DOC《《》课程设计报告》

业务逻辑层是对系统业务实体的封装,完成系统业务功能;

数据访问层直接与数据库打交道,为业务逻辑层提供底层的数据库操作. 5.1 Database类主要是与数据库连接,提供数据库操作功能,代码如下: namespace MyElectCourse.DAL { public class Database { protected string connectionString;

protected SqlConnection connection = null;

public Database() { connectionString = ConfigurationManager.ConnectionStrings[ ConnectionString ].ConnectionString.ToString();

} ~Database() { if (connection != null) { connection = null;

} } protected void Open() { if (connection == null) { connection = new SqlConnection(connectionString);

} if (connection.State.Equals(ConnectionState.Closed)) { connection.Open();

} } protected void Close() { if (connection != null) { connection.Close();

} } public int ExecuteSQL(string sqlstr) { int count = -1;

this.Open();

SqlCommand cmd = new SqlCommand(sqlstr, connection);

count = cmd.ExecuteNonQuery();

this.Close();

return count;

} public DataSet GetDataSet(string sqlstr) { this.Open();

DataSet ds = new DataSet();

SqlDataAdapter adapter = new SqlDataAdapter(sqlstr,connection);

adapter.Fill(ds);

this.Close();

return ds;

} public DataTable GetDataTable(string sqlstr) { DataSet ds = this.GetDataSet(sqlstr);

DataTable dt = new DataTable();

if (ds.Tables.Count >

0) { dt = ds.Tables[0];

} return dt;

} public SqlDataReader GetDataReader(string sqlstr) { this.Open();

SqlCommand cmd = new SqlCommand(sqlstr, connection);

SqlDataReader sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);

//this.Close();

return sdr;

} } } 5.2 UserBase类是所有系统角色用户的基类,完成用户登录验证与修改密码的功能,代码如下: namespace MyElectCourse.BLL { public class UserBase { private string userID;

public string UserID { get { return userID;

} set { userID = value;

} } private string userPSW;

public string UserPSW { get { return userPSW;

} set { userPSW = value;

} } public string loginCheck(string uid, string upwd, string urole) { String selectStr = String.Empty;

switch (urole) { case

0 身份为教师时 selectStr = Select * from Teacher where teaID = '

+ uid + '

;

break;

case

1 身份为学生时 selectStr = Select * from Student where stuID = '

+ uid + '

;

break;

case

2 身份为管理员时 selectStr = Select * from Users where adminName = '

+ uid + '

;

break;

default: return null;

} Database db = new Database();

DataTable dt = db.GetDataTable(selectStr);

if (dt.Rows.Count >

0)如果该用户存在 { if (dt.Rows[0][1].ToString().Equals(upwd)) //密码正确 { switch (urole) { case

0 身份为教师时 return

0 ;

case

1 身份为学生时 return

1 ;

case

2 身份为管理员时 return

2 ;

default: return null;

} } else //密码错误,给出提示信息! { return -1 ;

} } else //用户不存在或用户名输入错误 { return -2 ;

} } public string modifyPWD(String urole, String uid, String oldPwd, String newPwd) { String updateStr = String.Empty;

switch (urole) { case

0 身份为教师时 updateStr = update Teacher set teaPwd='

+ newPwd + '

where teaID='

+ uid + '

;

break;

case

1 身份为学生时 updateStr = update Student set stuPwd='

+ newPwd + '

where stuID='

+ uid + '

;

break;

case

2 身份为管理员时 updateStr = update Users set adminPwd='