我是个刚学C#的初学者，我写了一个登录界面，现在不知道怎么链接数据库，也不知道用哪一种数据库，不知道是不是可以用Access，如果可以用请各位大神给个实例或教我一下好行。
你可以封装一个SQLHELP的类 代码如下：
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Web;
namespace WebApplication1
{
public class SQLHELP
{
static string config = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;//配置文件
public static int ExecuteNonQuery(string sql, params SqlParameter[] Parameter)//申明一个ExecuteNonQuery方法 params代表部分参数
{
using (SqlConnection conn = new SqlConnection(config))//数据库的连接
{
conn.Open();
using (SqlCommand comm = conn.CreateCommand())
{
comm.CommandText = sql;//sql语句
comm.Parameters.AddRange(Parameter);
return comm.ExecuteNonQuery();//返回申明的ExecuteNonQuery 是返回一条查询记录
}
}
}
public static string ExecuteScalar(string sql, params SqlParameter[] Parameter)//申明一个类型为object ExecuteScalar的方法名
{
using (SqlConnection conn = new SqlConnection(config))//数据库连接
{
conn.Open();
using (SqlCommand comm = conn.CreateCommand())
{
comm.CommandText = sql;
comm.Parameters.AddRange(Parameter);
return comm.ExecuteScalar().ToString();//ExecuteScalar返回的是多条查询记录
}
}
}
public static DataTable ExecuteDataTable(string sql, params SqlParameter[] Parameter)//此方法返回DataSet对象，该对象包含由某一命令返回的结果集
{
using (SqlConnection conn = new SqlConnection(config))
{
conn.Open();
using (SqlCommand comm = conn.CreateCommand())
{
comm.CommandText = sql;
comm.Parameters.AddRange(Parameter);
using (SqlDataAdapter da = new SqlDataAdapter(comm))
{
DataSet dt = new DataSet();
da.Fill(dt);//填充
return dt.Tables[0];
}
}
}
}
}
}
数据库SQL-SERVER就可以了。
下面是我曾经写的一个数据连接的工具类DBUtil
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
namespace AdoNetTemplet
{
///
/// 数据库访问工具类，通常为singleton
///
public class DBUtil
{
private const String CONNSTR = "datasource=.;uid=sa;pwd=sa";
private static DBUtil instance = null;
private static Object lockObj = new Object();
/// <summary>
/// 私有的构造器
/// </summary>
private DBUtil() { }
//得到工具类的实例
public static DBUtil getInstance()
{
if (null == instance)
{
lock (lockObj)//加锁，使得它是线程安全的
{
if (null == instance)
{
instance = new DBUtil();
}
}
}
return instance;
}
//得到一个连接对象
public SqlConnection getConnection()
{
return new SqlConnection(CONNSTR);
}
//得到一个sql操作对象
public SqlCommand getCommand(SqlConnection conn)
{
return conn.CreateCommand();
}
//关闭资源
public void free(SqlConnection conn, SqlCommand command)
{
if (null == command)
{
command.Dispose();
}
if (null == conn)
{
conn.Dispose();
}
}
}
}
//下面是写的增删改查的demo，希望能对你有用
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Data;
namespace AdoNetTemplet
{
///
/// 数据库访问层类
///
class Dao
{
private const String CONNSTR = "Data Source=.;Initial Catalog=student;User ID=sa";
/// <summary>
/// 添加一个用户对象
/// </summary>
/// <param name="user">用户对象</param>
/// <returns>如果添加成功返回true,否则返回false</returns>
public Boolean add(User user)
{
using(SqlConnection conn = new SqlConnection(CONNSTR))
{
conn.Open();
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = @"insert into user (username,password,age,gender)
values(@username,@password,@age,@gender)";
cmd.Parameters.Add(new SqlParameter("@username", user.UserName));
cmd.Parameters.Add(new SqlParameter("@password", user.Password));
cmd.Parameters.Add(new SqlParameter("@age", user.Age));
cmd.Parameters.Add(new SqlParameter("@gender", user.Gender));
return cmd.ExecuteNonQuery()>0;
}
}
}
/// <summary>
/// 通过用户Id删除一条记录
/// </summary>
/// <param name="userId">用户Id</param>
/// <returns>如果删除成功返回true,否则返回false</returns>
public Boolean delete(int userId)
{
using (SqlConnection conn = new SqlConnection(CONNSTR))
{
conn.Open();
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = "delete from user where id=@id";
cmd.Parameters.Add("@id", userId);
return cmd.ExecuteNonQuery() > 0;
}
}
}
/// <summary>
/// 更新一条记录
/// </summary>
/// <param name="user">用户对象</param>
/// <returns>如果更新成功返回true,否则返回false</returns>
public Boolean update(User user)
{
using (SqlConnection conn = new SqlConnection())
{
conn.Open();
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = @"update user set userName=@username,password=@password,
age=@age,gender=@gender ";
cmd.Parameters.Add("@username", user.UserName);
cmd.Parameters.Add("@password", user.Password);
cmd.Parameters.Add("@age", user.Age);
cmd.Parameters.Add("@gender", user.Gender);
return cmd.ExecuteNonQuery() > 0;
}
}
}
/// <summary>
/// 根据Id获取一个User对象
/// </summary>
/// <param name="userId">用户ID</param>
/// <returns>如果存在满足该ID的用户返回该用户对象，否则返回null</returns>
public User loadById(int userId)
{
using (SqlConnection conn = new SqlConnection(CONNSTR))
{
conn.Open();
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = "select * from user where id=@id";
cmd.Parameters.Add(new SqlParameter("@id", userId));
SqlDataReader reader = cmd.ExecuteReader();
User user = null;
if (reader.Read())
{
user = new User();
user.UserName = reader.GetString(reader.GetOrdinal("userName"));
user.Password = reader.GetString(reader.GetOrdinal("password"));
user.Age = reader.GetInt32(reader.GetOrdinal("age"));
user.Gender = reader.GetString(reader.GetOrdinal("gender"));
}
return user;
}
}
}
/// <summary>
/// 获取到所有用户对象
/// </summary>
/// <returns>
/// 如果数据存在用户的记录，将这些记录全部以User对象添加到集合中，并将集合返回；
/// 如果数据库中没有任何记录，将返回null;
/// </returns>
public List<User> getAllUsers()
{
using (SqlConnection conn = new SqlConnection(CONNSTR))
{
conn.Open();
using (SqlCommand cmd = conn.CreateCommand())
{
cmd.CommandText = "select * from user";
SqlDataReader reader = cmd.ExecuteReader();
List<User> users = new List<User>();
User user;
while (reader.Read())
{
user = new User();
user.UserName = reader.GetString(reader.GetOrdinal("userName"));
user.Password = reader.GetString(reader.GetOrdinal("password"));
user.Age = reader.GetInt32(reader.GetOrdinal("age"));
user.Gender = reader.GetString(reader.GetOrdinal("gender"));
users.Add(user);
}
return users;
}
}
}
}
}