需求:连接数据库,在网页上显示一行数据,总共十列,每两秒刷新一次,刷新时数据往前流动(后一个单元格覆盖前一个单元格,最后一个单元格生成一个随机数)
新建项目:
删除:
重建:
放入工具:
设置居中:
新建数据库:
新建表:
建表之后更新数据库:
更新好了之后点击刷新:
刷新后:
右键randomT,在菜单里选择显示表数据,进入如下窗口:
手动键入第一行数据,再点击第二行任一格,完成第一行数据的添加:
右键mydb.mdf:
点击属性,查看并复制连接字符串:
到web.config中使用:
改成相对路径:
编写Default.aspx.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
showdata();
}
protected void showdata()
{
string connstr = ConfigurationManager.ConnectionStrings["connstr"].ToString();//取出字符串
SqlConnection myconn = new SqlConnection(connstr); //字符串对象化
myconn.Open();//打开数据库
string cmdstr = "select * from randomT";
SqlDataAdapter myda = new SqlDataAdapter(cmdstr, myconn);//sql字符串对数据库处理
DataSet myds = new DataSet();
myda.Fill(myds);//处理完的数据fill到myds
GridView1.DataSource = myds;
GridView1.DataBind();
myds.Dispose();
myda.Dispose();
myconn.Close();
}
}
到此,运行,显示数据:
设置属性:
双击生成事件:
最终编写Default.aspx.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void showdata()
{
string connstr = ConfigurationManager.ConnectionStrings["connstr"].ToString();//取出字符串
SqlConnection myconn = new SqlConnection(connstr); //字符串对象化
myconn.Open();//打开数据库
string cmdstr = "select * from randomT";
SqlDataAdapter myda = new SqlDataAdapter(cmdstr, myconn);//sql字符串对数据库处理
DataSet myds = new DataSet();
myda.Fill(myds);//处理完的数据fill到myds
SqlCommand mycmd = new SqlCommand(cmdstr,myconn);
SqlDataReader mydr = mycmd.ExecuteReader();//读一整行的数据,注意在使用另外一个Execute的时候要将此关掉,不然会报错
int fieldCount = mydr.FieldCount;//得到列数
int[] valueArray = new int[fieldCount];//用来存列值
string[] fieldNames = new string[fieldCount];//用来存列名
for (int i = 0; i < fieldCount; i++)//获取列名
{
fieldNames[i] = mydr.GetName(i).ToString();
}
for (int i = 0; i < fieldCount; i++)//获取列值
{
valueArray[i] = Convert.ToInt32(myds.Tables[0].Rows[0][i].ToString());
}
mydr.Close();//解放用不到的资源,避免报错
for (int i = 1; i < fieldCount - 1; i++)//从后往前覆盖
{
valueArray[i] = valueArray[i + 1];
}
Random rd = new Random();
valueArray[fieldCount - 1] = rd.Next(0, 101);
//更新数据库
for(int i = 1; i <= fieldCount - 1; i++)
{
string updateStr = @"update randomT set " + fieldNames[i] + " = " + valueArray[i] + "where id=1";
mycmd.CommandText = updateStr;
mycmd.ExecuteNonQuery();
}
GridView1.DataSource = myds;
GridView1.DataBind();
myds.Dispose();
myda.Dispose();
myconn.Close();
}
protected void Timer1_Tick(object sender, EventArgs e)
{
showdata();
}
}
实现每两秒刷新数据: