简单登录设计增删改查

 获得数据,验证用户输入

            //获得数据,验证用户输入
            string yz1 = textBox1.Text.Trim();
            string yz2 = textBox2.Text.Trim();
            if (yz1==""||yz2=="")
            {

                MessageBox.Show("请正确输入用户名或密码");
                return;
            }
            if (!ValidatorHelper.IsLetter(yz1))
            {
                MessageBox.Show("用户名必须是英文字母");
                return;
            }

将获得的数据从数据库中查询比较

            try
            {
                Class2 cs = new Class2();
                bool it = cs.tof(textBox1.Text.Trim(),textBox2.Text.Trim());
                if (it)
                {
                    MessageBox.Show("登录成功");
                    Main main = new Main();
                    main.Show();
                }
                else
                {
                    MessageBox.Show("登录失败");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message );
            
            }

这里的都是sql语句，对数据库的连接

public  class Class2
    {
       public string cc = "Data Source=.;Initial Catalog=test;User ID=sa;Pwd=123";
        public bool tof(string UserName,string UserPassword)
        {

            string sql = string.Format("SELECT COUNT(*) FROM demoUsers WHERE UserName=@UserName AND UserPassword = @UserPassword");
            Class1 q = new Class1(cc);
            ArrayList paramlist = new ArrayList();
            paramlist.Add(q.CreateParameter("@UserName", UserName, DbType.String, 50));//参数化sql语句
            paramlist.Add(q.CreateParameter("@UserPassword", UserPassword, DbType.String, 50));//参数化sql语句
            IDataParameter[] param = (IDataParameter[])paramlist.ToArray(typeof(IDataParameter));
            object dt = q.ExecuteScalar(sql, param);
            int it = Convert.ToInt32(dt);
            return  it>0;
        }

       //读出数据,并列出在main界面
        public DataTable li(int UserId)
        {
            string sql = string.Format("SELECT * FROM demoUsers WHERE UserId=@UserId");
            Class1 q = new Class1(cc);
            ArrayList paramlist = new ArrayList();
            paramlist.Add(q.CreateParameter("@UserId", UserId, DbType.Int32 , 4));
            IDataParameter[] param = (IDataParameter[])paramlist.ToArray(typeof(IDataParameter));
            return q.testDataTable(sql, param);
        }

    }

对数据库的操作，复制过来的，还没自己写出来过，其中用了dataSet

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


namespace _111
{
    public class Class1
    {
        private string connstr="" ;
        public Class1(string abc)
        { connstr = abc; }
        #region Execute
        /// <summary>
        /// 执行sql语句
        /// </summary>
        /// <param name="sql">sql语句</param>
        public void Execute(string sql)
        {
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                using (SqlCommand cmd = new SqlCommand(sql, conn))
                {
                    try
                    {
                        conn.Open();
                        int v = cmd.ExecuteNonQuery();
                    }
                    catch (Exception e)
                    {
                        throw new Exception(e.Message + sql, e);
                    }
                }
            }
        }
        #endregion

        #region ExecuteNonQuery
        /// <summary>
        /// 执行sql语句返回命令影响的行数
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <param name="param">参数组</param>
        /// <returns>返回命令影响的行数</returns>
        public int ExecuteNonQuery(string sql, IDataParameter[] param)
        {
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                using (SqlCommand cmd = new SqlCommand(sql, conn))
                {
                    try
                    {
                        conn.Open();
                        AttachParameters(cmd, param);
                        int v = cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();
                        return v;
                    }
                    catch (Exception e)
                    {
                        throw new Exception(e.Message + sql, e);
                    }
                }
            }
        }
        #endregion

        #region ExecuteScalar
        /// <summary>
        /// 执行sql语句
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <param name="param">参数组</param>
        /// <returns>返回第一行的第一列</returns>
        public object ExecuteScalar(string sql, IDataParameter[] param)
        {
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                using (SqlCommand cmd = new SqlCommand(sql, conn))
                {
                    try
                    {
                        conn.Open();
                        AttachParameters(cmd, param);
                        object v = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        return v;
                    }
                    catch (Exception e)
                    {
                        throw new Exception(e.Message + sql, e);
                    }
                }
            }
        }
        #endregion

        #region ExecuteIdentity
        /// <summary>
        /// 执行sql语句 并返回自增字段值
        /// </summary>
        /// <param name="sql">SQL语句</param>
        /// <param name="param">参数组</param>
        /// <returns>自增列值</returns>
        public  object ExecuteIdentity(string sql, IDataParameter[] param)
        {
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    try
                    {
                        conn.Open();
                       // SqlTransaction trans = conn.BeginTransaction();
                        //PrepareCommand(cmd, conn, trans, CommandType.Text, sql, param);
                       // cmd.ExecuteScalar();
                       // cmd.Parameters.Clear();
                        cmd.CommandText = sql +";select @@IDENTITY";//SELECT SCOPE_IDENTITY()
                      //  trans.Commit();
                        object v = cmd.ExecuteScalar();
                        cmd.Parameters.Clear();
                        return v;
                    }
                    catch (Exception e)
                    {
                        throw new Exception(e.Message + sql, e);
                    }
                }
            }
        }
        #endregion

        #region ExecuteReader
        /// <summary>
        /// 执行sql语句
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="param">参数组</param>
        /// <returns>返回DataReader对象</returns>
        public  IDataReader ExecuteReader(string sql, IDataParameter[] param)
        {
            SqlConnection conn = new SqlConnection(connstr);
            using (SqlCommand cmd = new SqlCommand(sql, conn))
            {
                try
                {
                    conn.Open();
                    AttachParameters(cmd, param);
                    IDataReader r = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                    cmd.Parameters.Clear();
                    return r;
                }
                catch (Exception e)
                {
                    throw new Exception(e.Message + sql, e);
                }
            }
        }
        #endregion

        #region ExecuteDataSet
        /// <summary>
        /// 执行sql语句
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="param">参数组</param>
        /// <returns>返回DataSet对象</returns>
        public  DataSet ExecuteDataSet(string sql, IDataParameter[] param)
        {
            using (SqlConnection conn = new SqlConnection(connstr))
            {
                using (SqlCommand cmd = new SqlCommand(sql, conn))
                {
                    conn.Open();
                    AttachParameters(cmd, param);
                    using (SqlDataAdapter da = new SqlDataAdapter())
                    {
                        da.SelectCommand = cmd;
                        DataSet ds = new DataSet();
                        try
                        {
                            ds.EnforceConstraints = false;
                            da.Fill(ds);
                            ds.EnforceConstraints = true;
                            //当系统从数据库中获取数据并填充到datatable中时，或自动根据其约束来验证每一行(比如主键、唯约束等等)，这样是以牺牲系统性能为代价的。
                            //既然是从关系数据库中提取出来的数据，那么对数据约束的检查应该丢给它来做。在填充数据集前可以利用dataset的EnforceConstraints属性来开关数据约束检查。
                        }
                        catch (Exception e)
                        {
                            throw new Exception(e.Message + sql, e);
                        }
                        cmd.Parameters.Clear();
                        return ds;
                    }
                }

            }
        }
        #endregion
        public DataTable testDataTable(string sql, IDataParameter[] param)
        {
            DataSet set = ExecuteDataSet(sql, param);
            return set.Tables[0];
        }
        #region 为DbCommand对象附加DataParameter参数
        /// <summary>
        /// 为DbCommand对象附加DataParameter参数
        /// </summary>
        /// <param name="cmd">DbCommand对象</param>
        /// <param name="parameters">DataParameter参数数组</param>
        public  void AttachParameters(IDbCommand cmd, IDataParameter[] parameters)
        {
            if (parameters == null) return;
            foreach (IDataParameter p in parameters)
            {
                if (p != null)
                {
                    if (p.Value == null)
                    {
                        p.Value = DBNull.Value;
                    }
                    cmd.Parameters.Add(p);
                }
            }
        }
        #endregion


        #region Parameter
        /// <summary>
        /// 根据占位符和值创建参数
        /// </summary>
        /// <param name="name">占位符名称</param>
        /// <param name="value">占位符的值</param>
        /// <param name="type">数据类型</param>
        /// <param name="size">数据最大长度</param>
        /// <returns></returns>
        public    IDataParameter CreateParameter(string name, object value, DbType type, int size)
        {
            SqlParameter p = new SqlParameter(name, type);
            p.Value = value;
            if (size > 0) p.Size = size;
            return p;
        }
        #endregion


    }
}

主界面将数据显示出来，目前是支持根据ID查询

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
using _111;

namespace ManagerSystem
{
    public partial class Main : Form
    {
        public Main()
        {
            InitializeComponent();
        }

        private void button4_Click(object sender, EventArgs e)
        {
            int id;
            Class2 ds = new Class2();
            if (true)
            {
                id = Convert.ToInt32(textBox1.Text.Trim());
            }
                DataTable dt = ds.li(id);//将Id传进去得到一个数据表
                if (dt.Rows.Count>0)
                {
                    this.textBox1.Text = dt.Rows[0]["UserId"].ToString();//显示ID
                    this.textBox2.Text = dt.Rows[0]["UserName"].ToString();//显示用户名
                    this.textBox4.Text = Convert.ToBoolean(dt.Rows[0]["UserSex"])?"男":"女";//显示性别
                    this.textBox5.Text = dt.Rows[0]["UserPhone"].ToString();//手机号
                    this.textBox6.Text = dt.Rows[0]["UserAge"].ToString();//年龄
                }
                else
                {
                    MessageBox.Show("此ID不存在!");
                }
            


         
           // this.textBox3.Text = Convert.ToString(reader["UserSex"]);//显示性别
        }

        private void Main_Load(object sender, EventArgs e)
        {

        }
    }
}

登录成功后，显示主窗体，并且登录框消失

         static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Login login = new Login();
            if (login.ShowDialog()==DialogResult.OK)
            {
                Application.Run(new Main());
            }
            
            
        }



//Login。cs
 MessageBox.Show("登录成功");
                    this.DialogResult = DialogResult.OK;

 前面的代码没有一个中心思路下来,自己菜鸟也模模糊糊有点感觉,想着记录下来,以后回头学学,看看

//UpDate数据库  这里是UI层

 //更改数据
        private void button3_Click(object sender, EventArgs e)
        {
            //获得用户输入值
            int userId = TypeHelper.ToInt(textBox1.Text.Trim());
            string userName = textBox2.Text.Trim();
            string userPwd = textBox3.Text.Trim();
            bool userSex;
            string userPhone = textBox5.Text.Trim();
            int userAge = TypeHelper.ToInt(textBox6.Text.Trim());

            if (!ValidatorHelper.IsLetter(userName) && userName != "")
            {
                MessageBox.Show("用户名必须是非空英文字母");
                return;
            }
            if (userPwd == "")
            {
                MessageBox.Show("密码不能为空");
                return;
            }

            if (userPhone=="")
            {
                MessageBox.Show("输入正确的联系方式");
                return;
            }

            if (userAge > 60 || userAge < 18)
            {
                MessageBox.Show("年龄在18与60之间");
                return;
            }
            if (radioButton1.Checked)
            {
                userSex = true;
            }
            else if (radioButton2.Checked)
            {
                userSex = false;
            }

            else
            {
                MessageBox.Show("输入性别");
                return;
            }
            try
            {
                int phone = Convert.ToInt32(textBox5.Text.Trim());
                int age = Convert.ToInt32(textBox6.Text.Trim());


                UserInfo userinfo = new UserInfo();//实例化Mod
                //将指传给实体层
                userinfo.UserName = userName;
                userinfo.UserPassword = userPwd;
                userinfo.UserSex = userSex;
                userinfo.UserPhone = userPhone;
                userinfo.UserAge = userAge;
                userinfo.UserId = userId;
                SqlHelper ss = new SqlHelper();
                bool it = ss.update(userinfo);//这里userinfo引用的是实体类,而实体类是桥梁架通了数据层
                if (it)
                {
                    MessageBox.Show("修改成功");
                }
                else
                {
                    MessageBox.Show("修改失败");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

//sqlhelper  dal层

 //更改数据
        public bool update(UserInfo userinfo)
        {
            string sql = string.Format(" UPDATE demoUsers SET UserName=@UserName,UserPassword=@UserPassword,UserSex=@UserSex,UserPhone=@UserPhone,UserAge=@UserAge WHERE UserId=@UserId");
            Class1 q = new Class1(cc);
            ArrayList paramlist = new ArrayList();
            paramlist.Add(q.CreateParameter("@UserName", userinfo.UserName, DbType.String, 50));
            paramlist.Add(q.CreateParameter("@UserPassword", userinfo.UserPassword, DbType.String, 50));
            paramlist.Add(q.CreateParameter("@UserSex", userinfo.UserSex, DbType.Boolean, 1));
            paramlist.Add(q.CreateParameter("@UserPhone", userinfo.UserPhone, DbType.Int32, 4));
            paramlist.Add(q.CreateParameter("@UserAge", userinfo.UserAge, DbType.Int32, 4));
            paramlist.Add(q.CreateParameter("@UserId", userinfo.UserId, DbType.Int32, 4));
            IDataParameter[] param = (IDataParameter[])paramlist.ToArray(typeof(IDataParameter));
            object dt = q.ExecuteNonQuery(sql, param);
            int it = Convert.ToInt32(dt);
            return it > 0;
            
        }

//MOD  实体层

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace _111
{
    public class UserInfo
    {
        private string userName;
        private string userPassword;
        public string UserName
        {
            get { return userName; }
            set { userName = value; }
        }

        public string UserPassword
        {
            get { return userPassword; }
            set { userPassword = value; }
        }
        private bool userSex;
        public bool UserSex
        {
            get { return userSex; }
            set { userSex = value; }
        }
        private string userPhone;
        public string UserPhone
        {
            get { return userPhone; }
            set { userPhone = value; }
        }
        private int userAge;
        public int UserAge
        {
            get { return userAge; }
            set { userAge = value; }
        }
        private int userId;
        public int UserId
        {
            get { return userId; }
            set { userId = value; }
        }
    }
}