contactdb.cs

一个简短的通信程序

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;

namespace Contact
{
    class ContactDB
    {
        string connStr = "Data Source = (local);Initial Catalog = contact;user id = sa;password = 1234";
		//string sql;
		//SqlCommand cmd;

        public ContactDB()
		{
			//
			// TODO: 在此处添加构造函数逻辑
			//
		}

		/// <summary>
		/// 获得所有联系人信息
		/// </summary>
		/// <returns>所有联系人信息</returns>
		public SqlDataReader getReader()
		{
			string sql = "select Fid,Fname,Fphone,Faddress from friend";
			SqlConnection conn = new SqlConnection(connStr);
			conn.Open();
			SqlCommand cmd = new SqlCommand(sql,conn);
			SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);
			return reader;
		}

		/// <summary>
		/// 添加新联系人
		/// </summary>
		/// <param name="_name">姓名</param>
		/// <param name="_phone">电话</param>
		/// <param name="_address">地址</param>
		public void addInfo(string _name,string _phone,string _address)
		{
			//可以使用Command Parameter来构造sql语句以获得更好的效率和更高的安全性
			string sql = "insert into friend (Fname,Fphone,Faddress) values ('";
			sql += _name + "','" + _phone + "','" + _address + "')";
			SqlConnection conn = new SqlConnection(connStr);
			SqlCommand cmd = new SqlCommand(sql,conn);
			conn.Open();
			cmd.ExecuteNonQuery();
			conn.Close();
		}

		/// <summary>
		/// 修改联系人信息
		/// </summary>
		/// <param name="_id">需要修改的联系人的id</param>
		/// <param name="_name"></param>
		/// <param name="_phone"></param>
		/// <param name="_address"></param>
		public void changeInfo(int _id,string _name,string _phone,string _address)
		{
			string sql = "update friend set Fname = '" + _name + "',Fphone = '" + _phone + "',Faddress = '" + _address + "'";
            sql += " where Fid = " + _id;
			SqlConnection conn = new SqlConnection(connStr);
			SqlCommand cmd = new SqlCommand(sql,conn);
			conn.Open();
			cmd.ExecuteNonQuery();
			conn.Close();
		}

		/// <summary>
		/// 删除指定fid的联系人信息
		/// </summary>
		/// <param name="infoID"></param>
		public void deleteInfo(int infoID)
		{
			string sql = "delete friend where Fid = " + infoID;
			SqlConnection conn = new SqlConnection(connStr);
			conn.Open();
			SqlCommand cmd = new SqlCommand(sql,conn);
			cmd.ExecuteNonQuery();
			conn.Close();
		}
    }
}