初始数据库
winform设计图
以面向对象的思想，先封装两个类：userDate类存属性，userDA类存方法
userDate类：
public class userDate
{ private int _code;public int Code //封装类
{ get { return _code; } set { _code = value; } } private string _uname;public string Uname
{ get { return _uname; } set { _uname = value; } } private string _upass;public string Upass
{ get { return _upass; } set { _upass = value; } } }userDA类：
class userDA
{ private SqlConnection _Conn; private SqlCommand _Cmd;public userDA()
{ _Conn = new SqlConnection("server=.;database=data1220;user=sa;pwd=sa"); } //添加 public void Insert(userDate data) { } //修改 public void Update(userDate data) { } //删除 public void Delete(int code) { } //查询全部 public List<userDate> Select2() { } //按用户名查询 public List<userDate> Select2(string uname) { } }一、增加：
核心代码：
点击添加时：
private void button1_Click(object sender, EventArgs e)
{ userDate data = new userDate();data.Uname = textBox2.Text;
data.Upass = textBox1.Text;new userDA().Insert(data);
}userDA类中：Insert方法
public void Insert(userDate data)
{ _Conn.Open(); _Cmd = _Conn.CreateCommand(); _Cmd.CommandText = "insert into table1 VALUES (@uname, @upass)";_Cmd.Parameters.Clear();
_Cmd.Parameters.Add("@uname",data.Uname); _Cmd.Parameters.Add("@upass",data.Upass); _Cmd.ExecuteNonQuery(); _Conn.Close(); }1. 点增加 2.查询一下，添加上了
3.数据库里有了
二、查询：
核心代码：
点击查询时：
private void select2_Click(object sender, EventArgs e)
{ List<userDate> list= new userDA().Select2(textBox1.Text); Binding(list); }//封装数据函数
private void Binding(List<userDate> list)
{ listView1.Columns.Clear();listView1.Columns.Add("编号");
listView1.Columns.Add("用户名"); listView1.Columns.Add("密码");listView1.Items.Clear();
foreach (userDate date in list)
{ ListViewItem lt = new ListViewItem(); lt.Text = date.Code.ToString(); lt.SubItems.Add(date.Uname); lt.SubItems.Add(date.Upass);listView1.Items.Add(lt);
} }userDA类中：两个查询函数（重载）
//查询全部
public List<userDate> Select2() { List<userDate> list=new List<userDate>();_Conn.Open();
_Cmd = _Conn.CreateCommand(); _Cmd.CommandText = "select*from table1";SqlDataReader dr = _Cmd.ExecuteReader();
while (dr.Read())
{ userDate data = new userDate(); data.Code = int.Parse(dr["code"].ToString()); data.Uname = dr["uname"].ToString(); data.Upass = dr["upass"].ToString();list.Add(data);
}return list;
} //按用户名查询（条件查询） public List<userDate> Select2(string uname) { List<userDate> list = new List<userDate>();_Conn.Open();
_Cmd = _Conn.CreateCommand(); _Cmd.CommandText = "select * from table1 where uname like '%"+uname+"%'";SqlDataReader dr = _Cmd.ExecuteReader();
while (dr.Read())
{ userDate data = new userDate(); data.Code = int.Parse(dr["code"].ToString()); data.Uname = dr["uname"].ToString(); data.Upass = dr["upass"].ToString();list.Add(data);
}return list;
}1.全部显示： 2.按用户名模糊查询
三、修改
核心代码：
点击时：
private void button1_Click(object sender, EventArgs e)
{ userDate data = new userDate();data.Code = int.Parse(textBox3.Text);
data.Uname = textBox2.Text; data.Upass = textBox1.Text;new userDA().Update(data);
}userDA类中：
public void Update(userDate data)
{ _Conn.Open(); _Cmd = _Conn.CreateCommand(); _Cmd.CommandText = "update table1 set uname='"+data.Uname+"',upass='"+data.Upass+"' where code="+data.Code;_Cmd.ExecuteNonQuery();
_Conn.Close(); }1.点击修改 2.查询后改变了 3。数据库也变了
四、删除
核心代码：
点击时：
private void delete1_Click(object sender, EventArgs e)
{ if (listView1.SelectedItems.Count > 0) // SelectedItems选中项 { int code = int.Parse(listView1.SelectedItems[0].Text); new userDA().Delete(code); } else { MessageBox.Show("请先选中，再删除！"); } List<userDate> list = new userDA().Select2(); Binding(list); }userDA类：
public void Delete(int code)
{ _Conn.Open(); _Cmd = _Conn.CreateCommand(); _Cmd.CommandText = "delete from table1 where code="+code;_Cmd.ExecuteNonQuery();
_Conn.Close();
}1.点击删除时： 2.点击删除后：