General small things: 1. Reading something from the console: USING SYSTEM;
Class testreadconsole {public static void main () {console.write ("Enter your name:"); string strname = console.readline (); console.writeline ("hi" strname);}} 2, read file code snippet : Use system; use 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 ();}} 3, write file code: use system; use 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 ();}} 4, copy file: use system; use system;
Class testcopyfile {public static void main () {file.copy ("c: //temp//source.txt");}} 5, mobile files: USING SYSTEM Using system.io;
Class testmovefile {public static void main () {file.move ("c: //temp//Abc.txt");}} 6, usage timer: 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);}} seven, call external programs: class test {static void main (string [] args) { System.diagnostics.Process.Start ("NOTEPAD.EXE");}} ADO.NET: Eight, Connect Access Database: Using System; Using System.Data; Using System.Data.OLDB;
Class testo {static void main (string "args) {string strdsn =" provcer = microsoft.jet.OLDB.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 ();}}} nine, connected to SQL Server database: use system; use system; public class testo {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}} {0}", e);}}} ten, from SQL Read data to xml: use system.data; use system.xml; use system.data.sqlclient; use 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 ();
}} 11, add data to the database with ADO: use system; use system.data; use 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 (); (Exception E) {Console.Writeline ("OOOOPS. I DID IT AGAIN: / N {0}", E.MESSAGE);} finally {conn.close ();}}} Oleconn connection database: using system; 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];
"DATAROW DR IN DT.ROWS) {Console.Writeline (" first name: " DR [" firstname "]. TOSTRING () " Last Name: " DR [" Lastname "]. TOSTRING ());} Conn.close ();}} 13. The properties of the read table: use system; use system.data; use system.data.oledb;
Class testo {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. Dattype "," DC.AutoInCrement "," DC.AllowdBnull);} () (); ();}} ASP.NET Fourteen, an ASP.NET program: <% @ page language = "c #"%>
