TrackBarRenderer Class
Definition
Important
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Provides methods used to render a track bar control with visual styles. This class cannot be inherited.
public ref class TrackBarRenderer sealedpublic ref class TrackBarRenderer abstract sealedpublic sealed class TrackBarRendererpublic static class TrackBarRenderertype TrackBarRenderer = classPublic NotInheritable Class TrackBarRendererPublic Class TrackBarRenderer- Inheritance
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TrackBarRenderer
Examples
The following code example demonstrates how to create a custom control that uses the TrackBarRenderer methods to draw a horizontal track bar that responds to mouse clicks.
#using <System.Drawing.dll>
#using <System.Windows.Forms.dll>
#using <System.dll>
using namespace System;
using namespace System::Drawing;
using namespace System::Windows::Forms;
using namespace System::Windows::Forms::VisualStyles;
namespace TrackBarRendererSample
{
ref class CustomTrackBar : public Control
{
private:
int numberTicks;
Rectangle trackRectangle;
Rectangle ticksRectangle;
Rectangle thumbRectangle;
int currentTickPosition;
float tickSpace;
bool thumbClicked;
TrackBarThumbState thumbState;
public:
CustomTrackBar(int ticks, System::Drawing::Size trackBarSize)
{
this->Location = Point(10, 10);
this->Size = trackBarSize;
this->numberTicks = ticks;
this->BackColor = Color::DarkCyan;
this->DoubleBuffered = true;
numberTicks = 10;
thumbState = TrackBarThumbState::Normal;
// Calculate the initial sizes of the bar,
// thumb and ticks.
SetupTrackBar();
}
// Calculate the sizes of the bar, thumb, and ticks rectangle.
private:
void SetupTrackBar()
{
if (!TrackBarRenderer::IsSupported)
{
return;
}
Graphics^ g = this->CreateGraphics();
// Calculate the size of the track bar.
trackRectangle.X = ClientRectangle.X + 2;
trackRectangle.Y = ClientRectangle.Y + 28;
trackRectangle.Width = ClientRectangle.Width - 4;
trackRectangle.Height = 4;
// Calculate the size of the rectangle in which to
// draw the ticks.
ticksRectangle.X = trackRectangle.X + 4;
ticksRectangle.Y = trackRectangle.Y - 8;
ticksRectangle.Width = trackRectangle.Width - 8;
ticksRectangle.Height = 4;
tickSpace = ((float)ticksRectangle.Width - 1) /
((float)numberTicks - 1);
// Calculate the size of the thumb.
thumbRectangle.Size =
TrackBarRenderer::GetTopPointingThumbSize(g,
TrackBarThumbState::Normal);
thumbRectangle.X = CurrentTickXCoordinate();
thumbRectangle.Y = trackRectangle.Y - 8;
}
private:
int CurrentTickXCoordinate()
{
if (tickSpace == 0)
{
return 0;
}
else
{
return ((int)Math::Round(tickSpace) *
currentTickPosition);
}
}
// Draw the track bar.
protected:
virtual void OnPaint(PaintEventArgs^ e) override
{
if (!TrackBarRenderer::IsSupported)
{
this->Parent->Text = "CustomTrackBar Disabled";
return;
}
this->Parent->Text = "CustomTrackBar Enabled";
TrackBarRenderer::DrawHorizontalTrack(e->Graphics,
trackRectangle);
TrackBarRenderer::DrawTopPointingThumb(e->Graphics,
thumbRectangle, thumbState);
TrackBarRenderer::DrawHorizontalTicks(e->Graphics,
ticksRectangle, numberTicks, EdgeStyle::Raised);
}
// Determine whether the user has clicked the track bar thumb.
protected:
virtual void OnMouseDown(MouseEventArgs^ e) override
{
if (!TrackBarRenderer::IsSupported)
{
return;
}
if (this->thumbRectangle.Contains(e->Location))
{
thumbClicked = true;
thumbState = TrackBarThumbState::Pressed;
}
this->Invalidate();
}
// Redraw the track bar thumb if the user has moved it.
protected:
virtual void OnMouseUp(MouseEventArgs^ e) override
{
if (!TrackBarRenderer::IsSupported)
{
return;
}
if (thumbClicked == true)
{
if (e->Location.X > trackRectangle.X &&
e->Location.X < (trackRectangle.X +
trackRectangle.Width - thumbRectangle.Width))
{
thumbClicked = false;
thumbState = TrackBarThumbState::Hot;
this->Invalidate();
}
thumbClicked = false;
}
}
// Track cursor movements.
protected:
virtual void OnMouseMove(MouseEventArgs^ e) override
{
if (!TrackBarRenderer::IsSupported)
{
return;
}
// The user is moving the thumb.
if (thumbClicked == true)
{
// Track movements to the next tick to the right, if
// the cursor has moved halfway to the next tick.
if (currentTickPosition < numberTicks - 1 &&
e->Location.X > CurrentTickXCoordinate() +
(int)(tickSpace))
{
currentTickPosition++;
}
// Track movements to the next tick to the left, if
// cursor has moved halfway to the next tick.
else if (currentTickPosition > 0 &&
e->Location.X < CurrentTickXCoordinate() -
(int)(tickSpace / 2))
{
currentTickPosition--;
}
thumbRectangle.X = CurrentTickXCoordinate();
}
// The cursor is passing over the track.
else
{
if (thumbRectangle.Contains(e->Location))
{
thumbState = TrackBarThumbState::Hot;
}
else
{
thumbState = TrackBarThumbState::Normal;
}
}
Invalidate();
}
};
ref class Form1 : public Form
{
public:
Form1()
{
CustomTrackBar^ TrackBar1 = gcnew CustomTrackBar(19,
System::Drawing::Size(300, 50));
this->Width = 500;
this->Controls->Add(TrackBar1);
}
};
}
[STAThread]
int main()
{
// Note that the call to EnableVisualStyles below does
// not affect whether TrackBarRenderer.IsSupported is true;
// as long as visual styles are enabled by the operating system,
// IsSupported is true.
Application::EnableVisualStyles();
Application::Run(gcnew TrackBarRendererSample::Form1());
return 0;
}
using System;
using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.VisualStyles;
namespace TrackBarRendererSample
{
class Form1 : Form
{
public Form1()
{
CustomTrackBar TrackBar1 = new CustomTrackBar(19,
new Size(300, 50));
this.Width = 500;
this.Controls.Add(TrackBar1);
}
[STAThread]
static void Main()
{
// Note that the call to EnableVisualStyles below does
// not affect whether TrackBarRenderer.IsSupported is true;
// as long as visual styles are enabled by the operating system,
// IsSupported is true.
Application.EnableVisualStyles();
Application.Run(new Form1());
}
}
class CustomTrackBar : Control
{
private int numberTicks = 10;
private Rectangle trackRectangle = new Rectangle();
private Rectangle ticksRectangle = new Rectangle();
private Rectangle thumbRectangle = new Rectangle();
private int currentTickPosition = 0;
private float tickSpace = 0;
private bool thumbClicked = false;
private TrackBarThumbState thumbState =
TrackBarThumbState.Normal;
public CustomTrackBar(int ticks, Size trackBarSize)
{
this.Location = new Point(10, 10);
this.Size = trackBarSize;
this.numberTicks = ticks;
this.BackColor = Color.DarkCyan;
this.DoubleBuffered = true;
// Calculate the initial sizes of the bar,
// thumb and ticks.
SetupTrackBar();
}
// Calculate the sizes of the bar, thumb, and ticks rectangle.
private void SetupTrackBar()
{
if (!TrackBarRenderer.IsSupported)
return;
using (Graphics g = this.CreateGraphics())
{
// Calculate the size of the track bar.
trackRectangle.X = ClientRectangle.X + 2;
trackRectangle.Y = ClientRectangle.Y + 28;
trackRectangle.Width = ClientRectangle.Width - 4;
trackRectangle.Height = 4;
// Calculate the size of the rectangle in which to
// draw the ticks.
ticksRectangle.X = trackRectangle.X + 4;
ticksRectangle.Y = trackRectangle.Y - 8;
ticksRectangle.Width = trackRectangle.Width - 8;
ticksRectangle.Height = 4;
tickSpace = ((float)ticksRectangle.Width - 1) /
((float)numberTicks - 1);
// Calculate the size of the thumb.
thumbRectangle.Size =
TrackBarRenderer.GetTopPointingThumbSize(g,
TrackBarThumbState.Normal);
thumbRectangle.X = CurrentTickXCoordinate();
thumbRectangle.Y = trackRectangle.Y - 8;
}
}
private int CurrentTickXCoordinate()
{
if (tickSpace == 0)
{
return 0;
}
else
{
return ((int)Math.Round(tickSpace) *
currentTickPosition);
}
}
// Draw the track bar.
protected override void OnPaint(PaintEventArgs e)
{
if (!TrackBarRenderer.IsSupported)
{
this.Parent.Text = "CustomTrackBar Disabled";
return;
}
this.Parent.Text = "CustomTrackBar Enabled";
TrackBarRenderer.DrawHorizontalTrack(e.Graphics,
trackRectangle);
TrackBarRenderer.DrawTopPointingThumb(e.Graphics,
thumbRectangle, thumbState);
TrackBarRenderer.DrawHorizontalTicks(e.Graphics,
ticksRectangle, numberTicks, EdgeStyle.Raised);
}
// Determine whether the user has clicked the track bar thumb.
protected override void OnMouseDown(MouseEventArgs e)
{
if (!TrackBarRenderer.IsSupported)
return;
if (this.thumbRectangle.Contains(e.Location))
{
thumbClicked = true;
thumbState = TrackBarThumbState.Pressed;
}
this.Invalidate();
}
// Redraw the track bar thumb if the user has moved it.
protected override void OnMouseUp(MouseEventArgs e)
{
if (!TrackBarRenderer.IsSupported)
return;
if (thumbClicked == true)
{
if (e.Location.X > trackRectangle.X &&
e.Location.X < (trackRectangle.X +
trackRectangle.Width - thumbRectangle.Width))
{
thumbClicked = false;
thumbState = TrackBarThumbState.Hot;
this.Invalidate();
}
thumbClicked = false;
}
}
// Track cursor movements.
protected override void OnMouseMove(MouseEventArgs e)
{
if (!TrackBarRenderer.IsSupported)
return;
// The user is moving the thumb.
if (thumbClicked == true)
{
// Track movements to the next tick to the right, if
// the cursor has moved halfway to the next tick.
if (currentTickPosition < numberTicks - 1 &&
e.Location.X > CurrentTickXCoordinate() +
(int)(tickSpace))
{
currentTickPosition++;
}
// Track movements to the next tick to the left, if
// cursor has moved halfway to the next tick.
else if (currentTickPosition > 0 &&
e.Location.X < CurrentTickXCoordinate() -
(int)(tickSpace / 2))
{
currentTickPosition--;
}
thumbRectangle.X = CurrentTickXCoordinate();
}
// The cursor is passing over the track.
else
{
thumbState = thumbRectangle.Contains(e.Location) ?
TrackBarThumbState.Hot : TrackBarThumbState.Normal;
}
Invalidate();
}
}
}
Imports System.Drawing
Imports System.Windows.Forms
Imports System.Windows.Forms.VisualStyles
Namespace TrackBarRendererSample
Class Form1
Inherits Form
Public Sub New()
Dim TrackBar1 As New CustomTrackBar(19, New Size(300, 50))
Me.Width = 500
Me.Controls.Add(TrackBar1)
End Sub
<STAThread()> _
Shared Sub Main()
' Note that the call to EnableVisualStyles below does
' not affect whether TrackBarRenderer.IsSupported is true;
' as long as visual styles are enabled by the operating system,
' IsSupported is true.
Application.EnableVisualStyles()
Application.Run(New Form1())
End Sub
End Class
Class CustomTrackBar
Inherits Control
Private numberTicks As Integer = 10
Private trackRectangle As New Rectangle()
Private ticksRectangle As New Rectangle()
Private thumbRectangle As New Rectangle()
Private currentTickPosition As Integer = 0
Private tickSpace As Single = 0
Private thumbClicked As Boolean = False
Private thumbState As TrackBarThumbState = TrackBarThumbState.Normal
Public Sub New(ByVal ticks As Integer, ByVal trackBarSize As Size)
With Me
.Location = New Point(10, 10)
.Size = trackBarSize
.numberTicks = ticks
.BackColor = Color.DarkCyan
.DoubleBuffered = True
End With
' Calculate the initial sizes of the bar,
' thumb and ticks.
SetupTrackBar()
End Sub
' Calculate the sizes of the bar, thumb, and ticks rectangle.
Private Sub SetupTrackBar()
If Not TrackBarRenderer.IsSupported Then
Return
End If
Using g As Graphics = Me.CreateGraphics()
' Calculate the size of the track bar.
trackRectangle.X = ClientRectangle.X + 2
trackRectangle.Y = ClientRectangle.Y + 28
trackRectangle.Width = ClientRectangle.Width - 4
trackRectangle.Height = 4
' Calculate the size of the rectangle in which to
' draw the ticks.
ticksRectangle.X = trackRectangle.X + 4
ticksRectangle.Y = trackRectangle.Y - 8
ticksRectangle.Width = trackRectangle.Width - 8
ticksRectangle.Height = 4
tickSpace = (CSng(ticksRectangle.Width) - 1) / _
(CSng(numberTicks) - 1)
' Calculate the size of the thumb.
thumbRectangle.Size = _
TrackBarRenderer.GetTopPointingThumbSize( _
g, TrackBarThumbState.Normal)
thumbRectangle.X = CurrentTickXCoordinate()
thumbRectangle.Y = trackRectangle.Y - 8
End Using
End Sub
Private Function CurrentTickXCoordinate() As Integer
If tickSpace = 0 Then
Return 0
Else
Return CInt(Math.Round(tickSpace)) * currentTickPosition
End If
End Function
' Draw the track bar.
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
If Not TrackBarRenderer.IsSupported Then
Me.Parent.Text = "CustomTrackBar Disabled"
Return
End If
Me.Parent.Text = "CustomTrackBar Enabled"
TrackBarRenderer.DrawHorizontalTrack(e.Graphics, _
trackRectangle)
TrackBarRenderer.DrawTopPointingThumb(e.Graphics, _
thumbRectangle, thumbState)
TrackBarRenderer.DrawHorizontalTicks(e.Graphics, _
ticksRectangle, numberTicks, EdgeStyle.Raised)
End Sub
' Determine whether the user has clicked the track bar thumb.
Protected Overrides Sub OnMouseDown(ByVal e As MouseEventArgs)
If Not TrackBarRenderer.IsSupported Then
Return
End If
If Me.thumbRectangle.Contains(e.Location) Then
thumbClicked = True
thumbState = TrackBarThumbState.Pressed
End If
Me.Invalidate()
End Sub
' Redraw the track bar thumb if the user has moved it.
Protected Overrides Sub OnMouseUp(ByVal e As MouseEventArgs)
If Not TrackBarRenderer.IsSupported Then
Return
End If
If thumbClicked = True Then
If e.Location.X > trackRectangle.X And _
e.Location.X < trackRectangle.X + _
trackRectangle.Width - thumbRectangle.Width Then
thumbClicked = False
thumbState = TrackBarThumbState.Hot
Me.Invalidate()
End If
thumbClicked = False
End If
End Sub
' Track cursor movements.
Protected Overrides Sub OnMouseMove(ByVal e As MouseEventArgs)
If Not TrackBarRenderer.IsSupported Then
Return
End If
' The user is moving the thumb.
If thumbClicked = True Then
' Track movements to the next tick to the right, if the
' cursor has moved halfway to the next tick.
If currentTickPosition < numberTicks - 1 And _
e.Location.X > CurrentTickXCoordinate() + _
CInt(tickSpace) Then
currentTickPosition += 1
' Track movements to the next tick to the left, if
' the cursor has moved halfway to the next tick.
Else
If currentTickPosition > 0 And _
e.Location.X < CurrentTickXCoordinate() - _
CInt(tickSpace / 2) Then
currentTickPosition -= 1
End If
End If
thumbRectangle.X = CurrentTickXCoordinate()
' The cursor is passing over the track.
Else
If thumbRectangle.Contains(e.Location) Then
thumbState = TrackBarThumbState.Hot
Else
thumbState = TrackBarThumbState.Normal
End If
End If
Invalidate()
End Sub
End Class
End Namespace
Remarks
The TrackBarRenderer class provides a set of static methods that can be used to render each part of a track bar control with the current visual style of the operating system. Rendering a control refers to drawing the user interface of a control. This is useful if you are drawing a custom control that should have the appearance of the current visual style.
If visual styles are enabled in the operating system and visual styles are applied to the client area of application windows, the methods in this class will draw the track bar with the current visual style. Otherwise, the methods in this class will throw an InvalidOperationException. To determine whether the members of this class can be used, you can check the value of the IsSupported property.
This class wraps the functionality of a System.Windows.Forms.VisualStyles.VisualStyleRenderer that is set to one of the elements exposed by the System.Windows.Forms.VisualStyles.VisualStyleElement.TrackBar class. For more information, see Rendering Controls with Visual Styles.
Properties
| IsSupported |
Gets a value indicating whether the TrackBarRenderer class can be used to draw a track bar with visual styles. |
Methods
| DrawBottomPointingThumb(Graphics, Rectangle, TrackBarThumbState) |
Draws a downward-pointing track bar slider (also known as the thumb) with visual styles. |
| DrawHorizontalThumb(Graphics, Rectangle, TrackBarThumbState) |
Draws a horizontal track bar slider (also known as the thumb) with visual styles. |
| DrawHorizontalTicks(Graphics, Rectangle, Int32, EdgeStyle) |
Draws the specified number of horizontal track bar ticks with visual styles. |
| DrawHorizontalTrack(Graphics, Rectangle) |
Draws the track for a horizontal track bar with visual styles. |
| DrawLeftPointingThumb(Graphics, Rectangle, TrackBarThumbState) |
Draws a left-pointing track bar slider (also known as the thumb) with visual styles. |
| DrawRightPointingThumb(Graphics, Rectangle, TrackBarThumbState) |
Draws a right-pointing track bar slider (also known as the thumb) with visual styles. |
| DrawTopPointingThumb(Graphics, Rectangle, TrackBarThumbState) |
Draws an upward-pointing track bar slider (also known as the thumb) with visual styles. |
| DrawVerticalThumb(Graphics, Rectangle, TrackBarThumbState) |
Draws a vertical track bar slider (also known as the thumb) with visual styles. |
| DrawVerticalTicks(Graphics, Rectangle, Int32, EdgeStyle) |
Draws the specified number of vertical track bar ticks with visual styles. |
| DrawVerticalTrack(Graphics, Rectangle) |
Draws the track for a vertical track bar with visual styles. |
| GetBottomPointingThumbSize(Graphics, TrackBarThumbState) |
Returns the size, in pixels, of the track bar slider (also known as the thumb) that points down. |
| GetLeftPointingThumbSize(Graphics, TrackBarThumbState) |
Returns the size, in pixels, of the track bar slider (also known as the thumb) that points to the left. |
| GetRightPointingThumbSize(Graphics, TrackBarThumbState) |
Returns the size, in pixels, of the track bar slider (also known as the thumb) that points to the right. |
| GetTopPointingThumbSize(Graphics, TrackBarThumbState) |
Returns the size, in pixels, of the track bar slider (also known as the thumb) that points up. |
Applies to
See also
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