Regex para c# .net

Only letters:

Regex.IsMatch(input, @"^[a-zA-Z]+$");

Only letters and numbers:

Regex.IsMatch(input, @"^[a-zA-Z0-9]+$");

Only letters, numbers and underscore:

Regex.IsMatch(input, @"^[a-zA-Z0-9_]+$");

Puede que también hagan el trabajo

bool result = input.All(Char.IsLetter);

bool result = input.All(Char.IsLetterOrDigit);

bool result = input.All(c=>Char.IsLetterOrDigit(c) || c=='_');

public class Conexion
 {
 System.Data.SqlClient.SqlConnection conn;
        public Conexion() {
         conn = new System.Data.SqlClient.SqlConnection();
         conn.ConnectionString = "Data Source=FAMILIA-2B481F0;Initial Catalog=AdventureWorks;Integrated Security=True";
       }

 public void abrirConexion() {
 try
 {
 conn.Open();
 }
 catch (Exception ex) {
 MessageBox.Show("No pudo!!");
 }
 }

public void cerrarConexion() {
 try
 {
 conn.Close();
 }
 catch (Exception ex)
 {
 MessageBox.Show("No pudo cerrar");
 }

 }

     }

INSERTAR DATOS

public void insertarDatos(DateTime fecha)
 {
 SqlCommand cm = new SqlCommand();
 cm.Connection = conn;
 cm.CommandType = System.Data.CommandType.Text;
 //cm.CommandText = "INSERT INTO HumanResources.Department(DepartmentID, Name) values(@DepartmentID,@Name)";
 //SqlParameter par_id = cm.Parameters.Add("@DepartmentID", SqlDbType.SmallInt);
 cm.CommandText = "INSERT INTO HumanResources.Department(Name,GroupName,ModifiedDate)"+
 " values(@Name,@GroupName,@ModifiedDate)";
 SqlParameter par_name = cm.Parameters.Add("@Name", SqlDbType.NChar);
 SqlParameter par_grupo = cm.Parameters.Add("@GroupName", SqlDbType.NChar);
 //SqlParameter par_Date = cm.Parameters.Add("@ModifiedDate", SqlDbType.Date);
 cm.Parameters.AddWithValue("@ModifiedDate", fecha);
 //par_id.Value = 17;
 par_name.Value = "depto prueba";
 par_grupo.Value = "grupo prueba";
 //par_Date.Value = fecha;
 cm.ExecuteNonQuery();
 }

MODIFICAR DATOS

using System;
 using System.Data;
 using System.Data.SqlClient;

 namespace Client.Chapter_13___ADO.NET
 {
  public class UpdatingDataUsingSqlStatements
  {
  static void Main(string[] args)
  {
  SqlConnection MyConnection = new SqlConnection(@"Data Source=(local); Initial Catalog = CaseManager; Integrated Security=true");

  MyConnection.Open();

  String MyString = "UPDATE Test SET Contact = 'Lee'";
  SqlCommand MyCmd = new SqlCommand(MyString, MyConnection);

  MyCmd.ExecuteScalar();
  MyConnection.Close();
  }
  }
 }

public class MyConection {
public MyConection() {
}
public static Connection getConnection() {
Connection conn = null;
Driver d = null;
Class clase = null;

try {
clase = Class.forName(“oracle.jdbc.driver.OracleDriver”);
conn = DriverManager.getConnection(“jdbc:oracle:thin:@localhost:1521:bases”,”system”,”cracker”);
} catch (Exception ex) {
ex.printStackTrace();
}
return conn;
}
}

INSERTAR

public String inserta() {
// Add event code here…
boton1.setValue(“hola mundo!!!!”);
MyConection miConexion = new MyConection();
Connection conn = miConexion.getConnection();
try{
Statement st = conn.createStatement();
PreparedStatement ps = conn.prepareStatement(“INSERT INTO estudiante VALUES(?,?)”);
//st.execute(“INSERT INTO estudiante VALUES(“+getT_id().getValue().toString()+”,’”+getT_nombre().getValue().toString()+”‘)”);
//st.close();
ps.setString(1,getT_id().getValue().toString());
ps.setString(2,getT_nombre().getValue().toString());
ps.executeUpdate();
ps.close();
conn.close();
}catch(Exception e){e.printStackTrace();}

return null;
}

CONSULTAS

public String consulta() {
// Add event code here…
b_buscar.setValue(“Buscando…”);
MyConection miConexion = new MyConection();
Connection conn= miConexion.getConnection();
Estudiante estudiante;
try{
Statement st = conn.createStatement();
ResultSet rs = st.executeQuery(“select * from estudiante”);
while(rs.next()){
estudiante = new Estudiante(rs.getLong(“id”),rs.getString(“nombre”));
getListaEstudiantes().add(estudiante);
}

}catch(Exception ex){
ex.printStackTrace();
}
return null;
}

MODIFICAR

public String ModificarNombre() {
// Add event code here…
MyConection miConexion = new MyConection();
Connection conn = miConexion.getConnection();
String nombreNuevo = t_nombre.getValue().toString();
String idEst = t_id.getValue().toString();

String consulta =”UPDATE estudiante SET nombre=’”+nombreNuevo+”‘ WHERE id=”+idEst;
try{
PreparedStatement pst = conn.prepareStatement(consulta);
pst.executeUpdate();
pst.close();

}catch(Exception ex){
ex.printStackTrace();
}
System.out.println(“modificando!”);
return null;
}