多折线图

Question

我一直在尝试制作一个从数据库中提取数据的多线图。 为了做到这一点，我编写了以下代码来填充图表：

    SqlConnection con1 = new SqlConnection();
    con1.ConnectionString = ConfigurationManager.ConnectionStrings["Removed"].ToString();
    SqlCommand cmd1 = new SqlCommand("SELECT YEAR(Start_Date) AS Year, Month(Start_Date) As Month, Cost, Utility_Type FROM import_Utilities WHERE YEAR(Start_Date) = 2011  AND Utility_Type = 'Water'");
    cmd1.Connection = con1;
    con1.Open();

    SqlDataAdapter da1 = new SqlDataAdapter(cmd1);
    DataTable dt1 = new DataTable();
    da1.Fill(dt1);
    Chart1.DataSource = dt1;

    Chart1.Series["Series2"].XValueMember = "Month";
    Chart1.Series["Series2"].YValueMembers = "Cost";
    Chart1.Legends.Add(new Legend("Default") { Docking = Docking.Right });


    Chart1.DataBind();
    con1.Close();

    SqlConnection con = new SqlConnection();
    con.ConnectionString = ConfigurationManager.ConnectionStrings["Removed"].ToString();
    con.Open();
    SqlCommand cmd = new SqlCommand("SELECT YEAR(Start_Date) AS Year, Month(Start_Date) As Month, Cost, Utility_Type FROM import_Utilities WHERE YEAR(Start_Date) = 2012 AND Utility_Type = 'Water'");
    cmd.Connection = con;
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    da.Fill(dt);
    Chart1.DataSource = dt;
    Chart1.Series["2010"].XValueMember = "Month";
    Chart1.Series["2010"].YValueMembers = "Cost";

    Chart1.DataBind();
    con.Close();

此代码有效，但它有两个数据源，因此只有底部的 sqlconnection 填充到图表中。 我不知道如何解决这个问题，我想他们是解决这个问题的更好方法，但我不知所措。

更新：

使用下面的示例，我最终使用 pivot sql 制作了一个表（见图）。 然后我将我的代码更新为以下内容：

 SqlCommand cmd = new SqlCommand("SELECT * FROM ( SELECT YEAR(Start_Date), CASE MONTH(Start_Date) WHEN 1 THEN 'January' WHEN 2 THEN 'February' WHEN 3 THEN 'March' WHEN 4 THEN 'April' WHEN 5 THEN 'May' WHEN 6 THEN 'June' WHEN 7 THEN 'July' WHEN 8 THEN 'August' WHEN 9 THEN 'September'WHEN 10 THEN 'October' WHEN 11 THEN 'November' WHEN 12 THEN 'December' END as [Month], [Cost] FROM [HousingAccountingReports].[dbo].[import_Utilities] Where [Building] = 'Building B' AND [Utility_Type] = 'Electric') TableDate PIVOT (SUM([Cost]) FOR [Month] IN ([January],[February],[March],[April],[May],[June],[July],[August],[September],[October],[November],[December] )) PivotTable");
    cmd.Connection = con;
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    da.Fill(dt);
    Chart3.DataSource = dt;
    Chart3.Series["Series1"].XValueMember = "Month";
    Chart3.Series["Series1"].YValueMembers = "2010";
    Chart3.Series["Series2"].XValueMember = "Month";
    Chart3.Series["Series2"].YValueMembers = "2011";
    Chart3.Series["Series3"].XValueMember = "Month";
    Chart3.Series["Series3"].YValueMembers = "2012";
    Chart3.DataBind();`

当我运行该页面时，它错误地找不到月份列。如果我添加：
dt.Columns.Add("月"); dt.Columns.Add（“年份”）；` 找不到 2010，我如何让我的图表正确导航；他们是我的pivot sql的问题吗？

Answer 1

我昨天回答了一个类似的问题。 Separating Chart Series

您不能在不重置数据的情况下更改图表数据源，就像在上面的代码中所做的那样。

就像昨天的问题一样，我建议您先创建一个数据表，然后将数据表中的列引用到您的特定系列

昨天的回答

因此，作为清理代码的建议，我将执行以下操作

1. 获取 2 个数据表
2. 以“Month”为主键合并数据表
3. 将每一列作为新系列添加到图表中

或者您可以手动绘制系列

所以放弃

Chart1.DataSource = dt
Chart1.Series["2010"].XValueMember = "Month";
Chart1.Series["2010"].YValueMembers = "Cost";

替换成

For Each row As DataRow In dt1.Rows
     Chart1.Series("Series2").Points.AddXY(row.Item("Month"), row.Item("Cost"))
Next

For Each row As DataRow In dt.Rows
     Chart1.Series("2010").Points.AddXY(row.Item("Month"), row.Item("Cost"))
Next

如果您设法将所有数据放入一个 Datatable 并创建一个包含两个系列的图表，那么您可以执行以下操作

    Dim dt As New DataTable
    dt.Columns.Add("Month", GetType(String))
    dt.Columns.Add("2010", GetType(Integer))
    dt.Columns.Add("2011", GetType(Integer))

    dt.Rows.Add("January", 15, 25)
    dt.Rows.Add("February", 18, 32)
    dt.Rows.Add("March", 12, 34)
    dt.Rows.Add("April", 12, 34)

    Chart1.DataSource = dt
    Chart1.Series(0).XValueMember = "Month"
    Chart1.Series(0).YValueMembers = "2010"

    Chart1.Series(1).XValueMember = "Month"
    Chart1.Series(1).YValueMembers = "2011"

    Chart1.DataBind()

根据您的代码，我的理解应该是这样的：

SqlConnection con = new SqlConnection();
        con.ConnectionString = ConfigurationManager.ConnectionStrings["removed"].ToString();
        con.Open();
        SqlCommand cmd = new SqlCommand("SELECT YEAR(Start_Date) AS Year, Month(Start_Date) As Month, Cost, Utility_Type, Building FROM import_Utilities WHERE YEAR(Start_Date) = 2012 AND YEAR(Start_Date) = 2011 AND Utility_Type = 'Water'");

        cmd.Connection = con;
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        da.Fill(dt);

    Chart1.DataSource = dt;
    Chart1.Series(0).XValueMember = "Month";
    Chart1.Series(0).YValueMembers = "2010";

    Chart1.Series(1).XValueMember = "Month";
    Chart1.Series(1).YValueMembers = "2011"

    Chart1.DataBind()

数据表 dt 中应该包含所有数据{因为我都在铭记这两年）（我如何将它绑定到表以便我可以验证）

但是现在它的抱怨系列不能用作一种方法。

我是一个新手程序员，只在空闲时间做这件事，所以请原谅我的简单错误。

我是否需要像您在此处那样设置数据表： Chart1.DataSource = dt; Chart1.Series(0).XValueMember = "月"; Chart1.Series(0).YValueMembers = "2010";

    Chart1.Series(1).XValueMember = "Month";
    Chart1.Series(1).YValueMembers = "2011"

    Chart1.DataBind()

还是根据sql表做的？