TeeChart Pro .NET使用教程（2022）：图表面板上的自定义绘图（上）

此次文章为大家TeeChart Pro .NET使用教程中的图表面板上的自定义绘图。

TeeChart 画布

绘图顺序

使用 TeeChart 的 Canvas 方法时，请记住绘图顺序很重要。 在图表上绘制一条线，然后添加系列数据点将导致该线被透支。

有四个主要的图表绘制事件，按顺序排列：

• 画前事件
• BeforeDrawAxes 事件
• BeforeDrawSeries 事件
• AfterDraw 事件

[C#]private bool afterDraw;private bool beforeDraw;private bool beforeDrawAxis;private bool beforeDrawSeries;private void Form1_Load(object sender, System.EventArgs e) {      SetFlags(ref beforeDraw);     Bar bar1 = new Bar(tChart1.Chart);     bar1.FillSampleValues(20);     radioButton1.Checked = true;}private void SetFlags(ref bool Flag) {     beforeDraw = false;     afterDraw = false;     beforeDrawAxis = false;     beforeDrawSeries = false;     Flag = true;}private void DrawShape(Steema.TeeChart.Drawing.Graphics3D gg) {     gg.Brush.Color = Color.Yellow;     gg.Pen.Visible = true;     gg.Pen.Style = System.Drawing.Drawing2D.DashStyle.Dash;     gg.Brush.Visible = true;     gg.Ellipse(1,1,gg.Chart.Width - 1,gg.Chart.Height - 1);}private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {     if(afterDraw) {     DrawShape(g);    }}private void tChart1_BeforeDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {     if(beforeDraw) {     DrawShape(g);    }}private void tChart1_BeforeDrawAxes(object sender, Steema.TeeChart.Drawing.Graphics3D g) {     if(beforeDrawAxis) {     DrawShape(g);    }}private void tChart1_BeforeDrawSeries(object sender, Steema.TeeChart.Drawing.Graphics3D g) {     if(beforeDrawSeries) {     DrawShape(g);    }}private void radioButton4_Click(object sender, System.EventArgs e) {     SetFlags(ref afterDraw);     tChart1.Refresh();}private void radioButton3_Click(object sender, System.EventArgs e) {     SetFlags(ref beforeDrawSeries);     tChart1.Refresh();}private void radioButton2_Click(object sender, System.EventArgs e) {     SetFlags(ref beforeDrawAxis);     tChart1.Refresh();}private void radioButton1_Click(object sender, System.EventArgs e) {     SetFlags(ref beforeDraw);     tChart1.Refresh();}[VB.Net]Private BeforeDraw As BooleanPrivate BeforeDrawAxis As BooleanPrivate BeforeDrawSeries As BooleanPrivate AfterDraw As BooleanPrivate Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load    SetFlags(BeforeDraw)    Dim Bar1 As New Steema.TeeChart.Styles.Bar(TChart1.Chart)    Bar1.FillSampleValues(20)    RadioButton1.Checked = TrueEnd SubPrivate Sub SetFlags(ByRef Flag As Boolean)    BeforeDraw = False    BeforeDrawAxis = False    BeforeDrawSeries = False    AfterDraw = False    Flag = TrueEnd SubPrivate Sub DrawShape(ByVal gg As Steema.TeeChart.Drawing.Graphics3D)    gg.Brush.Color = Color.Yellow    gg.Pen.Visible = True    gg.Pen.Style = Drawing.Drawing2D.DashStyle.Dash    gg.Brush.Visible = True    gg.Ellipse(1, 1, gg.Chart.Width - 1, gg.Chart.Height - 1)End SubPrivate Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw    If AfterDraw = True Then     DrawShape(g)    End IfEnd SubPrivate Sub TChart1_BeforeDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDraw    If BeforeDraw = True Then     DrawShape(g)    End IfEnd SubPrivate Sub TChart1_BeforeDrawAxes(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDrawAxes    If BeforeDrawAxis = True Then     DrawShape(g)    End IfEnd SubPrivate Sub TChart1_BeforeDrawSeries(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.BeforeDrawSeries    If BeforeDrawSeries = True Then     DrawShape(g)    End IfEnd SubPrivate Sub RadioButton4_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton4.Click    SetFlags(AfterDraw)    TChart1.Refresh()End SubPrivate Sub RadioButton3_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton3.Click    SetFlags(BeforeDrawSeries)    TChart1.Refresh()End SubPrivate Sub RadioButton2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton2.Click    SetFlags(BeforeDrawAxis)    TChart1.Refresh()End SubPrivate Sub RadioButton1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles RadioButton1.Click    SetFlags(BeforeDraw)    TChart1.Refresh()End Sub

确保将自定义绘制的项目保存到 Canvas

如果您没有在图表事件之一中调用 Canvas 绘制代码，自定义绘图将不会永久保存到 Canvas 中，因此当应用程序最小化或将另一个窗口置于其上时，任何添加内容都会丢失。 您的代码不需要直接驻留在图表事件中； 如果您将代码放在 BeforeDrawSeries/AfterDraw 中并检查运行时 Draw 方法设置的标志，从而在活动标记为 true 时运行您的绘制代码，则用户绘制的项目可以在图表窗口的整个生命周期内保存，如上例所示。

画线

让我们添加一个画布线：

[C#]private void Form1_Load(object sender, System.EventArgs e) {        line1.FillSampleValues(20);        line1.VertAxis = VerticalAxis.Both;        line1.HorizAxis = HorizontalAxis.Both;        tChart1.Aspect.View3D = false;}private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {        Point s = new Point(tChart1.Axes.Left.Position, tChart1.Axes.Top.Position);        Point e = new Point(tChart1.Axes.Right.Position, tChart1.Axes.Bottom.Position);        g.MoveTo(s);        g.LineTo(e,0);}[VB.Net]Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load        Line1.FillSampleValues(20)        Line1.VertAxis = Steema.TeeChart.VerticalAxis.Both        Line1.HorizAxis = Steema.TeeChart.HorizontalAxis.Both        TChart1.Aspect.View3D = FalseEnd SubPrivate Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw        Dim S As New Point(TChart1.Axes.Left.Position, TChart1.Axes.Top.Position)        Dim E As New Point(TChart1.Axes.Right.Position, TChart1.Axes.Bottom.Position)        g.MoveTo(S)        g.LineTo(E, 0)End Sub

在 3D 图表上，由于 3D 正交位移，轴位置从图表区域偏移。 我们可以相应地移动线：

[C#]private void Form1_Load(object sender, System.EventArgs e) {        line1.FillSampleValues(20);        line1.VertAxis = VerticalAxis.Both;        line1.HorizAxis = HorizontalAxis.Both;        tChart1.Aspect.Chart3DPercent = 50;}private void tChart1_AfterDraw(object sender, Steema.TeeChart.Drawing.Graphics3D g) {        Steema.TeeChart.Drawing.Point3D s = new Steema.TeeChart.Drawing.Point3D();        s.X = tChart1.Axes.Left.Position;        s.Y = tChart1.Axes.Top.Position;        s.Z = 0;        Steema.TeeChart.Drawing.Point3D e = new Steema.TeeChart.Drawing.Point3D();        e.X = tChart1.Axes.Right.Position;        e.Y = tChart1.Axes.Bottom.Position;        e.Z = tChart1.Aspect.Width3D;        g.MoveTo(s);        g.LineTo(e);}[VB.Net]Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load        Line1.FillSampleValues(20)        Line1.VertAxis = Steema.TeeChart.VerticalAxis.Both        Line1.HorizAxis = Steema.TeeChart.HorizontalAxis.Both        TChart1.Aspect.Chart3DPercent = 50End SubPrivate Sub TChart1_AfterDraw(ByVal sender As Object, ByVal g As Steema.TeeChart.Drawing.Graphics3D) Handles TChart1.AfterDraw        Dim S As New Steema.TeeChart.Drawing.Point3D()        S.X = TChart1.Axes.Left.Position        S.Y = TChart1.Axes.Top.Position        S.Z = 0        Dim E As New Steema.TeeChart.Drawing.Point3D()        E.X = TChart1.Axes.Right.Position        E.Y = TChart1.Axes.Bottom.Position        E.Z = TChart1.Aspect.Width3D        g.MoveTo(S)        g.LineTo(E)End Sub

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