需求：在ASP.NET中，从数据库中导出数据，规定时间内预测出下一个数据，然后蒋数据绘制折线图。
代码：
public partial class Ware1 : System.Web.UI.Page { static string s = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["User"].ToString(); DataClasses1DataContext ds = new DataClasses1DataContext(s); protected void Page_Load(object sender, EventArgs e) {//页面加载时，就开始显示该仓库中存在的货物信息 DengJi DJ = new DengJi(); WareHouse ware = new WareHouse(); var num = from ware1 in ds.WareHouse where ware1.Wnumber == 1 && ware1.Snumber % 2 == 0 select ware1; if (num.Count() > 0) { SqlConnection sd = new SqlConnection(s); string str2 = "select Id,class,company,realnumber,accept_time,nphone,Snum,quality from Dengji where Wnum =" + 1+ " and Status = ‘在库‘"; SqlDataAdapter sda = new SqlDataAdapter(str2, sd); DataSet ds = new DataSet(); sda.Fill(ds, "DengJi"); GridView1.DataSource = ds.Tables[0].DefaultView; GridView1.DataBind(); GridView1.HeaderRow.Cells[0].Text = "ID"; GridView1.HeaderRow.Cells[1].Text = "种类"; GridView1.HeaderRow.Cells[2].Text = "公司名称"; GridView1.HeaderRow.Cells[3].Text = "入库数量"; GridView1.HeaderRow.Cells[4].Text = "入库时间"; GridView1.HeaderRow.Cells[5].Text = "客户电话"; GridView1.HeaderRow.Cells[6].Text = "货架号"; GridView1.HeaderRow.Cells[7].Text = "货损率"; } else { } } protected void Button1_Click(object sender, EventArgs e)//更改温度 、湿度、风速的值 { Temple temple = new Temple(); var num1 = ds.Temple.Count(); temple.Id = num1 + 1; temple.xname = System.DateTime.Now; temple.ytem = double.Parse(DropDownList1.SelectedItem.Text); temple.yhumidity = double.Parse(DropDownList2.SelectedItem.Text); temple.ywind = double.Parse(DropDownList3.SelectedItem.Text); ds.Temple.InsertOnSubmit(temple); ds.SubmitChanges(); } public class GrayModel//灰色预测模型 { private double a0, a1, a2; private int size;//定义数组长度 private double error; public GrayModel() { } public void build(double[] Str) { size = Str.Length;//获取数组Str长度 double[] Str1 = new double[size];//新建一个长度与以知数组长度一致的数组Str1 Str1[0] = Str[0];//把给定数组的第一个元素赋给数组Str1 for (int i = 1; i < size; i++) { Str1[i] = Str[i] + Str1[i - 1];//获取新的数组值，也就是AGO计算 } double[,] a = new double[size - 1, 2];//生成二维数组a double[,] bt = new double[2, size - 1];//生成二维数组bt double[,] y = new double[size - 1, 1];//生成一维数组y for (int i = 0; i < a.GetLength(0); i++)//GetLength(0)是获取行数 { a[i, 0] = -(Str1[i] + Str1[i + 1]) / 2; a[i, 1] = 1; bt[0, i] = a[i, 0]; bt[1, i] = 1; y[i, 0] = Str[i + 1]; } double[,] t = new double[2, 2];//新建矩阵t multiply(bt, a, t);//矩阵bt,a相乘，最后返回矩阵t t = inverse(t);//获取矩阵t的转置矩阵 double[,] t1 = new double[2, size - 1];//新建矩阵t1 multiply(t, bt, t1); double[,] t2 = new double[2, 1];//新建矩阵t2 multiply(t1, y, t2); a0 = t2[0, 0]; double u = t2[1, 0]; a2 = u / a0; a1 = Str[0] - a2; a0 = -a0; error = 0; for (int i = 0; i < Str.Length; i++) { double d = (Str[i] - GetStr(i)); error += d * d; } error /= Str.Length; } public double GetError()//误差 { return error; } double GetStr1(int k) { return a1 * Math.Exp(a0 * k) + a2; } double GetStr(int k)//返回a0 * a1 * Math.exp(a0 * k); { if (k == 0) return double.Parse((a1 * Math.Exp(a0 * k) + a2).ToString("0.0")); else return double.Parse((a1 * (Math.Exp(a0 * k) - Math.Exp(a0 * (k - 1)))).ToString("0.0")); } public double NextValue(int index)//预测后续的值 { if (index < 0) throw new Exception("超出索引范围"); return GetStr(size + index); } public double nextValue()//返回预测值 { return NextValue(0); } static double[,] inverse(double[,] t)//求矩阵t的逆矩阵 { double[,] a = new double[2, 2]; double det = t[0, 0] * t[1, 1] - t[0, 1] * t[1, 0]; a[0, 0] = t[1, 1] / det; a[0, 1] = -t[1, 0] / det; a[1, 0] = -t[0, 1] / det; a[1, 1] = t[0, 0] / det; return a; } static void multiply(double[,] left, double[,] right, double[,] dest)//两个矩阵相乘 { int first1 = left.GetLength(0);//获取第一个数组的第一维长度，也就是行数 int first2 = left.GetLength(1);//获取第一个数组的二维长度，也就是列数 int second1 = right.GetLength(1);//获取第二个数组的列数 for (int k = 0; k < first1; k++) { for (int j = 0; j < second1; j++) { dest[k, j] = 0; for (int i = 0; i < first2; i++) { dest[k, j] += left[k, i] * right[i, j]; } } } } } protected void Timer1_Tick(object sender, EventArgs e) { //绘制图表 Chart1.ChartAreas["ChartArea1"].AxisY.Maximum = System.Double.NaN; Chart1.ChartAreas["ChartArea1"].AxisY.Minimum = System.Double.NaN; //Chart1.ChartAreas["ChartArea1"].AxisX.Interval = 5; Series series = new Series("温度");//设置图表类型,绘制温度表 series.ChartType = SeriesChartType.Line;//设置曲线样式 Temple temple = new Temple(); series.BorderWidth = 1;//线粗 series.ShadowOffset = 1; int i = 0; int j = 0; var temple1 = from r in ds.Temple where r.Id > ds.Temple.Max(p => p.Id) - 10 //orderby r.Id descending select r.ytem; //从数据库中获取10个数字 //var tem = from r in ds.Temple select r.ytem;//查找温度值，在点上表明数字 foreach (var templ1 in temple1) { series.Points.AddY(templ1); series.Points[i].Label = templ1.ToString(); i++; }//将温度值作为y值，并且在该点标识出温度值 var xna = from r in ds.Temple where r.Id > ds.Temple.Max(p => p.Id) - 10 //orderby r.Id descending select r.xname;//查找时间值 foreach (var xna12 in xna) { series.Points[j].AxisLabel = xna12.ToString(); ; j++; }//将时间值作为x轴的值 Series series1 = new Series("风速");//绘制风速图 series1.ChartType = SeriesChartType.Spline;//曲线样式 series1.BorderWidth = 1; series1.ShadowOffset = 1; int a = 0; var wind = from r in ds.Temple where r.Id > ds.Temple.Max(p => p.Id) - 10 //orderby r.Id descending select r.ywind; //var win = from r in ds.Temple select r.ywind;//y的值 foreach (var wind1 in wind) { series1.Points.AddY(wind1); series1.Points[a].Label = wind1.ToString(); a++; }//获取y的值，并显示出y值 Series series2 = new Series("湿度");//绘制湿度图 series2.ChartType = SeriesChartType.Spline; series2.BorderWidth = 1; series2.ShadowOffset = 1; int c = 0; var humity1 = from r in ds.Temple where r.Id > ds.Temple.Max(p => p.Id) - 10 //orderby r.Id descending select r.yhumidity; //var hum1 = from h in ds.Temple select h.yhumidity;//y的值 foreach (var h1 in humity1) { series2.Points.AddY(h1); series2.Points[c].Label = h1.ToString(); c++; } series1.YAxisType = AxisType.Primary; Chart1.Series.Add(series); Chart1.Series.Add(series1); Chart1.Series.Add(series2);//在图表中显示出曲线 //进行预测数据的前期获取 Temple tem1 = new Temple(); var temp1 = from r in ds.Temple where r.Id > ds.Temple.Max(p => p.Id) - 20 select new { ytem1=r.ytem, win1=r.ywind, hum1=r.yhumidity }; //List<double> array = new List<double>(); double[] array = new double[0];//新建数组 foreach (var num1 in temp1) { double p = num1.ytem1; array = array.Concat(new double[] { p }).ToArray(); }//将获取的数据保存在array中 double[] array1 = new double[0]; foreach (var num2 in temp1) { array1 = array1.Concat(new double[] { num2.win1 }).ToArray(); } double[] array2 = new double[0]; foreach(var num3 in temp1) { array2 = array2.Concat(new double[] { num3.hum1 }).ToArray(); } //预测数据的计算 GrayModel gm = new GrayModel();//调用灰色预测模型进行温度数据预测 gm.build(array); tem1.ytem = gm.nextValue(); GrayModel gm1 = new GrayModel(); gm1.build(array1); tem1.ywind = gm1.nextValue(); GrayModel gm2 = new GrayModel(); gm2.build(array2); tem1.yhumidity = gm2.nextValue(); var q = ds.Temple.Count(); tem1.Id = q + 1; tem1.xname = System.DateTime.Now; ds.Temple.InsertOnSubmit(tem1);//将时间，学列，温度，湿度，风速数据保存在数据库中 ds.SubmitChanges(); // this.Label1.Text = System.DateTime.Now.ToString(); }
上面代码的说明：从数据库中获取了指定数量 的数据，然后使用灰色预测模型预测出新的数据，最后将显示出10个数据的折线图。