使用变量访问图表

Posted 2023-04-09

【中文标题】使用变量访问图表

【英文标题】：Using a variable to access a chart

【发布时间】：2013-01-28 00:44:23

【问题描述】：

我有一个 C# WinForms 应用程序，它有四个图表控件，用于以图形方式显示一些分析结果。

我的代码适用于每个图表，但是为了提高效率和重用代码，我定义了一个代码块：

创建所需的系列， 从数据库中提取数据并将结果分配给适当的系列 将系列添加到图表中 自定义图表外观。

上述所有操作都是动态完成的，因为数据在设计时不存在。

我希望重用的工作代码是：

// Add both series to the chart.  
ChartName.Series.AddRange(new Series[]  series1, series2 );  

// Cast the chart's diagram to the XYDiagram type, to access its axes.  
XYDiagram diagram = (XYDiagram)ChartName.Diagram; 

我想将ChartName 对象更改为一个变量，我可以传递每个图表以重用代码。类似的东西（注意这不起作用）：-

var VChart = this.Controls.Find(ChartName, true);  

// Add both series to the chart.  
VChart.Series.AddRange(new Series[]  series1, series2 );  

// Cast the chart's diagram to the XYDiagram type, to access its axes.  
XYDiagram diagram = (XYDiagram)VChart.Diagram; 

任何关于如何将变量传递到 ChartName 的想法、提示、技巧等将不胜感激。

完整代码：

    void Generate_Chart()
    
        // Create two stacked bar series.
        Series series1 = new Series("Data", ViewType.Bar);
        Series series2 = new Series("Ben", ViewType.Line);

        try
                            
            using (var cmd = new SQLiteCommand(m_dbConnection))
            for (int i = LoopMin; i < LoopMax; i++)
            
                // Retrieve the actual calculated values from the database
                cmd.CommandText = "SELECT " + Chart_SourceActualValue + " FROM " + Chart_SourceTable + " WHERE Value = " + i + "";
                Chart_SeriesA_Value = Convert.ToInt32(cmd.ExecuteScalar());

                // Retrieve the expected values from the database
                cmd.CommandText = "SELECT " + Chart_BenExpValue + " FROM " + Chart_SourceTable + " WHERE Value = " + i + "";
                Chart_SeriesB_Value = Convert.ToInt32(cmd.ExecuteScalar());

                // Add the dynamically created values to a series point for the chart
                series1.Points.Add(new SeriesPoint(i, Chart_SeriesA_Value));
                series2.Points.Add(new SeriesPoint(i, Chart_SeriesB_Value));
            
        
        catch (Exception)
                        
            throw;
        

        // Add both series to the chart.
        //this.Controls.Find(varChart, true)
        ChartName.Series.AddRange(new Series[]  series1, series2 );

        // Remove the GridLines from the chart for better UI
        // Cast the chart's diagram to the XYDiagram type, to access its axes.
        XYDiagram diagram = (XYDiagram)ChartName.Diagram;
        // Customize the appearance of the axes' grid lines.
        diagram.AxisX.GridLines.Visible = false;
                

【问题讨论】：

“将变量传递到 ChartName”是什么意思？

我使用ref 关键字做了类似的事情来创建泛型方法

我想重新使用一个变量将 ChartName 传递到系列代码段和 XYDiagram 段中。本质上，我希望对所有四个图表都使用相同的两行代码，而不是八行代码做同样的事情，唯一的区别是 ChartName。

把它放到一个以chartName为参数的函数中？

我不确定您使用的是什么图表包，但向前迈出的一步是将您重新获取图表更改为var VChart = this.Controls.Find(ChartName, true).FirstOrDefault(); 。目前您的 Controls.Find 返回一个 Control 数组

【参考方案1】：

听起来您要求将硬编码的ChartName 替换为一个变量，以便您可以在四个不同的时间调用您的例程，每次使用不同的图表。我已经获取了您的代码并替换了图表控件和设置的一些全局变量，并将它们作为您传递给函数的参数：

void Generate_Chart(DevExpress.XtraCharts.ChartControl chartCtrl,
                   string chart_sourceActualValue,
                    string chart_sourceTable,
                   string chart_benExpValue
                   )
    
        // Create two stacked bar series.
        Series series1 = new Series("Data", ViewType.Bar);
        Series series2 = new Series("Ben", ViewType.Line);

        try
                            
            using (var cmd = new SQLiteCommand(m_dbConnection))
            for (int i = LoopMin; i < LoopMax; i++)
            
                // Retrieve the actual calculated values from the database
                cmd.CommandText = "SELECT " + sourceActualValue + " FROM " + 
                     chart_sourceTable + " WHERE Value = " + i + "";
                Chart_SeriesA_Value = Convert.ToInt32(cmd.ExecuteScalar());

                // Retrieve the expected values from the database
                cmd.CommandText = "SELECT " + chart_benExpValue + " FROM " + 
                         chart_sourceTable + " WHERE Value = " + i + "";
                Chart_SeriesB_Value = Convert.ToInt32(cmd.ExecuteScalar());

                // Add the dynamically created values 
                // to a series point for the chart
                series1.Points.Add(new SeriesPoint(i, Chart_SeriesA_Value));
                series2.Points.Add(new SeriesPoint(i, Chart_SeriesB_Value));
            
        
        catch (Exception)
                        
            throw;
        

        // Add both series to the chart.
        chartCtrl.Series.AddRange(new Series[]  series1, series2 );

        // Remove the GridLines from the chart for better UI
        // Cast the chart's diagram to the XYDiagram type, to access its axes.
        XYDiagram diagram = (XYDiagram)chartCtrl.Diagram;
        // Customize the appearance of the axes' grid lines.
        diagram.AxisX.GridLines.Visible = false;
                

然后，您最终使用原始值作为参数调用此方法：

void Generate_Chart(ChartName, Chart_SourceActualValue, Chart_SourceTable, 
                    Chart_BenExpValue);

// call it three other times passing in the different specifics for that chart. e.g.
void Generate_Chart(SomeOtherChartName, SomeOtherChart_SourceActualValue, 
                    SomeOhterChart_SourceTable, SomeOtherChart_BenExpValue);

.....