数据库增删改查代码，登录和注册

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

namespace data
{
public class cangkudata
{
private string cno;

public string Cno
{
get { return cno; }
set { cno = value; }
}
private string city;

public string City
{
get { return city; }
set { city = value; }
}
private int mianji;

public int Mianji
{
get { return mianji; }
set { mianji = value; }
}
}
}

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

namespace DA
{
public  class cangkuDA
{
SqlConnection coon;
SqlCommand cmd;

public cangkuDA()
{
coon = new SqlConnection("server=.;database=cangku;user=sa;pwd=123");
cmd = coon.CreateCommand();
}
public void Insert(cangkudata data)
{
cmd.CommandText = "insert into cangkubiao values(@cno,@city,@mianji)";
cmd.Parameters.Clear();
cmd.Parameters.Add("@cno",data.Cno);
cmd.Parameters.Add("@city",data.City);
cmd.Parameters.Add("@mianji",data.Mianji.ToString());
coon.Open();
cmd.ExecuteNonQuery();
coon.Close();
}
public void Delete(string cno)
{
cmd.CommandText = "delete from cangkubiao where cno=@cno";
cmd.Parameters.Clear();
cmd.Parameters.Add("@cno",cno);
coon.Open();
cmd.ExecuteNonQuery();
coon.Close();
}
public void Update(cangkudata data)
{
cmd.CommandText = "update cangkubiao set city=@city,mianji=@mianji where cno=@cno";
cmd.Parameters.Clear();
cmd.Parameters.Add("cno",data.Cno);
cmd.Parameters.Add("city",data.City);
cmd.Parameters.Add("mianji",data.Mianji);
coon.Open();
cmd.ExecuteNonQuery();
coon.Close();
}
public List<cangkudata> Select()
{
List<cangkudata> list = new List<cangkudata>();
cmd.CommandText = "select*from cangkubiao";
coon.Open();
SqlDataReader dr = cmd.ExecuteReader();
if (dr.HasRows )
{
while (dr.Read ())
{
cangkudata data = new cangkudata();
data.Cno = dr["cno"].ToString();
data.City = dr["city"].ToString();
data.Mianji =int.Parse ( dr["mianji"].ToString());

list.Add(data);
}
}
cmd.Dispose();
coon.Close();
return list;
}
public List<cangkudata> Select1(string cno,string city,int mianji)
{
List<cangkudata> list = new List<cangkudata>();
cmd.CommandText = "select*from cangkubiao where cno like '%"+cno+"%' and city like '%"+city+"%' and mianji like '%"+mianji+"%'";
coon.Open();
SqlDataReader dr = cmd.ExecuteReader();
if (dr.HasRows)
{
while (dr.Read())
{
cangkudata data = new cangkudata();
data.Cno = dr["cno"].ToString();
data.City = dr["city"].ToString();
data.Mianji =int.Parse ( dr["mianji"].ToString());

list.Add(data);
}
}
cmd.Dispose();
coon.Close();
return list;
}
public cangkudata Select2(string cno)
{
cangkudata data = null;
cmd.CommandText = "select*from cangkubiao where cno=@cno";
cmd.Parameters.Clear();
cmd.Parameters.Add("@cno",cno);
coon.Open();
SqlDataReader dr = cmd.ExecuteReader();
if (dr.HasRows )
{
if (dr.Read ())
{
data = new cangkudata();
data.Cno = dr["cno"].ToString();
data.City = dr["city"].ToString();
data.Mianji =int.Parse ( dr["mianji"].ToString ());
}
}
cmd.Dispose();
coon.Close();
return data;
}
}
}

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 data;
using DA;

namespace 连接仓库
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
//清空
private void button6_Click(object sender, EventArgs e)
{
listView1.Items.Clear();
comboBox1.Text = null;
comboBox2.Text = null;
comboBox3.Text = null;
}
//显示界面
private void Form1_Load(object sender, EventArgs e)
{
List<cangkudata> list = new cangkuDA().Select();
if (list!=null)
{
foreach (cangkudata x in list)
{
comboBox1.Items.Add(x.Cno);
comboBox2.Items.Add(x.City);
comboBox3.Items.Add(x.Mianji);
}
}
}
//显示方法
public void  fangfa(List<cangkudata > list)
{
listView1.Columns.Clear();
listView1.Columns.Add("仓库号");
listView1.Columns.Add("城市");
listView1.Columns.Add("仓库面积");

if (listView1.Items !=null)
{
listView1.Items.Clear();
for (int i = 0; i <list.Count; i++)
{
listView1.Items.Add(list[i].Cno);
listView1.Items[i].SubItems.Add(list[i].City);
listView1.Items[i].SubItems.Add(list[i].Mianji.ToString ());
}

}
}
//查询
private void button1_Click(object sender, EventArgs e)
{
List<cangkudata> list = new cangkuDA().Select();
fangfa(list);
}
//条件查询
private void button5_Click(object sender, EventArgs e)
{
List<cangkudata> list = new cangkuDA().Select1(comboBox1 .Text,comboBox2 .Text ,int.Parse                  (comboBox3 .Text ) );
fangfa(list);
}
//删除
private void button4_Click(object sender, EventArgs e)
{
try
{
if (listView1.SelectedItems.Count > 0)
{
string cno = listView1.SelectedItems[0].Text;
new cangkuDA().Delete(cno);
}

fangfa(new cangkuDA().Select());
}
catch
{
MessageBox.Show("请先删除外键！");
}
}
//点击修改
private void button3_Click(object sender, EventArgs e)
{
if (listView1 .SelectedItems .Count >0)
{
string cno = listView1.SelectedItems[0].Text;
cangkudata data = new cangkuDA().Select2(cno);
comboBox1.Text = data.Cno;
comboBox2.Text = data.City;
comboBox3.Text = data.Mianji.ToString ();
}
cangkudata data1= new cangkudata();
data1.Cno = comboBox1.Text;
data1.City = comboBox2.Text;
data1.Mianji =int.Parse (comboBox3.Text);
new cangkuDA().Update(data1);
fangfa(new cangkuDA ().Select());
}
//添加
private void button2_Click(object sender, EventArgs e)
{

cangkudata data = new cangkudata();
data.Cno = comboBox1.Text;
data.City = comboBox2.Text;
data.Mianji = int.Parse(comboBox3.Text);

new cangkuDA().Insert(data);
fangfa(new cangkuDA().Select());

}
}
}

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 data4;
using DA4;
using 连接仓库.管理员;
using data5;
using DA5;

namespace 连接仓库
{
public partial class zhucejiemian : Form
{
public zhucejiemian()
{
InitializeComponent();
}
//显示界面
private void zhucejiemian_Load(object sender, EventArgs e)
{
sheng();

}
private void sheng()
{
List<dizhidata> list = new dizhiDA().Select();
foreach (dizhidata x in list)
{
comboBox1.Items.Add(x.Sheng);
comboBox1.Text = comboBox1.Items[0].ToString();
}
}
private void shi()
{
List<dizhidata> list = new dizhiDA().Selectsheng(comboBox1.Text);
foreach (dizhidata x in list)
{
comboBox2.Items.Add(x.Shi);
comboBox2.Text = comboBox2.Items[0].ToString();
}
}
private void qu()
{
List<dizhidata> list = new dizhiDA().Selectshi(comboBox2.Text);
foreach (dizhidata x in list)
{
comboBox3.Items.Add(x.Qu);

}
}
//当点击城市的时候
private void button2_Click(object sender, EventArgs e)
{
comboBox2.Items.Clear();
shi();
comboBox2.Text = comboBox2.Items[0].ToString ();

}
//当点击区县的时候
private void button3_Click(object sender, EventArgs e)
{
comboBox3.Items.Clear();
qu();
comboBox3.Text = comboBox3.Items[0].ToString();
}

//当点击注册的时候
private void button1_Click(object sender, EventArgs e)
{
zhucehoutaidata5 data = new zhucehoutaidata5();
data.Nicheng = textBox1.Text;
data.Mima = textBox2.Text;
data.Mima1 = textBox3.Text;
data.Xingming = textBox4.Text;
data.Haoma = textBox5.Text;
data.Phone = textBox6.Text;
data.Youxiang = textBox7.Text;
data.Sheng = comboBox1.Text;
data.Shi = comboBox2.Text;
data.Qu = comboBox3.Text;

new zhucehoutaiDA().Insert(data);

bool a;
try
{
a = true;
string x = textBox6.Text;
for (int i = 0; i < x.Length; i++)
{
string x1 = x.Substring(i, 1);
int x2 = Convert.ToInt32(x1);
}
}
catch
{
a = false;
}

if (textBox1.Text.Length==0)
{
MessageBox.Show("昵称不能为空");
}
else if (textBox2 .Text.Length==0)
{
MessageBox.Show("密码不能为空");
}
else if (textBox3.Text!=textBox2.Text )
{
MessageBox.Show("两次输入密码不一致");
}
else if (textBox4.Text.Length ==0)//怎样判断是否输入的汉字？？
{

MessageBox.Show("姓名不能为空");

}
else if (textBox5.Text.Trim().Length==0)
{
MessageBox.Show("请输入您的身份证号码");
}
else if (textBox6.Text.Trim().Length == 0 || textBox6.Text.Trim().Length < 11 || a==false)
{
MessageBox.Show("请输入正确手机号");
}

else if (!textBox7.Text.Contains("@") && !textBox7.Text.Contains(".com"))
{
MessageBox.Show("请输入一个正确的邮箱格式");
}
else
{
MessageBox.Show("恭喜你注册成功！");
denglu f = new denglu();
this.Visible = false;
this.Owner = f;
f.Show();
}
}

}
}

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 data1;
using DA1;
using data5;
using DA5;

namespace 连接仓库.管理员
{
public partial class denglu : Form
{
public denglu()
{
InitializeComponent();
}

private void denglu_Load(object sender, EventArgs e)
{

List<zhucehoutaidata5> list = new zhucehoutaiDA().Select1();
if (list!=null)
{
foreach (zhucehoutaidata5 x in list)
{
comboBox1.Items.Add(x.Nicheng);
}
}
}
//点击登录按钮
private void button1_Click(object sender, EventArgs e)
{
string nicheng=comboBox1.Text;
string mima=textBox1 .Text ;
List<zhucehoutaidata5> list = new zhucehoutaiDA().Select(nicheng,mima);
if (list != null)
{
MessageBox.Show("登录成功");
cangkuguanli f = new cangkuguanli();
this.Owner = f;
f.WindowState = FormWindowState.Maximized; //这句话什么意思
this.Visible = false;
f.Show();
}
else
{
MessageBox.Show("登录失败");
}

/*if (list != null)
{
foreach (zhigongdata x in list)
{
comboBox1.Items.Add(x.Cno);
comboBox2.Items.Add(x.Zno);
}

}
if (comboBox1.Text == comboBox1.Items[0].ToString() && comboBox2.Text == comboBox2.Items[1].ToString())
{
MessageBox.Show("登录成功");
cangkuguanli f = new cangkuguanli();
this.Owner = f;
f.WindowState = FormWindowState.Maximized; //这句话什么意思
this.Visible = false;
f.Show();
}
else
{
MessageBox.Show("登录失败");
}*/
}
//当点击注册的时候
private void button2_Click(object sender, EventArgs e)
{
zhucejiemian f = new zhucejiemian();

this.Visible = false;
this.Owner = f;
f.Show();
}
}
}