
 23        // Read text file C:\temp\test.txt 
 24        FileStream fs = new FileStream(@c:\temp\test.txt , FileMode.Open, FileAccess.Read); 
 25        StreamReader sr = new StreamReader(fs);  
 26        
 27        String line=sr.ReadLine();
 28        while (line!=null)
 29        {
 30            Console.WriteLine(line);
 31            line=sr.ReadLine();
 32        }   
 33        
 34        sr.Close();
 35        fs.Close();
 36    } 
 37} 
 38三、写文件代码：
 39using System; 
 40using System.IO; 
 41
 42public class TestWriteFile 
 43{ 
 44    public static void Main(String[] args) 
 45    { 
 46        // Create a text file C:\temp\test.txt 
 47        FileStream fs = new FileStream(@c:\temp\test.txt , FileMode.OpenOrCreate, FileAccess.Write); 
 48        StreamWriter sw = new StreamWriter(fs); 
 49        // Write to the file using StreamWriter class 
 50        sw.BaseStream.Seek(0, SeekOrigin.End); 
 51        sw.WriteLine( First Line ); 
 52        sw.WriteLine( Second Line); 
 53        sw.Flush(); 
 54    } 
 55} 
 56四、拷贝文件：
 57using System;
 58using System.IO;
 59
 60class TestCopyFile
 61{
 62    public static void Main()
 63    {
 64        File.Copy(c:\\temp\\source.txt, C:\\temp\\dest.txt );  
 65    }
 66}
 67五、移动文件：
 68using System;
 69using System.IO;
 70
 71class TestMoveFile
 72{
 73    public static void Main()
 74    {
 75        File.Move(c:\\temp\\abc.txt, C:\\temp\\def.txt );  
 76    }
 77}
 78六、使用计时器：
 79using System;
 80using System.Timers;
 81
 82class TestTimer
 83{
 84    public static void Main()
 85    {
 86        Timer timer = new Timer();
 87        timer.Elapsed += new ElapsedEventHandler( DisplayTimeEvent );
 88        timer.Interval = 1000;
 89        timer.Start();
 90        timer.Enabled = true;
 91
 92        while ( Console.Read() != 'q' )
 93        {
 94
 95        }
 96    }
 97
 98    public static void DisplayTimeEvent( object source, ElapsedEventArgs e )
 99    {
100        Console.Write(\r{0}, DateTime.Now);
101    }
102}
103七、调用外部程序：
104class Test 
105{ 
106    static void Main(string[] args) 
107    { 
108        System.Diagnostics.Process.Start(notepad.exe); 
109    } 
110}
111
112ADO.NET方面的：
113八、连接Access数据库：
114using System;
115using System.Data;
116using System.Data.OleDb;
117
118class TestADO
119{
120    static void Main(string[] args)
121    {
122        string strDSN = Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\\test.mdb;
123        string strSQL = SELECT * FROM employees ;
124
125        OleDbConnection conn = new OleDbConnection(strDSN);
126        OleDbCommand cmd = new OleDbCommand( strSQL, conn );
127        OleDbDataReader reader = null;
128        try
129        {
130            conn.Open();
131            reader = cmd.ExecuteReader();
132            while (reader.Read() )
133            {
134                Console.WriteLine(First Name:{0}, Last Name:{1}, reader[FirstName], reader[LastName]);
135            }
136        }
137        catch (Exception e)
138        {
139            Console.WriteLine(e.Message);
140        }
141        finally
142        {
143            conn.Close();
144        }
145    }
146} 
147九、连接SQL Server数据库：
148using System;
149using System.Data.SqlClient;
150
151public class TestADO
152{
153    public static void Main()
154    {
155        SqlConnection conn = new SqlConnection(Data Source=localhost; Integrated Security=SSPI; Initial Catalog=pubs);
156        SqlCommand  cmd = new SqlCommand(SELECT * FROM employees, conn);
157        try
158        {        
159            conn.Open();
160
161            SqlDataReader reader = cmd.ExecuteReader();            
162            while (reader.Read())
163            {
164                Console.WriteLine(First Name: {0}, Last Name: {1}, reader.GetString(0), reader.GetString(1));
165            }
166        
167            reader.Close();
168            conn.Close();
169        }
170        catch(Exception e)
171        {
172            Console.WriteLine(Exception Occured -->> {0},e);
173        }        
174    }
175}
176十、从SQL内读数据到XML：
177using System;
178using System.Data;
179using System.Xml;
180using System.Data.SqlClient; 
181using System.IO; 
182
183public class TestWriteXML
184{ 
185    public static void Main()
186    { 
187
188        String strFileName=c:/temp/output.xml;
189
190        SqlConnection conn = new SqlConnection(server=localhost;uid=sa;pwd=;database=db);
191
192        String strSql = SELECT FirstName, LastName FROM employees; 
193
194        SqlDataAdapter adapter = new SqlDataAdapter(); 
195
196        adapter.SelectCommand = new SqlCommand(strSql,conn);
197
198        // Build the DataSet
199        DataSet ds = new DataSet();
200
201        adapter.Fill(ds, employees);
202
203        // Get a FileStream object
204        FileStream fs = new FileStream(strFileName,FileMode.OpenOrCreate,FileAccess.Write);
205
206        // Apply the WriteXml method to write an XML document
207        ds.WriteXml(fs);
208
209        fs.Close();
210
211    }
212}
213十一、用ADO添加数据到数据库中：
214using System;
215using System.Data;   
216using System.Data.OleDb;   
217
218class TestADO
219{  
220    static void Main(string[] args)  
221    {  
222        string strDSN = Provider=Microsoft.Jet.OLEDB.4.0;DataSource=c:\test.mdb;  
223        string strSQL = INSERT INTO Employee(FirstName, LastName) VALUES('FirstName', 'LastName') ;  
224                   
225        // create Objects of ADOConnection and ADOCommand   
226        OleDbConnection conn = new OleDbConnection(strDSN);  
227        OleDbCommand cmd = new OleDbCommand( strSQL, conn );  
228        try  
229        {  
230            conn.Open();  
231            cmd.ExecuteNonQuery();  
232        }  
233        catch (Exception e)  
234        {  
235            Console.WriteLine(Oooops. I did it again:\n{0}, e.Message);  
236        }  
237        finally  
238        {  
239            conn.Close();  
240        }          
241    } 
242}  
243十二、使用OLEConn连接数据库：
244using System;
245using System.Data;   
246using System.Data.OleDb;   
247
248class TestADO
249{  
250    static void Main(string[] args)  
251    {  
252        string strDSN = Provider=Microsoft.Jet.OLEDB.4.0;DataSource=c:\test.mdb;  
253        string strSQL = SELECT * FROM employee ;  
254
255        OleDbConnection conn = new OleDbConnection(strDSN);
256        OleDbDataAdapter cmd = new OleDbDataAdapter( strSQL, conn ); 
257
258        conn.Open();
259        DataSet ds = new DataSet();
260        cmd.Fill( ds, employee );
261        DataTable dt = ds.Tables[0];
262
263        foreach( DataRow dr in dt.Rows )
264        {
265            Console.WriteLine(First name: + dr[FirstName].ToString() + Last name: + dr[LastName].ToString());
266        }
267        conn.Close();  
268    } 
269}  
270十三、读取表的属性：
271using System;
272using System.Data;   
273using System.Data.OleDb;   
274
275class TestADO
276{  
277    static void Main(string[] args)  
278    {  
279        string strDSN = Provider=Microsoft.Jet.OLEDB.4.0;DataSource=c:\test.mdb;  
280        string strSQL = SELECT * FROM employee ;  
281
282        OleDbConnection conn = new OleDbConnection(strDSN);
283        OleDbDataAdapter cmd = new OleDbDataAdapter( strSQL, conn ); 
284
285        conn.Open();
286        DataSet ds = new DataSet();
287        cmd.Fill( ds, employee );
288        DataTable dt = ds.Tables[0];
289
290        Console.WriteLine(Field Name DataType Unique AutoIncrement AllowNull);
291        Console.WriteLine(==================================================================);
292        foreach( DataColumn dc in dt.Columns )
293        {
294            Console.WriteLine(dc.ColumnName+ , +dc.DataType + ,+dc.Unique + ,+dc.AutoIncrement+ ,+dc.AllowDBNull );
295        }
296        conn.Close();  
297    } 
298} 
299
300ASP.NET方面的
301十四、一个ASP.NET程序：
302<%@ Page Language=C# %>
303<script runat=server>
304   
305    void Button1_Click(Object sender, EventArgs e) 
306    {
307        Label1.Text=TextBox1.Text;
308    }
309
310</script>
311<html>
312<head>
313</head>
314<body>
315    <form runat=server>
316        <p>
317            <br />
318            Enter your name: <asp:TextBox id=TextBox1 runat=server></asp:TextBox>
319        </p>
320        <p>
321            <b><asp:Label id=Label1 runat=server Width=247px></asp:Label></b>
322        </p>
323        <p>
324            <asp:Button id=Button1 onclick=Button1_Click runat=server Text=Submit></asp:Button>
325        </p>
326    </form>
327</body>
328</html>
329
330WinForm开发：
331十五、一个简单的WinForm程序：
332using System;
333using System.Drawing;
334using System.Collections;
335using System.ComponentModel;
336using System.Windows.Forms;
337using System.Data;
338
339
340public class SimpleForm : System.Windows.Forms.Form
341{
342
343    private System.ComponentModel.Container components = null;
344    private System.Windows.Forms.Button button1;
345    private System.Windows.Forms.TextBox textBox1;
346    public SimpleForm()
347    {
348        InitializeComponent();
349    }
350
351    protected override void Dispose( bool disposing )
352    {
353        if( disposing )
354        {
355            if (components != null)
356            {
357                components.Dispose();
358            }
359        }
360        base.Dispose( disposing );
361    }
362
363    Windows Form Designer generated code
407
408    [STAThread]
409    static void Main()
410    {
411        Application.Run(new SimpleForm());
412    } 
413}
414十六、运行时显示自己定义的图标：
415//load icon and set to form
416System.Drawing.Icon ico = new System.Drawing.Icon(@c:\temp\app.ico);
417this.Icon = ico;
418十七、添加组件到ListBox中：
419private void Form1_Load(object sender, System.EventArgs e)
420{
421    string str = First item;
422    int i = 23;
423    float flt = 34.98f; 
424    listBox1.Items.Add(str);
425    listBox1.Items.Add(i.ToString());
426    listBox1.Items.Add(flt.ToString());
427    listBox1.Items.Add(Last Item in the List Box);
428} 
429
430网络方面的：
431十八、取得IP地址：
432using System;
433using System.Net;
434
435class GetIP
436{
437     public static void Main()
438     {
439         IPHostEntry ipEntry = Dns.GetHostByName (localhost);
440         IPAddress [] IpAddr = ipEntry.AddressList;
441         for (int i = 0; i < IpAddr.Length; i++)
442         { 
443             Console.WriteLine (IP Address {0}: {1} , i, IpAddr.ToString ());
444         }
445    }
446}
447十九、取得机器名称：
448using System;
449using System.Net;
450
451class GetIP
452{
453    public static void Main()
454    {
455          Console.WriteLine (Host name : {0}, Dns.GetHostName());
456    }
457}
458二十、发送邮件：
459using System;
460using System.Web;
461using System.Web.Mail;
462
463public class TestSendMail
464{
465    public static void Main()
466    {
467        try
468        {
469            // Construct a new mail message 
470            MailMessage message = new MailMessage();
471            message.From = from@domain.com;
472            message.To   =  pengyun@cobainsoft.com;
473            message.Cc   = ;
474            message.Bcc  = ;
475            message.Subject = Subject;
476            message.Body = Content of message;
477            
478            //if you want attach file with this mail, add the line below
479            message.Attachments.Add(new MailAttachment(c:\\attach.txt, MailEncoding.Base64));
480  
481            // Send the message
482            SmtpMail.Send(message);  
483            System.Console.WriteLine(Message has been sent);
484        }
485
486        catch(Exception ex)
487        {
488            System.Console.WriteLine(ex.Message.ToString());
489        }
490
491    }
492}
493二十一、根据IP地址得出机器名称：
494using System;
495using System.Net;
496
497class ResolveIP
498{
499     public static void Main()
500     {
501         IPHostEntry ipEntry = Dns.Resolve(172.29.9.9);
502         Console.WriteLine (Host name : {0}, ipEntry.HostName);         
503     }
504}
505
506GDI+方面的：
507二十二、GDI+入门介绍：
508using System;
509using System.Drawing;
510using System.Collections;
511using System.ComponentModel;
512using System.Windows.Forms;
513using System.Data;
514
515public class Form1 : System.Windows.Forms.Form
516{
517    private System.ComponentModel.Container components = null;
518
519    public Form1()
520    {
521        InitializeComponent();
522    }
523
524    protected override void Dispose( bool disposing )
525    {
526        if( disposing )
527        {
528            if (components != null) 
529            {
530                components.Dispose();
531            }
532        }
533        base.Dispose( disposing );
534    }
535
536    Windows Form Designer generated code
546
547    [STAThread]
548    static void Main() 
549    {
550        Application.Run(new Form1());
551    }
552
553    private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
554    {
555        Graphics g=e.Graphics;
556        g.DrawLine(new Pen(Color.Blue),10,10,210,110);
557        g.DrawRectangle(new Pen(Color.Red),10,10,200,100);
558        g.DrawEllipse(new Pen(Color.Yellow),10,150,200,100);
559    }
560}
561
562XML方面的：
563二十三、读取XML文件：
564using System;
565using System.Xml;  
566
567class TestReadXML
568{
569    public static void Main()
570    {
571        
572        XmlTextReader reader  = new XmlTextReader(C:\\test.xml);
573        reader.Read();
574        
575        while (reader.Read())
576        {            
577            reader.MoveToElement();
578            Console.WriteLine(XmlTextReader Properties Test);
579            Console.WriteLine(===================);  
580
581            // Read this properties of element and display them on console
582            Console.WriteLine(Name: + reader.Name);
583            Console.WriteLine(Base URI: + reader.BaseURI);
584            Console.WriteLine(Local Name: + reader.LocalName);
585            Console.WriteLine(Attribute Count: + reader.AttributeCount.ToString());
586            Console.WriteLine(Depth: + reader.Depth.ToString());
587            Console.WriteLine(Line Number: + reader.LineNumber.ToString());
588            Console.WriteLine(Node Type: + reader.NodeType.ToString());
589            Console.WriteLine(Attribute Count: + reader.Value.ToString());
590        }        
591    }               
592} 
593二十四、写XML文件：
594using System; 
595using System.Xml; 
596
597public class TestWriteXMLFile 
598{ 
599    public static int Main(string[] args) 
600    { 
601        try 
602        {  
603            // Creates an XML file is not exist 
604            XmlTextWriter writer = new XmlTextWriter(C:\\temp\\xmltest.xml, null); 
605            // Starts a new document 
606            writer.WriteStartDocument(); 
607            //Write comments 
608            writer.WriteComment(Commentss: XmlWriter Test Program); 
609            writer.WriteProcessingInstruction(Instruction,Person Record); 
610            // Add elements to the file 
611            writer.WriteStartElement(p, person, urn:person); 
612            writer.WriteStartElement(LastName,); 
613            writer.WriteString(Chand); 
614            writer.WriteEndElement(); 
615            writer.WriteStartElement(FirstName,); 
616            writer.WriteString(Mahesh); 
617            writer.WriteEndElement(); 
618            writer.WriteElementInt16(age,, 25); 
619            // Ends the document 
620            writer.WriteEndDocument(); 
621        } 
622        catch (Exception e) 
623        {  
624            Console.WriteLine (Exception: {0}, e.ToString()); 
625        } 
626        return 0; 
627    } 
628} 
629
630Web Service方面的：
631二十五、一个Web Service的小例子：
632<% @WebService Language=C# Class=TestWS %>
633
634using System.Web.Services;
635
636public class TestWS : System.Web.Services.WebService
637{
638    [WebMethod()]
639    public string StringFromWebService()
640    {
641        return This is a string from web service.;
642    }
643}
644