三层架构第二课
【摘要】
三层架构第二课
数据表格的Cell_Click功能
txtDeptId.Enabled = false;
btnUpdate.Enabled = true;
...
三层架构第二课
数据表格的Cell_Click功能
txtDeptId.Enabled = false;
btnUpdate.Enabled = true;
btnAdd.Enabled = false;
btnDel.Enabled = true;
- 1
- 2
- 3
- 4
单元格的行选中属性：FullRowSelect
//单击的时候，选中项改变事件
private void dataGridView1_SelectionChanged(object sender, EventArgs e)
{
txtDeptId.Text = dataGridView1.CurrentRow.Cells[0].Value.ToString();
txtDeptName.Text = dataGridView1.CurrentRow.Cells[1].Value.ToString();
}
- 1
- 2
- 3
- 4
- 5
一.编辑功能
1.1 UI端
//填进去的值是最新的值
dept = new Dept();
dept.DeptId = txtDeptId.Text.Trim();
dept.DeptName = txtDeptName.Text.Trim();
bool result=deptService.updateDept(dept);
if (result)
MessageBox.Show("更新数据成功");
else
MessageBox.Show("更新数据失败");
//调用查询方法;
dataGridView1.DataSource = deptService.refreshData();
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
1.2
二.删除功能
2.1 UI端
DialogResult dialog = MessageBox.Show("您确认是否删除?", "提示", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
if (dialog == DialogResult.Yes) {
dept = new Dept();
dept.DeptId = txtDeptId.Text.Trim();
bool result = deptService.delDept(dept);
if (result)
MessageBox.Show("删除数据成功");
else
MessageBox.Show("删除数据失败");
}else{
}
//调用查询方法;
dataGridView1.DataSource = deptService.refreshData();
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
三.复杂查询
3.0 通用查询
String url = "server=.;database=MyDb;uid=sa;pwd=123456";
//1.链接对象;
SqlConnection conn = new SqlConnection(url);
conn.Open();
//2.SqlCommand
SqlCommand cmd = conn.CreateCommand();
cmd.CommandText = sql;
if (parameters != null)
{
//继续添加参数;
for (int i = 0; i < parameters.Count; i++)
{
cmd.Parameters.Add(parameters[i]);
}
}
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt=new DataTable();
da.Fill(dt);
return dt;
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
3.1 刷新查询
public DataTable refreshData() {
String sql = "select deptId 部门编号,deptName 部门名称 from dept";
return DBHelper.query(sql,null);
}
- 1
- 2
- 3
- 4
3.2 学生表的复杂查询
3.2.1 UI层
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using Model;
using BLL;
namespace UI
{
public partial class frmStu : Form
{
//定义条件
String currContext = "";
StudentService stuService = new StudentService();
public frmStu()
{
InitializeComponent();
}
private void frmStu_Load(object sender, EventArgs e)
{
//向条件下拉框，增加值;
cmbSeaField.Items.Add("学号");
cmbSeaField.Items.Add("姓名");
cmbSeaField.Items.Add("年龄");
cmbSeaField.Items.Add("性别");
cmbSeaField.Items.Add("系部");
}
/// <summary>
/// 查询按钮
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void btnSearch_Click(object sender, EventArgs e)
{
String searchField = "";
if (cmbSeaField.SelectedItem==null) {
MessageBox.Show("请选择查询项目");
return;
}
//根据下拉框进行判断
switch (cmbSeaField.SelectedItem.ToString()) {
case "学号":
searchField = "stuId";break;
case "姓名":
searchField = "stuName"; break;
case "年龄":
searchField = "age"; break;
case "性别":
searchField = "gender"; break;
case "系部":
searchField = "deptName"; break;
}
//条件判断,尽量用equals
if (cmbOp.SelectedItem.ToString() != "类似于")
currContext = searchField + cmbOp.SelectedItem.ToString() + txtSeaContext.Text ;
else
currContext = searchField + " like '%" + txtSeaContext.Text + "%'";
//调用查询
bindGridView();
}
public void bindGridView() {
dgvStuList.DataSource=stuService.queryByCondition(currContext);
}
/// <summary>
/// 选择框的更改事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void cmbSeaField_SelectedIndexChanged(object sender, EventArgs e)
{
//当选项发生更改时，年轻是等值，其他是比较；
cmbOp.Items.Clear();
if (cmbSeaField.SelectedItem.ToString() == "年龄")
{
cmbOp.Items.Add(">");
cmbOp.Items.Add(">=");
cmbOp.Items.Add("=");
cmbOp.Items.Add("<");
cmbOp.Items.Add("<=");
}
else {
cmbOp.Items.Add("=");
cmbOp.Items.Add("类似于");
}
}
}
}
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- 25
- 26
- 27
- 28
- 29
- 30
- 31
- 32
- 33
- 34
- 35
- 36
- 37
- 38
- 39
- 40
- 41
- 42
- 43
- 44
- 45
- 46
- 47
- 48
- 49
- 50
- 51
- 52
- 53
- 54
- 55
- 56
- 57
- 58
- 59
- 60
- 61
- 62
- 63
- 64
- 65
- 66
- 67
- 68
- 69
- 70
- 71
- 72
- 73
- 74
- 75
- 76
- 77
- 78
- 79
- 80
- 81
- 82
- 83
- 84
- 85
- 86
- 87
- 88
- 89
- 90
- 91
- 92
- 93
- 94
- 95
- 96
- 97
3.2.2 BLL层
public class StudentService
{
StudentDao stuDao = new StudentDao();
public DataTable queryByCondition(String context)
{
return stuDao.queryByCondition(context);
}
}
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
3.2.3 DAL层
这层代码需要修改之
public DataTable queryByCondition(String context)
{
String url = "server=.;database=MyDb;uid=sa;pwd=123456";
//1.链接对象;
SqlConnection conn = new SqlConnection(url);
conn.Open();
//2.SqlCommand
SqlCommand cmd = conn.CreateCommand();
String sql = "select * from student s left join dept d on s.deptId=d.deptId";
if (context != "") {
sql += " where " + context;
}
cmd.CommandText = sql;
SqlDataAdapter da = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);
return dt;
}
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
3.2.4 界面演示
文章来源: aaaedu.blog.csdn.net，作者：tea_year，版权归原作者所有，如需转载，请联系作者。
原文链接：aaaedu.blog.csdn.net/article/details/108935924
【版权声明】本文为华为云社区用户转载文章，如果您发现本社区中有涉嫌抄袭的内容，欢迎发送邮件进行举报，并提供相关证据，一经查实，本社区将立刻删除涉嫌侵权内容，举报邮箱：
cloudbbs@huaweicloud.com
- 点赞
- 收藏
- 关注作者
评论（0）