DataGridView连接Sql数据库 功能 查询 添加 删除 修改

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 System.Data.SqlClient;
namespace _03大项目
{
public partial class Form1 : Form
{
//连接字符串
string str = "Data Source=.;Initial Catalog=MyDeskInfo;Integrated Security=True";
public Form1()
{
InitializeComponent();
}
//窗体加载
private void Form1_Load(object sender, EventArgs e)
{
//加载餐桌
LoadDeskInfoByDelFlag(0);
}
/// <summary>
/// 该方法是加载所有没有被删除的餐桌
/// </summary>
/// <param name="p">删除标识 0---未删除,1---删除</param>
private void LoadDeskInfoByDelFlag(int p)
{
List<DeskInfo> list = new List<DeskInfo>();

//通过连接字符串连接数据库
using (SqlConnection con = new SqlConnection(str))
{
//拼接sql语句
string sql = "select DeskId,DeskName,DeskNamePinYin,DeskNum from DeskInfo where DeskDelFlag=" + p;
//准备执行sql语句的对象
using (SqlCommand cmd = new SqlCommand(sql, con))
{
con.Open();//打开数据库
//准备读数据
using (SqlDataReader reader = cmd.ExecuteReader())
{
//判断是否有数据(有没有行)
if (reader.HasRows)
{
//读取每一行
while (reader.Read())
{
DeskInfo dk = new DeskInfo();//创建餐桌对象
dk.DeskId = Convert.ToInt32(reader["DeskId"]);//id
dk.DeskName = reader["DeskName"].ToString();//名字
dk.DeskNamePinYin = reader["DeskNamePinYin"].ToString();//拼音
dk.DeskNum = reader["DeskNum"].ToString();//编号
list.Add(dk);//添加到集合中
}//end while
}//end if
}// end sqldatareader
}//end using
}//end using

dgv.AutoGenerateColumns = false;//禁止自动生成列
dgv.DataSource = list;//绑定数据 到集合list，这样才有显示
dgv.SelectedRows[0].Selected = false;//禁止被选中

}
//添加数据
private void btnOk_Click(object sender, EventArgs e)
{
int n = -1;
//获取文本框的值
//连接数据库
using (SqlConnection con = new SqlConnection(str))
{
string sql = string.Format("insert into DeskInfo(DeskName, DeskNamePinYin, DeskDelFlag, DeskNum) values('{0}','{1}',{2},'{3}')", txtName.Text, txtPinYin.Text, 0, txtNum.Text);
using (SqlCommand cmd = new SqlCommand(sql, con))
{
con.Open();//打开数据库
n = cmd.ExecuteNonQuery();
}
}
string msg = n > 0 ? "操作成功" : "操作失败";
MessageBox.Show(msg);
LoadDeskInfoByDelFlag(0);//刷新

}

private void btnDelete_Click(object sender, EventArgs e)
{

//判断一下 是否选中行
if (dgv.SelectedRows.Count > 0)
{
int r = -1;
//选中了
//该行数据的id
string strId = dgv.SelectedRows[0].Cells[0].Value.ToString();
int id = Convert.ToInt32(strId);//转换一下
//update DeskInfo set DeskDelFlag=1 where DeskId=

using (SqlConnection con = new SqlConnection(str))
{
string sql = "update DeskInfo set DeskDelFlag=1 where DeskId=" + id;
using (SqlCommand cmd = new SqlCommand(sql, con))
{
con.Open();
r = cmd.ExecuteNonQuery();
}// end using
}//end using

string msg = r > 0 ? "操作成功" : "操作失败";
MessageBox.Show(msg);
LoadDeskInfoByDelFlag(0);//刷新
}
}

private void dgv_CellClick(object sender, DataGridViewCellEventArgs e)
{
if (dgv.SelectedRows.Count>0)
{
//获取这条数据中的每个列中的值
//id  name  pinyin  num
labId.Text = dgv.SelectedRows[0].Cells[0].Value.ToString();
txtUName.Text = dgv.SelectedRows[0].Cells[1].Value.ToString();
txtUPinYin.Text = dgv.SelectedRows[0].Cells[2].Value.ToString();
txtUNum.Text = dgv.SelectedRows[0].Cells[3].Value.ToString();
}

}

private void btnUpdate_Click(object sender, EventArgs e)
{
if (dgv.SelectedRows.Count>0)
{
int r = -1;
//修改
using (SqlConnection con=new SqlConnection(str))
{
string sql =string.Format("update DeskInfo set DeskName='{0}',DeskNamePinYin='{1}',DeskNum='{2}' where DeskId={3}",txtUName.Text,txtUPinYin.Text,txtUNum.Text,Convert.ToInt32(labId.Text));
using (SqlCommand cmd=new SqlCommand(sql,con))
{
con.Open();
r= cmd.ExecuteNonQuery();
}// end using
}// end using
MessageBox.Show(r>0?"操作成功":"操作失败");
LoadDeskInfoByDelFlag(0);
}
}
//显示有多少条数据
private void button1_Click(object sender, EventArgs e)
{
//不要这个
//MessageBox.Show(dgv.SelectedRows.Count);

//练习
object obj;
using (SqlConnection con=new SqlConnection(str))
{
string sql = "select count(*) from DeskInfo where DeskDelFlag=0";
using (SqlCommand cmd=new SqlCommand(sql,con))
{
con.Open();
obj= cmd.ExecuteScalar();
}
}
MessageBox.Show(obj.ToString());

}

private void btnGc_Click(object sender, EventArgs e)
{
//查询的是被删除的数据
LoadDeskInfoByDelFlag(1);
}

private void btnCDDelete_Click(object sender, EventArgs e)
{
string id = dgv.SelectedRows[0].Cells[0].Value.ToString();
//还是 更新  改标识   5 恢复 数据需要再交钱 100 超邪恶的方法
//稍稍的修改一下标识
//  如果有一天 我邪恶了 请记住 我曾纯洁过

int r = -1;
//修改
using (SqlConnection con = new SqlConnection(str))
{
string sql = "update DeskInfo set DeskDelFlag=5";
using (SqlCommand cmd = new SqlCommand(sql, con))
{
con.Open();
r = cmd.ExecuteNonQuery();
}// end using
}// end using
MessageBox.Show(r > 0 ? "操作成功" : "操作失败");
}
}
}