WB 小技巧生成流水号生成随机号

前台HTML代码：

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    </div>
        <h1>添加商品</h1>
        <asp:Button ID="Button1" runat="server" Text="姓名" />
        <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
        <br />
        <br />
        <br />
        <asp:Button ID="Button2" runat="server" Text="价格" />
        <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
        <br />
        <br />
        <br />
        <asp:Button ID="Button3" runat="server" Text="添加" OnClick="Button3_Click" />
            
        <asp:Button ID="Button4" runat="server" OnClick="Button4_Click" Text="随机" />
        <br />
    </form>
</body>
</html>

　　后台C#代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void Button3_Click(object sender, EventArgs e)
    {
        //取值
        string name = TextBox1.Text;
        decimal price = Convert.ToDecimal(TextBox2.Text);
        TestDataContext context = new TestDataContext();
        string code = "";
        //流水号的格式 取当前的日期时间 取出他的年月日
        //查商品表有没有Code
        if (context.ShangPin.Count() == 0)
        {
            code = DateTime.Now.ToString("yyyyMMdd") + "001";
        }
        else
        { 
            
            

            //找到数据库Code列最大的数据 截取后三位+1
            string max = context.ShangPin.Max(p=>p.Code);
            //截取字符串
            string max1 = max.Substring(8,3);
            //截取字符串
            string rq = max.Substring(8);
            if (rq == DateTime.Now.ToString("yyyyMMdd")) //如果想等 就是同一天
            {
                //转成整型
                int max2 = Convert.ToInt32(max1);// 若果是同一天 执行
                max2 = max2 + 1;


                if (max2 < 10)
                {
                    code = DateTime.Now.ToString("yyyyMMdd") + "00" + max2;
                }
                else if (max2 < 100)
                {
                    code = DateTime.Now.ToString("yyyyMMdd") + "0" + max2;
                }
                else
                {
                    code = DateTime.Now.ToString("yyyyMMdd") + max2;
                }
            }
               //执行到这

            else  //不是同一天 重新开始
            {
                code = DateTime.Now.ToString("yyyyMMdd") + "001";
            }
        }
        //添加数据  先造一个ShangPin对象
        ShangPin data = new ShangPin();
        //赋值
        data.Code = code;
        data.Name = name;
        data.Price = price;
        
        context.ShangPin.InsertOnSubmit(data);
        context.SubmitChanges();

    }
    protected void Button4_Click(object sender, EventArgs e)
    {
        TestDataContext context = new TestDataContext();
        string name = TextBox1.Text;
        decimal price = Convert.ToDecimal(TextBox2.Text);
        //定义一个随机数
        Random rd = new Random();
        //生成1000以内的以为随机数
        string code = DateTime.Now.ToString("yyyyMMddHHmmss")+rd.Next(1000);
        //添加数据  先造一个ShangPin对象
        ShangPin data = new ShangPin();
        //赋值
        data.Code = code;
        data.Name = name;
        data.Price = price;

        context.ShangPin.InsertOnSubmit(data);
        context.SubmitChanges();
    }
}

　SQL显示：

WB 小技巧 生成流水号 生成随机号

WB 小技巧生成流水号生成随机号