WinForm连接数据库增删改查

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

namespace LeikuObject
{
public class TelObject
{
private int _Code;

public int Code
{
get { return _Code; }
set { _Code = value; }
}
private string _Name;

public string Name
{
get { return _Name; }
set { _Name = value; }
}
private string _Sex;

public string Sex
{
get { return _Sex; }
set { _Sex = value; }
}
private string _Phone;

public string Phone
{
get { return _Phone; }
set { _Phone = value; }
}
}
}

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

namespace LeikuFunction
{
public class Function
{
SqlConnection conn;
SqlCommand cmd;
string sr = "server=.;database=lianxi;uid=sa;pwd=123";
public Function()
{
conn = new SqlConnection(sr);//通过构造函数连接数据库
cmd = conn.CreateCommand();//创建一个与SqlConnection(表示一个连接数据库的链接)和SqlCommand(表示要对数据库进行操作的SQL语句)相关联的的对象
}

/// <summary>
/// 查询
/// </summary>
/// <returns></returns>
public List<TelObject> select()
{
List<TelObject> list = null;
cmd.CommandText = "select * from tel";//存储SQL语句
conn.Open();//打开数据库连接
SqlDataReader dr = cmd.ExecuteReader();//SqlDataReader 提供一种从数据库读取行的只进流方式 ExecuteReader:将 CommandText 发送到 Connection 并生成一个 SqlDataReader

if (dr.HasRows)//判断dr中有没有数据
{
list = new List<TelObject>();
while (dr.Read())//dr中读取到的行 返回true 读取的行会先存在dr中
{
TelObject t = new TelObject();//这句如果放在while外面，就会只造了一个TelObject对象 只会带着一个对象的值存入list集合中
t.Code=int.Parse(dr["code"].ToString());
t.Name = dr["name"].ToString();
t.Sex = dr["sex"].ToString();
t.Phone = dr["iph"].ToString();
list.Add(t);
}
}
cmd.Dispose();//销毁cmd
conn.Close();//关闭数据库连接
return list;
}

/// <summary>
/// 删除
/// </summary>
/// <param name="code"></param>
public void delete(int code)
{
cmd.CommandText = "delete from tel where code=@code";//使用@占位符 可以避免注入攻击
cmd.Parameters.Clear();
cmd.Parameters.Add("@code",code);//给占位符赋值
conn.Open();
cmd.ExecuteNonQuery();//执行SQL语句，并返回受影响的行
cmd.Dispose();
conn.Close();
}

/// <summary>
/// 单独查询
/// </summary>
/// <param name="code"></param>
/// <returns></returns>
public TelObject select(int code)
{
TelObject t = null;
cmd.CommandText = "select *from tel where code=@code";
cmd.Parameters.Clear();
cmd.Parameters.Add("@code", code);
conn.Open();
SqlDataReader dr = cmd.ExecuteReader();
if (dr.HasRows)
{
t = new TelObject();
if (dr.Read())//如果不加这一步，直接赋值，会报错？
{
t.Code = int.Parse(dr["code"].ToString());
t.Name = dr["name"].ToString();
t.Sex = dr["sex"].ToString();
t.Phone = dr["iph"].ToString();
}
}
cmd.Dispose();
conn.Close();
return t;
}

/// <summary>
/// 增加
/// </summary>
/// <param name="t"></param>
public void insert(TelObject t)
{
cmd.CommandText = "insert into tel values(@code,@name,@sex,@iph)";
cmd.Parameters.Clear();
cmd.Parameters.Add("@code", t.Code);
cmd.Parameters.Add("@name", t.Name);
cmd.Parameters.Add("@sex", t.Sex);
cmd.Parameters.Add("@iph", t.Phone);
conn.Open();
cmd.ExecuteNonQuery();//执行SQL语句，并返回受影响的行
cmd.Dispose();
conn.Close();
}

/// <summary>
/// 修改
/// </summary>
/// <param name="t"></param>
public void update(TelObject t)
{
cmd.CommandText = "update tel set name=@name,sex=@sex,iph=@iph where code=@code";
cmd.Parameters.Clear();
cmd.Parameters.Add("@code", t.Code);
cmd.Parameters.Add("@name", t.Name);
cmd.Parameters.Add("@sex", t.Sex);
cmd.Parameters.Add("@iph", t.Phone);
conn.Open();
cmd.ExecuteNonQuery();//执行SQL语句，并返回受影响的行
cmd.Dispose();
conn.Close();
}

/// <summary>
/// 模糊查询
/// </summary>
/// <param name="name"></param>
/// <param name="sex"></param>
/// <returns></returns>
public List<TelObject> select(string name,string sex)
{
List<TelObject> list = null;
cmd.CommandText = "select * from tel where name like '%"+name+"%' and sex like '%"+sex+"%'";
//这个地方不能用占位符，不解，暂时用拼接字符串吧
conn.Open();
SqlDataReader dr = cmd.ExecuteReader();//SqlDataReader 提供一种从数据库读取行的只进流方式 ExecuteReader:将 CommandText 发送到 Connection 并生成一个 SqlDataReader

if (dr.HasRows)//判断dr中有没有数据
{
list = new List<TelObject>();
while (dr.Read())//dr中读取到的行 返回true 读取的行会先存在dr中
{
TelObject t = new TelObject();//这句如果放在while外面，就会只造了一个TelObject对象 只会带着一个对象的值存入list集合中
t.Code = int.Parse(dr["code"].ToString());
t.Name = dr["name"].ToString();
t.Sex = dr["sex"].ToString();
t.Phone = dr["iph"].ToString();
list.Add(t);
}
}
cmd.Dispose();//销毁cmd
conn.Close();//关闭数据库连接
return list;
}
}
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using LeikuObject;
using LeikuFunction;

namespace WindowsFormsApplication3
{
public partial class Form1 : Form//主窗体
{
public Form1()
{
InitializeComponent();
}

public static int time = 0;//定义静态成员
public void chushiselect(List<TelObject> list)//显示查询结果的函数
{
listView1.Columns.Clear();//清空列名，为了防止连续重复调用函数，重复插入列名
listView1.Columns.Add("编号");//添加列名，第一列索引是0 Columns[0] 第二项Columns[1]
listView1.Columns.Add("姓名");
listView1.Columns.Add("性别");
listView1.Columns.Add("电话");
listView1.Items.Clear();//清空行，为了防止连续重复调用函数，重复插入行
//TelObject t = new TelObject();
if (list!=null)
{
for (int i = 0; i < list.Count; i++)
{
listView1.Items.Add(list[i].Code.ToString());//添加行，行的第一列数据
//第一行添加第一列数据时不能这么写listView1.Items[i].SubItems.Add(list[i].Code.ToString())
//添加之前第一列是空的 Items[i].SubItems 空集合里索引0里的SubItems报错 因为index为null
listView1.Items[i].SubItems.Add(list[i].Name);//这一行的，第二列数据，也就是Items这个集合里索引是0的数据
listView1.Items[i].SubItems.Add(list[i].Sex);
listView1.Items[i].SubItems.Add(list[i].Phone);
}
}
}
private void btselect_Click(object sender, EventArgs e)//查询按钮
{
time = 1;
}

private void btdelete_Click(object sender, EventArgs e)//删除按钮
{
//MessageBox.Show(listView1.Items[0].SubItems[1].Text); 可以获取到这一行的第二列数据
//MessageBox.Show(listView1.SelectedItems[0].SubItems[1].Text); 可以获取到选中行的第二列数据
if (listView1.SelectedItems.Count>0)//判读是否选中了一行
{
int code = int.Parse(listView1.SelectedItems[0].Text);//获取选中行的第一列数据 也可以写成listView1.SelectedItems[0].SubItems[0].Text
new Function().delete(code);
time = 1;
}

}

private void btinsert_Click(object sender, EventArgs e)//增加按钮
{
Form2 f = new Form2();
f.Show();
}

private void timer1_Tick(object sender, EventArgs e)//时钟组件，一直在后台等待，当time值有变化，就执行操作
{
if (time==0)
{

}
else if (time==1)
{
List<TelObject> list = new Function().select();
chushiselect(list);
}
time = 0;
}

private void btupdate_Click(object sender, EventArgs e)//修改按钮
{
if (listView1.SelectedItems.Count > 0)
{
int code = int.Parse(listView1.SelectedItems[0].Text);
Form3 f = new Form3(code);//通过构造函数传值，把code传给Form3
f.Show();
}
}

private void btpreselect_Click(object sender, EventArgs e)//条件按钮
{
if (txtmainname.Text.Length>0||txtmainsex.Text.Length>0)
{
string name = txtmainname.Text;
string sex = txtmainsex.Text;
List<TelObject> list = new Function().select(name, sex);
chushiselect(list);
}
}
}
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using LeikuFunction;
using LeikuObject;

namespace WindowsFormsApplication3
{
public partial class Form2 : Form//增加对话框
{
public Form2()
{
InitializeComponent();
}

private void btzengjia_Click(object sender, EventArgs e)
{
//判读文本框里是不是有内容
if (txtcode.Text.Length>0&&txtname.Text.Length>0&&txtsex.Text.Length>0&&txtphone.Text.Length>0)
{
TelObject t = new TelObject();
t.Code = int.Parse(txtcode.Text);
t.Name = txtname.Text;
t.Sex = txtsex.Text;
t.Phone = txtphone.Text;
new Function().insert(t);
Close();//增加完信息关闭增加对话框
Form1.time = 1;//调用Form1中的静态成员，修改time值，为了重新查询数据库，把增加的信息显示出来
}
else
{
MessageBox.Show("信息有误");
}
}
}
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using LeikuObject;
using LeikuFunction;

namespace WindowsFormsApplication3
{
public partial class Form3 : Form
{
private int Code;
public Form3(int code)
{
InitializeComponent();
Code = code;
}

private void btxiugai_Click(object sender, EventArgs e)//修改按钮
{
//判读修改后的文本中是否有内容
if (txtxname.Text.Length>0&&txtxsex.Text.Length>0&&txtxphone.Text.Length>0)
{
TelObject t = new TelObject();
t.Code = int.Parse(txtxcode.Text);
t.Name = txtxname.Text;
t.Sex = txtxsex.Text;
t.Phone = txtxphone.Text;
new Function().update(t);
Close();
Form1.time = 1;
}
}

private void Form3_Load(object sender, EventArgs e)//Form3窗体打开时就会显示的值
{
TelObject t = new Function().select(Code);
txtxcode.Text = t.Code.ToString();
txtxname.Text = t.Name;
txtxsex.Text = t.Sex;
txtxphone.Text = t.Phone;
}
}
}