c#经典实例（含9个实例）

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(Object sender, EventArgs e) { Label1.Text=TextBox1.Text; } </script> <html> <head> </head>