How do windows applications connect to the database?

jy156888

Brothers! Help!

fredzb

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

namespace news.common
{
 / **
  * -----------------
  * Database connection / operation class
  * ----------------
  * /

 public class DBClass
 {
  / * ---- Global variable definition ------ * /

  private SqlConnection conn;
  private SqlCommand comm;
  public SqlDataReader dr;
  public DataSet ds;
  public SqlDataAdapter dad;
  private string sql;
  private string connStr; / * database connection string * /
  private string errInfo = "";
  / * ---------------------- * /

  public DBClass ()
  {
  }
  / * Database operation exception information read-only attribute * /
  public string ErrInfo
  {
   get
   {
    return errInfo;
   }
  }
  / * Sql statement to operate * /
  public string Sql
  {
   get {
    return sql;
   }
   set {
    sql = value;
   }
  }
  / * Database link string * /
  public string ConnStr
  {
   get
   {
    return connStr;
   }
   set
   {
    connStr = value;
   }
  }
  private void connDb ()
  {
   conn = new SqlConnection (connStr);
   try
   {
    conn.Open ();
   }
   catch (SqlException e)
   {
    for (int i = 0; i <e.Errors.Count; i ++)
    {
     errInfo + = "Error serial number:" + i + "\n" +
                       "Error message:" + e.Errors [i] .Message + "\n" +
                       "Error source:" + e.Errors [i] .Source + "\n" +
                       "Procedure:" + e.Errors [i] .Procedure;
    }
    conn.Close ();
   }
  }
  / * For form binding * /
  public void dataView ()
  {
   connDb ();
   dad = new SqlDataAdapter (sql, conn);
   ds = new DataSet ();
   dad.Fill (ds);
   DataView dv = new DataView (ds.Tables [0]);
  }
  / * Execute SQL statements and return results * /
  public void readerData ()
  {
   connDb ();
   comm = new SqlCommand (sql, conn);
   dr = comm.ExecuteReader ();
  }
  / * Execute SQL statement without returning results * /
  public void exeSql ()
  {
   connDb ();
   comm = new SqlCommand (sql, conn);
   comm.ExecuteNonQuery ();
  }
  / * Close link * /
  public void clear ()
  {
   conn.Close ();
  }
 }
}

wenmy715

Same as the web

string connStr = "....";
SqlConnection conn = new SqlConnection (connStr);
string sqlStr = "...";
SqlCommand cmd = new SqlCommand (sqlStr, conn);
SqlDataAdapter da = new SqlDataAdapter (cmd);
.....

suyanlong

The second floor is just the sql server.

If it is Access
using System.Data.OleDb;
 public static OleDbConnection createOleconn () // Connection Access
  {
     string strConnection = "Provider = Microsoft.Jet.OleDb.4.0;";
     strConnection + = @ "Data Source = E:\net\datagridTest\CP2SysTempDB.mdb";
    // strConnection + = "Data Source =";
    // strConnection + = Server.MapPath ("CP2SysTempDB.mdb");


     OleDbConnection olconn = new OleDbConnection (strConnection);
     return olconn;
  }

kalian2000

First ask what database ..

kalian2000

Write an example of binding DataGridView:

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

SqlConnection con = new SqlConnection ("server = .; database = student; uid = sa; pwd = 0421");
SqlDataAdapter sda = new SqlDataAdapter ("select * from studentDetails", con);
DataSet ds = new DataSet ();
sda.Fill (ds, "student");
this.DataGridView.DataSource = ds.Tables ["student"];

jy156888

Access, I want to use DataGrid binding! How to do it

kalian2000

using System.Data.OleDb;

OleDbConnection con = new OleDbConnection ("Provider = Microsoft.Jet.OLEDB.4.0; Data Source = d:\student.mdb;");
OleDbDataAdapter sda = new OleDbDataAdapter ("select * from studentDetails", con);
DataSet ds = new DataSet ();
sda.Fill (ds, "student");
this.DataGrid1.DataSource = ds.Tables ["student"];

// If it is WebForm, you have to add this sentence
//this.DataGrid1.DataBind ();

jy156888

Thank you! The problem has been solved!

savage698

The easiest way, drag a connection control up, there is a wizard