string str = "Data source=.;initial catalog=MySchool;uid=sa;";  //连接数据库SqlConnection con = new SqlConnection(str);string sql = "select count(1) from student where studentname='" + txtname.Text + "' and loginpwd='" + txtpwd.Text + "'";SqlCommand cmd = new SqlCommand(sql, con);try{con.Open();int count = Convert.ToInt32(cmd.ExecuteScalar());//给数据库传值if (count > 0)//判断是否成功,成功COUNT大于0反之你脑子就有病了!!!!!!!!!!{this.Hide();lnlwinds frm = new lnlwinds();frm.Show();}}catch (Exception){MessageBox.Show("脑子有病");}finally{con.Close();}

string pwd = txtpwd.Text;           //获得第一次输入密码string agePqd = txttowpwd.Text;   //获得第二次输入的密码if (agePqd.Equals(pwd)){string name = textname.Text;         //获得用户输入的名字 int grendID = Change();              //获得用户输入年级string phone = textphone.Text;  //获得用户输入的电话string Email = txtEmail.Text;   //获得用户输入的EmailDateTime birthday = time.Value;       //获得用户输入的出生日期string gender = string.Empty;      //获得用户输入的性别if (boy.Checked){gender = "1";}else{gender = "0";}SqlConnection con = null;try{string str = "data source=.;initial catalog=MySchool;user ID=sa;";con = new SqlConnection(str);con.Open();string sql = "insert Student values('" + pwd + "','" + name + "','" + gender + "'," + grendID + ",'" + phone + "','" + birthday + "','" + Email + "');select @@identity";SqlCommand com = new SqlCommand(sql, con);int count = Convert.ToInt32(com.ExecuteScalar());if (count > 0){DialogResult result = MessageBox.Show("添加成功!", "用户提示", MessageBoxButtons.YesNo, MessageBoxIcon.Information);txtstudentnumber.Text = count.ToString();if (result == DialogResult.Yes){this.Close();}}}catch (Exception){MessageBox.Show("添加失败!", "用户提示", MessageBoxButtons.YesNo, MessageBoxIcon.Information);}finally{if (con != null){con.Close();}}}else{MessageBox.Show("两次输入的密码不一致!", "用户提示", MessageBoxButtons.YesNo, MessageBoxIcon.Information);}

DialogResult result=  MessageBox.Show("您确定要清空所填入的数据?","用户提示",MessageBoxButtons.YesNo,MessageBoxIcon.Information);if (result == DialogResult.Yes){txtgrade.SelectedIndex = 0;  //默认年级框的值为第一项  foreach (Control item in register.Controls)    //因为有GroupBox控件,所以要用foreacher
             {if (item is TextBox){item.Text = string.Empty;}}foreach (Control item in message.Controls){if (item is TextBox){item.Text = string.Empty;}}}

 private void button1_Click(object sender, EventArgs e){//查询数据，清空LIstView中的数据
            lvStuList.Items.Clear();string sql = @"select Studentno,Studentname,Gender,gradenamefrom student,gradewhere student.gradeid=grade.gradeid and studentname like '%" + txtname.Text + "%' ";LoadDataFromDBToListView(sql);}private void btnSearch_Load(object sender, EventArgs e){string sql = @"select Studentno,Studentname,Gender,gradenamefrom student,gradewhere student.gradeid=grade.gradeid";LoadDataFromDBToListView(sql);}