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。我迷失了如何解决这个问题，我想他们这是一个更好的方法，但我不知所措。

更新：

使用下面的示例我最终使用pivot sql来制作表格（见图片）。 Pivot Table 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();`

当我运行页面时，它出错，无法找到列Month。如果我补充：
dt.Columns.Add（＆＃34;月＆＃34）; dt.Columns.Add（＆＃34;年份＆＃34）;` 它找不到2010年，如何让我的图表正确驾驶;我的pivot sql有问题吗？

Answer 1

我昨天回答了类似的问题。 Separating Chart Series

您无法更改图表数据源而无需重置上述代码中的数据。

与昨天的问题一样，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

从昨天回答

因此，建议清理代码，我会执行以下操作


获取2个数据表

将数据表与“月”合并为主键

将每列添加到图表中作为新系列

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";

并将其替换为

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合并到一个Datatable并创建了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()

enter image description here

根据您的代码，这应符合我的理解：

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应该包含其中的所有数据{因为我正在考虑这两年）（如何将其绑定到表以便我可以验证）

现在它的抱怨系列不能用作方法。

我是一名非常新的程序员，只能在我的空闲时间这样做，所以请原谅我的简单错误。

我是否需要像在此处一样设置数据表： 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()

或者它是基于sql表吗？

多线图

1 个答案: