如何定义数据源的布局

Question

我有一个C#程序，它需要显示一个包含2个序列对象的图表。目前，我只有一个包含2个数据表的数据集。这两张表的布局相同。我将数据集绑定到图表的datasource属性，并执行databind（）方法。它只显示一个系列。

我认为解决方案在于定义一个自定义绑定上下文，但我似乎无法理解。有人能帮帮我吗？谢谢

以下是我的一些代码：

        DataSet dataSet = new DataSet();
        DataTable dataTable = database.Query("select sum(amount) as monthamount, month(transdate) as month from transaction where year(transdate)=" + balanceDateTimePicker.Value.Year + " group by month");
        dataSet.Tables.Add(dataTable);
        dataTable = database.Query("select sum(amount) as monthamount, month(transdate) as month from transaction where year(transdate)=" + balanceDateTimePicker.Value.AddYears(-1).Year + " group by month");
        dataSet.Tables.Add(dataTable);
        reoccuranceChart.DataSource = dataSet;
        System.Windows.Forms.DataVisualization.Charting.Series series = reoccuranceChart.Series["Series1"];
        series.XValueMember = "month";
        series.YValueMembers = "monthamount";
        series.ChartType = System.Windows.Forms.DataVisualization.Charting.SeriesChartType.Column;
        series.IsVisibleInLegend = false;
        series = reoccuranceChart.Series["Series2"];
        series.XValueMember = "month";
        series.YValueMembers = "monthamount";
        series.ChartType = System.Windows.Forms.DataVisualization.Charting.SeriesChartType.Column;
        series.IsVisibleInLegend = false;
        reoccuranceChart.DataBind();

Answer 1

我找到了它。它实际上相当简单。我所要做的就是，单独绑定系列。点：

        DataSet dataSet = new DataSet();
        DataTable dataTable = database.Query("select sum(amount) as monthamount, month(transdate) as month from transaction where year(transdate)=" + balanceDateTimePicker.Value.Year + " group by month");
        dataSet.Tables.Add(dataTable);
        dataTable = database.Query("select sum(amount) as monthamount, month(transdate) as month from transaction where year(transdate)=" + balanceDateTimePicker.Value.AddYears(-1).Year + " group by month");
        dataSet.Tables.Add(dataTable);
        System.Windows.Forms.DataVisualization.Charting.Series series = reoccuranceChart.Series["Now"];
        series.ChartType = System.Windows.Forms.DataVisualization.Charting.SeriesChartType.Column;
        //series.IsVisibleInLegend = false;
        series.Points.DataBind(dataSet.Tables[0].DefaultView, "month", "monthamount", "");
        series = reoccuranceChart.Series["Last year"];
        series.ChartType = System.Windows.Forms.DataVisualization.Charting.SeriesChartType.Column;
        //series.IsVisibleInLegend = false;
        series.Points.DataBind(dataSet.Tables[1].DefaultView, "month", "monthamount", "");

Answer 2

我认为您的问题在于重用dataTable变量。您需要为第二个查询创建第二个DataTable，以防止重新分配第一个，因为Add函数不会复制表中的数据，它只是保存对它的引用。请尝试更改：

dataTable = database.Query ...

至

 DataTable dataTable2 = database.Query...

然后将其添加到第二个表中，看看是否修复了它。