【TeeChart .NET教程】（七）使用函數(shù)

【下載TeeChart.Net最新版本】

（一）功能類型

1.1 功能類型

TeeChart Pro功能是一個系列，幾乎可以是任何系列類型，應(yīng)用代數(shù)功能，數(shù)據(jù)源是另一個圖表系列。所有函數(shù)都派生自Steema.TeeChart.Functions命名空間中的Function類，并繼承Function的 Period屬性。TeeChart Pro提供以下預(yù)定義功能列表：

多種功能類型僅支持一個輸入系列。但是，可以鏈接鏈接函數(shù)，例如，將圖表中多個系列的平均值創(chuàng)建為平均函數(shù)系列，然后使用平均函數(shù)作為趨勢函數(shù)的輸入來標識平均值的趨勢。

添加功能

使用TeeChart Editor，在First Chart頁面上，選擇Add按鈕，就像將新系列添加到Chart中一樣。在TeeChart Gallery中，選擇Functions選項卡以選擇所需的功能。每個功能都顯示為一個系列，用戶可以稍后通過選擇第一個圖表頁面上的更改按鈕來更改與該功能關(guān)聯(lián)的系列類型。之后，在函數(shù)系列的“數(shù)據(jù)源”頁面上可以輕松更改函數(shù)定義。在這里，同樣容易，用戶可以將已添加到Chart的正常Series的定義更改為Function的定義（Function實際上是數(shù)據(jù)源的定義，而不是Series Type的定義）。下圖顯示了編輯函數(shù)時的“數(shù)據(jù)源”頁面。線系列（標題“line2”）已定義。數(shù)據(jù)源頁面底部的左側(cè)列表框顯示了可供輸入的圖表中的其他系列（此處為“line1”）。

從一個完全空的Chart開始，這里是代碼中用于構(gòu)建簡單的Series-Function相關(guān)Chart的步驟。

[C#.Net]

private void Form1_Load(object sender, System.EventArgs e) 
 
 
            //Add a data Series 
            Line line1 = new Line(tChart1.Chart); 
 
            //Populate it with data (here random) 
            line1.FillSampleValues(10); 
 
            //Add a series to be used for an Average Function 
            Line line2 = new Line(tChart1.Chart); 
 
            //Define the Function Type for the new Series 
            Steema.TeeChart.Functions.Average average1 = new Steema.TeeChart.Functions.Average(); 
            line2.Function = average1; 
 
            //Define the Datasource for the new Function Series 
            line2.DataSource = line1; 
 
            //*Note - When populating your input Series manually you will need to  
            //use the Checkdatasource method  
            //- See the section entitled 'Defining a Datasource' 
            //Change the Period of the Function so that it groups averages 
            //every 2 Points 
            line2.Function.Period = 2; 
            line2.CheckDataSource(); 

[VB.Net]

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
        'Add a data Series 
        Dim Line1 As New Steema.TeeChart.Styles.Line(TChart1.Chart) 
         
        'Populate it with data (here random) 
        Line1.FillSampleValues(10) 
 
        'Add a series to be used for an Average Function 
        Dim Line2 As New Steema.TeeChart.LineSeries(TChart1.Chart) 
 
        'Define the Function Type for the new Series 
        Dim Average1 As New Steema.TeeChart.Functions.Average() 
        Line2.Function = Average1 
 
        'Define the Datasource for the new Function Series 
        Line2.DataSource = Line1 
 
        '*Note - When populating your input Series manually you will need to  
        'use the Checkdatasource method  
        '- See the section entitled 'Defining a Datasource' 
        'Change the Period of the Function so that it groups averages 
        'every 2 Points 
        Line2.Function.Period = 2 
        Line2.CheckDataSource() 
End Sub

添加另一個函數(shù)來獲取有關(guān)前一個函數(shù)的信息

[C#.Net]

private void button1_Click(object sender, System.EventArgs e) 
         
            //Let's change to 2D for visibility 
            tChart1.Aspect.View3D = false; 
            //Add another Series to be used for a 2nd Function  
            Line line3 = new Line(tChart1.Chart); 
            //Define the Function Type for the new Series  
            Steema.TeeChart.Functions.High high1 = new Steema.TeeChart.Functions.High(); 
            line3.Function = high1; 
            //Define the Datasource for the new Function Series  
            //Use the existing Function (Series2) as input  
            line3.DataSource = tChart1.Series[1]; 
            //Leave the Period at default 0 (No Period set) to draw  
            //A line at Highest of all points of the Average Function 

[VB.Net]

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 
        'Let's change to 2D for visibility 
        TChart1.Aspect.View3D = False 
        'Add another Series to be used for a 2nd Function  
        Dim Line3 As New Steema.TeeChart.LineSeries(TChart1.Chart) 
        'Define the Function Type for the new Series  
        Dim High1 As New Steema.TeeChart.Functions.High() 
        Line3.Function = High1 
        'Define the Datasource for the new Function Series  
        'Use the existing Function (Series2) as input  
        Line3.DataSource = TChart1.Series(1) 
        'Leave the Period at default 0 (No Period set) to draw  
        'A line at Highest of all points of the Average Function  
End Sub

1.2 定義數(shù)據(jù)源

上一節(jié)中的示例重點介紹如何使用Datasource通過代碼填充Function。Series使用datasource定義Function的輸入或定義Series ADO.NET數(shù)據(jù)源。使用TeeChart編輯器，在添加函數(shù)后，函數(shù)系列的“Datasource”頁面將顯示包含在函數(shù)定義中的可用系列列表。可以更改要應(yīng)用于系列的函數(shù)類型，并從左側(cè)列表框“Available”中選擇系列，并將它們添加到右側(cè)列表框“Selected”，按代碼的數(shù)據(jù)源使用Series.Datasource屬性。

例;

假設(shè)在設(shè)計時通過TeeChart編輯器添加了2個數(shù)據(jù)系列，添加了一個由2系列的平均值組成的函數(shù)：

[C#.Net]

private void Form1_Load(object sender, System.EventArgs e) 
         
            tChart1.Aspect.View3D = false; 
            bar1.FillSampleValues(10); 
            bar2.FillSampleValues(10); 
         
 
        private void button1_Click(object sender, System.EventArgs e) 
         
            Steema.TeeChart.Styles.Line line1 = new Steema.TeeChart.Styles.Line(tChart1.Chart); 
            Steema.TeeChart.Functions.Average average1 = new Steema.TeeChart.Functions.Average();  
            line1.DataSource = new object[]  this.bar2,this.bar1; 
            line1.Function = average1; 
            line1.Marks.Visible = true; 

[VB.Net]

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
        TChart1.Aspect.View3D = False 
        Bar1.FillSampleValues(10) 
        Bar2.FillSampleValues(10) 
End Sub 
 
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 
        Dim DataSource As New ArrayList() 
 
        DataSource.Add(Bar1) 
        DataSource.Add(Bar2) 
 
        Dim Line1 As New Steema.TeeChart.Styles.Line(TChart1.Chart) 
        Dim Average1 As New Steema.TeeChart.Functions.Average() 
 
        Line1.Function = Average1 
        Line1.DataSource = DataSource 
End Sub

為2系列添加點數(shù)：

[C#.Net]

private void button2_Click(object sender, System.EventArgs e) 
         
            Random rnd = new Random(); 
            for(int i = 0; i < 10; ++i) 
             
                bar1.Add(rnd.Next(500)); 
                bar2.Add(rnd.Next(500)); 

[VB.Net]

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click 
        Dim rnd As New Random() 
        Dim i As Integer 
        For i = 0 To 10 
            Bar1.Add(rnd.Next(500)) 
            Bar2.Add(rnd.Next(500)) 
        Next 
End Sub

請注意，該功能不會顯示，需要在Button2_Click（）事件中添加Series.CheckDatasource方法以讀取Function的值。

[C#.Net]

tChart1.Series [2] .CheckDataSource（）;  

[VB.Net]

TChart1.Series（2）.CheckDataSource（）

可以在運行時更改函數(shù)定義，只需重新定義Series.DataSource屬性即可為系列分配新函數(shù)：

[C#.Net]

private void button3_Click(object sender, System.EventArgs e) 
         
            Steema.TeeChart.Functions.Cumulative cumulative1 = new Steema.TeeChart.Functions.Cumulative(); 
            tChart1.Series[2].Function = cumulative1;

[VB.Net]

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click 
        Dim Cumulative1 As New Steema.TeeChart.Functions.Cumulative() 
        TChart1.Series(2).Function = Cumulative1 
End Sub

1.3 功能周期

周期是使用函數(shù)的重要屬性，因為周期定義了循環(huán)應(yīng)用函數(shù)的點的范圍。

示例

有6個數(shù)據(jù)點（例如條形系列的條形），其值為： 3,8,6,2,9和12。定義一個具有周期0的函數(shù)系列（默認），繪制的平均值為：6.667。將周期設(shè)置為2我們得到3個平均值作為函數(shù)的輸出：5.5,4和10.5。這些值將在它們的周期范圍中集中繪制，即輸入系列的第1和第2條之間的第1個值，第3和第4個條之間的第2個值等..通過在“Datasource”頁面中選擇相關(guān)的“Series and Function”并單擊“Options”選項卡來定義“Period ”，也可以使用“FunctionType”在運行時修改“Period ”。

例如，line1是函數(shù)系列：

[C#.Net]

line1.Function.Period = 2;

[VB.Net]

Line1.Function.Period = 2 

下面是2個圖表突出顯示應(yīng)用的周期

1.4 時間段樣式

周期的效果可以定義為范圍，這在使用DateTime系列時非常有用，將函數(shù)的“Period”表示為TimeStep，屬性“PeriodStyle”控制如何表達“Period”。例如，可以使用日期時間源系列上的常規(guī)“Average”功能繪制“monthly average of sales”功能，并將功能期間設(shè)置為“one month”：

[C#.Net]

private void Form1_Load(object sender, System.EventArgs e)  
            //Add in a BarSeries and Average Function at design-time. 
            Random rnd = new Random(); 
            tChart1.Aspect.View3D = false;   
            
            TimeSpan month = new TimeSpan(30,0,0,0); 
            DateTime today = DateTime.Today; 
 
            bar1.Marks.Visible = false; 
            bar1.XValues.DateTime = true; 
            tChart1.Axes.Bottom.Labels.Angle = 90; 
 
            for(int i = 0; i < 60; ++i)  
                today = today.AddDays(5); 
                bar1.Add(today, rnd.Next(100),"",Color.Red); 
             
 
            average1.PeriodAlign = Steema.TeeChart.Functions.PeriodAligns.First; 
            average1.PeriodStyle = Steema.TeeChart.Functions.PeriodStyles.Range; 
            average1.Period = month.TotalDays; 
            line1.DataSource = bar1; 
            line1.CheckDataSource(); 

[VB.Net]

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 
        'Add in a BarSeries and Average Function at design-time. 
        TChart1.Aspect.View3D = False 
 
        Dim Month As New TimeSpan(30, 0, 0, 0) 
        Dim Today As DateTime = DateTime.Today 
        Dim i As Integer 
 
        Bar1.Marks.Visible = False 
        Bar1.XValues.DateTime = True 
        TChart1.Axes.Bottom.Labels.Angle = 90 
 
        For i = 0 To 60 
            Today = Today.AddDays(5) 
            Bar1.Add(Today, Rnd() * 100, "", Color.Red) 
        Next 
 
        Average1.PeriodAlign = Steema.TeeChart.Functions.PeriodAligns.First 
        Average1.PeriodStyle = Steema.TeeChart.Functions.PeriodStyles.Range 
        Average1.Period = Month.TotalDays 
        Line1.DataSource = Bar1 
        Line1.CheckDataSource() 
End Sub 

這將產(chǎn)生幾個點，每個點顯示BarSeries中每個月數(shù)據(jù)的“average”，在計算日期時間段的函數(shù)時，必須按源日期對源系列中的點進行排序，該范圍也可用于非日期時間序列：

[C#.Net]

for(int i = 0; i < 60; ++i)  
     bar1.Add(Convert.ToDouble(i), rnd.Next(100),"",Color.Red); 
 
average1.PeriodAlign = Steema.TeeChart.Functions.PeriodAligns.First; 
average1.PeriodStyle = Steema.TeeChart.Functions.PeriodStyles.Range; 
average1.Period = 6;

[VB.Net]

For i = 0 To 60 
   Bar1.Add(i, Rnd() * 100, "", Color.Red) 
Next 
Average1.PeriodAlign = Steema.TeeChart.Functions.PeriodAligns.First 
Average1.PeriodStyle = Steema.TeeChart.Functions.PeriodStyles.Range 
Average1.Period = 6 

這將計算每個“6”區(qū)間內(nèi)每組點的平均值。（X > = 6，X < 6的點將用于計算第一個平均值，X> = 6的點，X < 12將用于計算第二個平均值，依此類推......），這與計算每6個點的平均值不同。使用“周期對齊”屬性可以對齊“系列&rdquo;范圍內(nèi)的功能點，以下將繪制每月結(jié)束時的功能點：

[C#.Net]

average1.PeriodAlign = Steema.TeeChart.Functions.PeriodAligns.First; 
average1.PeriodStyle = Steema.TeeChart.Functions.PeriodStyles.Range; 
average1.Period = month.TotalDays;

[VB.Net]

Average1.PeriodAlign = Steema.TeeChart.Functions.PeriodAligns.First 
Average1.PeriodStyle = Steema.TeeChart.Functions.PeriodStyles.Range 
Average1.Period = Month.TotalDays

Period = Month.TotalDays and PeriodAligns.First，從下圖中可以看出，“average”是在月末繪制的。

Period = Month.TotalDays and PeriodAligns.Last，在這種情況下，“average”是在月初繪制的。

1.5 派生自定義函數(shù)

創(chuàng)建新的Function組件只是創(chuàng)建一個派生自Function類的新組件（它也可以從現(xiàn)有的函數(shù)類派生），F(xiàn)unction中有兩個重要的虛擬方法可以重寫以創(chuàng)建新的Function類型。 1）Function.Calculate：public virtual double Calculate（Series Source，int First，int Last） 2）Fu??nction.CalculateMany：public virtual double CalculateMany（ArrayList SourceSeries，int ValueIndex） 如果只有一個系列用作數(shù)據(jù)源，則Calculate方法用于計算函數(shù)結(jié)果。如果多個系列可用作數(shù)據(jù)源，則CalculateMany用于計算函數(shù)結(jié)果。

示例：創(chuàng)建新的SquareSum功能，需要一個SquareSum函數(shù)來返回“sum of squares（平方和）”，此函數(shù)只能有一個數(shù)據(jù)源或多個數(shù)據(jù)源，因此我們將覆蓋Calculate和CalculateMany方法。

[C#.Net]

public class SquareSum : Steema.TeeChart.Functions.Function  
        public SquareSum(): base()  
        public SquareSum(Steema.TeeChart.Chart c): base(c)  
 
        public override double Calculate(Series SourceSeries,int FirstIndex,int LastIndex)   
            ValueList v=ValueList(SourceSeries); 
            if ( FirstIndex==-1 ) return v.Total; 
            else  
                double result=0; 
                for (int t=FirstIndex; t<=LastIndex; t++)   
                    result+=Math.Sqrt(v[t]); 
                return result; 
             
         
 
        public override double CalculateMany(ArrayList SourceSeriesList,int ValueIndex)  
            ValueList v; 
            double result=0; 
 
            for (int t=0; tValueIndex )   
                    result+=Math.Sqrt(v[ValueIndex]); 
             
            return result;

[VB.Net]

Public Class SquareSum 
        Inherits Steema.TeeChart.Functions.Function 
 
        Public Sub New() 
            MyBase.New() 
        End Sub 
 
        Public Sub New(ByVal c As Steema.TeeChart.Chart) 
            MyBase.New(c) 
        End Sub 
 
        Public Overrides Function Calculate(ByVal Source As Steema.TeeChart.Series, ByVal First As Integer, ByVal Last As Integer) As Double 
            Dim v As Steema.TeeChart.ValueList 
            Dim t As Integer 
            v = ValueList(Source) 
 
            If First = -1 Then 
                Return v.Total 
            Else 
                Dim Result As Double = 0 
                For t = First To t < Last 
                    Result += Math.Sqrt(v(t)) 
                Next 
                Return Result 
            End If 
        End Function 
 
        Public Overrides Function CalculateMany(ByVal SourceSeries As System.Collections.ArrayList, ByVal ValueIndex As Integer) As Double 
            Dim v As Steema.TeeChart.ValueList 
            Dim Result As Double = 0 
            Dim t As Integer 
 
            For t = 0 To t < SourceSeries.Count 
                v = ValueList(CType(SourceSeries(t), Steema.TeeChart.Series)) 
                If v.Count > ValueIndex Then 
                    Result += Math.Sqrt(v(ValueIndex)) 
                End If 
            Next 
 
            Return Result 
        End Function 
End Class

FirstIndex和EndIndex變量用于“loop（循環(huán)）”所有SourceSeries點以計算平方和。“ValueList”方法用于提取必需的Steema.TeeChart.ValueList，以使這些類與HorizBarSeries等Series類型一起使用，其中“XValues”保存點值而不是“YValues”，當(dāng)Series只有一個Series作為DataSource時，使用“Calculate”方法，當(dāng)Series有多個Series作為數(shù)據(jù)源時，將調(diào)用“CalculateMany”方法。對于源系列中的每個點，“CalculateMany”將被調(diào)用一次，從零開始，以所有數(shù)據(jù)源的最小點數(shù)結(jié)束。理解Calculate和CalculateMany之間的區(qū)別非常重要，當(dāng)只有一個數(shù)據(jù)源并且只調(diào)用一次時調(diào)用“Calculate”。當(dāng)有多個Series作為數(shù)據(jù)源時，會多次調(diào)用“CalculateMany”（每個點一個）。