ScrollBarRenderer Klasse
Definition
Wichtig
Einige Informationen beziehen sich auf Vorabversionen, die vor dem Release ggf. grundlegend überarbeitet werden. Microsoft übernimmt hinsichtlich der hier bereitgestellten Informationen keine Gewährleistungen, seien sie ausdrücklich oder konkludent.
Stellt Methoden bereit, mit denen ein Schiebeleisten-Steuerelement mit visuellen Stilen gerendert werden kann. Diese Klasse kann nicht vererbt werden.
public ref class ScrollBarRenderer sealedpublic ref class ScrollBarRenderer abstract sealedpublic sealed class ScrollBarRendererpublic static class ScrollBarRenderertype ScrollBarRenderer = classPublic NotInheritable Class ScrollBarRendererPublic Class ScrollBarRenderer- Vererbung
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ScrollBarRenderer
Beispiele
Im folgenden Codebeispiel wird veranschaulicht, wie Sie ein benutzerdefiniertes Steuerelement erstellen, das die ScrollBarRenderer Methoden verwendet, um eine Bildlaufleiste zu zeichnen, die auf Mausklicks reagiert.
#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 ScrollBarRendererSample
{
public ref class CustomScrollBar : public Control
{
private:
Rectangle clickedBarRectangle;
private:
Rectangle thumbRectangle;
private:
Rectangle leftArrowRectangle;
private:
Rectangle rightArrowRectangle;
private:
bool leftArrowClicked;
private:
bool rightArrowClicked;
private:
bool leftBarClicked;
private:
bool rightBarClicked;
private:
bool thumbClicked;
private:
ScrollBarState thumbState;
private:
ScrollBarArrowButtonState leftButtonState;
private:
ScrollBarArrowButtonState rightButtonState;
private:
int thumbWidth;
private:
int arrowWidth;
// The right limit of the thumb's right border.
private:
int thumbRightLimitRight;
// The right limit of the thumb's left border.
private:
int thumbRightLimitLeft;
// The left limit of thumb's left border.
private:
int thumbLeftLimit;
// The distance from the left edge of the thumb to the
// cursor tip.
private:
int thumbPosition;
// The distance from the left edge of the scroll bar track
// to the cursor tip.
private:
int trackPosition;
// This timer draws the moving thumb while the scroll arrows or
// track are pressed.
private:
Timer^ progressTimer;
public:
CustomScrollBar() : Control()
{
thumbState = ScrollBarState::Normal;
leftButtonState = ScrollBarArrowButtonState::LeftNormal;
rightButtonState = ScrollBarArrowButtonState::RightNormal;
// This control does not allow these widths to be altered.
thumbWidth = 15;
arrowWidth = 17;
progressTimer = gcnew Timer();
this->Location = Point(10, 10);
this->Width = 200;
this->Height = 20;
this->DoubleBuffered = true;
SetUpScrollBar();
progressTimer->Interval = 20;
progressTimer->Tick +=
gcnew EventHandler(this, &CustomScrollBar::progressTimer_Tick);
}
// Calculate the sizes of the scroll bar elements.
private:
void SetUpScrollBar()
{
clickedBarRectangle = ClientRectangle;
thumbRectangle = Rectangle(
ClientRectangle.X + ClientRectangle.Width / 2,
ClientRectangle.Y, thumbWidth,
ClientRectangle.Height);
leftArrowRectangle = Rectangle(
ClientRectangle.X, ClientRectangle.Y,
arrowWidth, ClientRectangle.Height);
rightArrowRectangle = Rectangle(
ClientRectangle.Right - arrowWidth,
ClientRectangle.Y, arrowWidth,
ClientRectangle.Height);
// Set the default starting thumb position.
thumbPosition = thumbWidth / 2;
// Set the right limit of the thumb's right border.
thumbRightLimitRight = ClientRectangle.Right - arrowWidth;
// Set the right limit of the thumb's left border.
thumbRightLimitLeft = thumbRightLimitRight - thumbWidth;
// Set the left limit of the thumb's left border.
thumbLeftLimit = ClientRectangle.X + arrowWidth;
}
// Draw the scroll bar in its normal state.
protected:
virtual void OnPaint(PaintEventArgs^ e) override
{
__super::OnPaint(e);
// Visual styles are not enabled.
if (!ScrollBarRenderer::IsSupported)
{
this->Parent->Text = "CustomScrollBar Disabled";
return;
}
this->Parent->Text = "CustomScrollBar Enabled";
// Draw the scroll bar track.
ScrollBarRenderer::DrawRightHorizontalTrack(e->Graphics,
ClientRectangle, ScrollBarState::Normal);
// Draw the thumb and thumb grip in the current state.
ScrollBarRenderer::DrawHorizontalThumb(e->Graphics,
thumbRectangle, thumbState);
ScrollBarRenderer::DrawHorizontalThumbGrip(e->Graphics,
thumbRectangle, thumbState);
// Draw the scroll arrows in the current state.
ScrollBarRenderer::DrawArrowButton(e->Graphics,
leftArrowRectangle, leftButtonState);
ScrollBarRenderer::DrawArrowButton(e->Graphics,
rightArrowRectangle, rightButtonState);
// Draw a highlighted rectangle in the left side of the scroll
// bar track if the user has clicked between the left arrow
// and thumb.
if (leftBarClicked)
{
clickedBarRectangle.X = thumbLeftLimit;
clickedBarRectangle.Width = thumbRectangle.X - thumbLeftLimit;
ScrollBarRenderer::DrawLeftHorizontalTrack(e->Graphics,
clickedBarRectangle, ScrollBarState::Pressed);
}
// Draw a highlighted rectangle in the right side of the scroll
// bar track if the user has clicked between the right arrow
// and thumb.
else if (rightBarClicked)
{
clickedBarRectangle.X =
thumbRectangle.X + thumbRectangle.Width;
clickedBarRectangle.Width =
thumbRightLimitRight - clickedBarRectangle.X;
ScrollBarRenderer::DrawRightHorizontalTrack(e->Graphics,
clickedBarRectangle, ScrollBarState::Pressed);
}
}
// Handle a mouse click in the scroll bar.
protected:
virtual void OnMouseDown(MouseEventArgs^ e) override
{
__super::OnMouseDown(e);
if (!ScrollBarRenderer::IsSupported)
{
return;
}
// When the thumb is clicked, update the distance from the left
// edge of the thumb to the cursor tip.
if (thumbRectangle.Contains(e->Location))
{
thumbClicked = true;
thumbPosition = e->Location.X - thumbRectangle.X;
thumbState = ScrollBarState::Pressed;
}
// When the left arrow is clicked, start the timer to scroll
// while the arrow is held down.
else if (leftArrowRectangle.Contains(e->Location))
{
leftArrowClicked = true;
leftButtonState = ScrollBarArrowButtonState::LeftPressed;
progressTimer->Start();
}
// When the right arrow is clicked, start the timer to scroll
// while the arrow is held down.
else if (rightArrowRectangle.Contains(e->Location))
{
rightArrowClicked = true;
rightButtonState = ScrollBarArrowButtonState::RightPressed;
progressTimer->Start();
}
// When the scroll bar is clicked, start the timer to move the
// thumb while the mouse is held down.
else
{
trackPosition = e->Location.X;
if (e->Location.X < this->thumbRectangle.X)
{
leftBarClicked = true;
}
else
{
rightBarClicked = true;
}
progressTimer->Start();
}
Invalidate();
}
// Draw the track.
protected:
virtual void OnMouseUp(MouseEventArgs^ e) override
{
__super::OnMouseUp(e);
if (!ScrollBarRenderer::IsSupported)
{
return;
}
// Update the thumb position, if the new location is within
// the bounds.
if (thumbClicked)
{
thumbClicked = false;
thumbState = ScrollBarState::Normal;
if (e->Location.X > (thumbLeftLimit + thumbPosition) &&
e->Location.X < (thumbRightLimitLeft + thumbPosition))
{
thumbRectangle.X = e->Location.X - thumbPosition;
}
}
// If one of the four thumb movement areas was clicked,
// stop the timer.
else if (leftArrowClicked)
{
leftArrowClicked = false;
leftButtonState = ScrollBarArrowButtonState::LeftNormal;
progressTimer->Stop();
}
else if (rightArrowClicked)
{
rightArrowClicked = false;
rightButtonState = ScrollBarArrowButtonState::RightNormal;
progressTimer->Stop();
}
else if (leftBarClicked)
{
leftBarClicked = false;
progressTimer->Stop();
}
else if (rightBarClicked)
{
rightBarClicked = false;
progressTimer->Stop();
}
Invalidate();
}
// Track mouse movements if the user clicks on the scroll bar thumb.
protected:
virtual void OnMouseMove(MouseEventArgs^ e) override
{
__super::OnMouseMove(e);
if (!ScrollBarRenderer::IsSupported)
{
return;
}
// Update the thumb position, if the new location is
// within the bounds.
if (thumbClicked)
{
// The thumb is all the way to the left.
if (e->Location.X <= (thumbLeftLimit + thumbPosition))
{
thumbRectangle.X = thumbLeftLimit;
}
// The thumb is all the way to the right.
else if (e->Location.X >=
(thumbRightLimitLeft + thumbPosition))
{
thumbRectangle.X = thumbRightLimitLeft;
}
// The thumb is between the ends of the track.
else
{
thumbRectangle.X = e->Location.X - thumbPosition;
}
Invalidate();
}
}
// Recalculate the sizes of the scroll bar elements.
protected:
virtual void OnSizeChanged(EventArgs^ e) override
{
__super::OnSizeChanged(e);
SetUpScrollBar();
}
// Handle the timer tick by updating the thumb position.
private:
void progressTimer_Tick(Object^ sender, EventArgs^ myEventArgs)
{
if (!ScrollBarRenderer::IsSupported)
{
return;
}
// If an arrow is clicked, move the thumb in small increments.
if (rightArrowClicked && thumbRectangle.X < thumbRightLimitLeft)
{
thumbRectangle.X++;
}
else if (leftArrowClicked && thumbRectangle.X > thumbLeftLimit)
{
thumbRectangle.X--;
}
// If the track bar to right of the thumb is clicked, move the
// thumb to the right in larger increments until the right edge
// of the thumb hits the cursor.
else if (rightBarClicked &&
thumbRectangle.X < thumbRightLimitLeft &&
thumbRectangle.X + thumbRectangle.Width < trackPosition)
{
thumbRectangle.X += 3;
}
// If the track bar to left of the thumb is clicked, move the
// thumb to the left in larger increments until the left edge
// of the thumb hits the cursor.
else if (leftBarClicked &&
thumbRectangle.X > thumbLeftLimit &&
thumbRectangle.X > trackPosition)
{
thumbRectangle.X -= 3;
}
Invalidate();
}
};
public ref class Form1 : public Form
{
public:
Form1() : Form()
{
this->Size = System::Drawing::Size(500, 500);
CustomScrollBar^ sampleCustomScrollBar = gcnew CustomScrollBar();
sampleCustomScrollBar->Location = Point(50, 100);
sampleCustomScrollBar->Size = System::Drawing::Size(200, 20);
Controls->Add(sampleCustomScrollBar);
}
};
}
[STAThread]
int main()
{
// The call to EnableVisualStyles below does not affect whether
// ScrollBarRenderer.IsSupported is true; as long as visual styles
// are enabled by the operating system, IsSupported is true.
Application::EnableVisualStyles();
Application::Run(gcnew ScrollBarRendererSample::Form1());
}
using System;
using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.VisualStyles;
namespace ScrollBarRendererSample
{
class Form1 : Form
{
public Form1()
: base()
{
this.Size = new Size(500, 500);
CustomScrollBar Bar1 = new CustomScrollBar();
Bar1.Location = new Point(50, 100);
Bar1.Size = new Size(200, 20);
Controls.Add(Bar1);
}
[STAThread]
static void Main()
{
// The call to EnableVisualStyles below does not affect whether
// ScrollBarRenderer.IsSupported is true; as long as visual styles
// are enabled by the operating system, IsSupported is true.
Application.EnableVisualStyles();
Application.Run(new Form1());
}
}
public class CustomScrollBar : Control
{
private Rectangle clickedBarRectangle;
private Rectangle thumbRectangle;
private Rectangle leftArrowRectangle;
private Rectangle rightArrowRectangle;
private bool leftArrowClicked = false;
private bool rightArrowClicked = false;
private bool leftBarClicked = false;
private bool rightBarClicked = false;
private bool thumbClicked = false;
private ScrollBarState thumbState = ScrollBarState.Normal;
private ScrollBarArrowButtonState leftButtonState =
ScrollBarArrowButtonState.LeftNormal;
private ScrollBarArrowButtonState rightButtonState =
ScrollBarArrowButtonState.RightNormal;
// This control does not allow these widths to be altered.
private int thumbWidth = 15;
private int arrowWidth = 17;
// Set the right limit of the thumb's right border.
private int thumbRightLimitRight = 0;
// Set the right limit of the thumb's left border.
private int thumbRightLimitLeft = 0;
// Set the left limit of thumb's left border.
private int thumbLeftLimit = 0;
// Set the distance from the left edge of the thumb to the
// cursor tip.
private int thumbPosition = 0;
// Set the distance from the left edge of the scroll bar track
// to the cursor tip.
private int trackPosition = 0;
// This timer draws the moving thumb while the scroll arrows or
// track are pressed.
private Timer progressTimer = new Timer();
public CustomScrollBar()
: base()
{
this.Location = new Point(10, 10);
this.Width = 200;
this.Height = 20;
this.DoubleBuffered = true;
SetUpScrollBar();
progressTimer.Interval = 20;
progressTimer.Tick += new EventHandler(progressTimer_Tick);
}
// Calculate the sizes of the scroll bar elements.
private void SetUpScrollBar()
{
clickedBarRectangle = ClientRectangle;
thumbRectangle = new Rectangle(
ClientRectangle.X + ClientRectangle.Width / 2,
ClientRectangle.Y, thumbWidth,
ClientRectangle.Height);
leftArrowRectangle = new Rectangle(
ClientRectangle.X, ClientRectangle.Y,
arrowWidth, ClientRectangle.Height);
rightArrowRectangle = new Rectangle(
ClientRectangle.Right - arrowWidth,
ClientRectangle.Y, arrowWidth,
ClientRectangle.Height);
// Set the default starting thumb position.
thumbPosition = thumbWidth / 2;
// Set the right limit of the thumb's right border.
thumbRightLimitRight = ClientRectangle.Right - arrowWidth;
// Set the right limit of the thumb's left border.
thumbRightLimitLeft = thumbRightLimitRight - thumbWidth;
// Set the left limit of the thumb's left border.
thumbLeftLimit = ClientRectangle.X + arrowWidth;
}
// Draw the scroll bar in its normal state.
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
// Visual styles are not enabled.
if (!ScrollBarRenderer.IsSupported)
{
this.Parent.Text = "CustomScrollBar Disabled";
return;
}
this.Parent.Text = "CustomScrollBar Enabled";
// Draw the scroll bar track.
ScrollBarRenderer.DrawRightHorizontalTrack(e.Graphics,
ClientRectangle, ScrollBarState.Normal);
// Draw the thumb and thumb grip in the current state.
ScrollBarRenderer.DrawHorizontalThumb(e.Graphics,
thumbRectangle, thumbState);
ScrollBarRenderer.DrawHorizontalThumbGrip(e.Graphics,
thumbRectangle, thumbState);
// Draw the scroll arrows in the current state.
ScrollBarRenderer.DrawArrowButton(e.Graphics,
leftArrowRectangle, leftButtonState);
ScrollBarRenderer.DrawArrowButton(e.Graphics,
rightArrowRectangle, rightButtonState);
// Draw a highlighted rectangle in the left side of the scroll
// bar track if the user has clicked between the left arrow
// and thumb.
if (leftBarClicked)
{
clickedBarRectangle.X = thumbLeftLimit;
clickedBarRectangle.Width = thumbRectangle.X - thumbLeftLimit;
ScrollBarRenderer.DrawLeftHorizontalTrack(e.Graphics,
clickedBarRectangle, ScrollBarState.Pressed);
}
// Draw a highlighted rectangle in the right side of the scroll
// bar track if the user has clicked between the right arrow
// and thumb.
else if (rightBarClicked)
{
clickedBarRectangle.X =
thumbRectangle.X + thumbRectangle.Width;
clickedBarRectangle.Width =
thumbRightLimitRight - clickedBarRectangle.X;
ScrollBarRenderer.DrawRightHorizontalTrack(e.Graphics,
clickedBarRectangle, ScrollBarState.Pressed);
}
}
// Handle a mouse click in the scroll bar.
protected override void OnMouseDown(MouseEventArgs e)
{
base.OnMouseDown(e);
if (!ScrollBarRenderer.IsSupported)
return;
// When the thumb is clicked, update the distance from the left
// edge of the thumb to the cursor tip.
if (thumbRectangle.Contains(e.Location))
{
thumbClicked = true;
thumbPosition = e.Location.X - thumbRectangle.X;
thumbState = ScrollBarState.Pressed;
}
// When the left arrow is clicked, start the timer to scroll
// while the arrow is held down.
else if (leftArrowRectangle.Contains(e.Location))
{
leftArrowClicked = true;
leftButtonState = ScrollBarArrowButtonState.LeftPressed;
progressTimer.Start();
}
// When the right arrow is clicked, start the timer to scroll
// while the arrow is held down.
else if (rightArrowRectangle.Contains(e.Location))
{
rightArrowClicked = true;
rightButtonState = ScrollBarArrowButtonState.RightPressed;
progressTimer.Start();
}
// When the scroll bar is clicked, start the timer to move the
// thumb while the mouse is held down.
else
{
trackPosition = e.Location.X;
if (e.Location.X < this.thumbRectangle.X)
{
leftBarClicked = true;
}
else
{
rightBarClicked = true;
}
progressTimer.Start();
}
Invalidate();
}
// Draw the track.
protected override void OnMouseUp(MouseEventArgs e)
{
base.OnMouseUp(e);
if (!ScrollBarRenderer.IsSupported)
return;
// Update the thumb position, if the new location is within
// the bounds.
if (thumbClicked)
{
thumbClicked = false;
thumbState = ScrollBarState.Normal;
if (e.Location.X > (thumbLeftLimit + thumbPosition) &&
e.Location.X < (thumbRightLimitLeft + thumbPosition))
{
thumbRectangle.X = e.Location.X - thumbPosition;
thumbClicked = false;
}
}
// If one of the four thumb movement areas was clicked,
// stop the timer.
else if (leftArrowClicked)
{
leftArrowClicked = false;
leftButtonState = ScrollBarArrowButtonState.LeftNormal;
progressTimer.Stop();
}
else if (rightArrowClicked)
{
rightArrowClicked = false;
rightButtonState = ScrollBarArrowButtonState.RightNormal;
progressTimer.Stop();
}
else if (leftBarClicked)
{
leftBarClicked = false;
progressTimer.Stop();
}
else if (rightBarClicked)
{
rightBarClicked = false;
progressTimer.Stop();
}
Invalidate();
}
// Track mouse movements if the user clicks on the scroll bar thumb.
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
if (!ScrollBarRenderer.IsSupported)
return;
// Update the thumb position, if the new location is
// within the bounds.
if (thumbClicked)
{
// The thumb is all the way to the left.
if (e.Location.X <= (thumbLeftLimit + thumbPosition))
{
thumbRectangle.X = thumbLeftLimit;
}
// The thumb is all the way to the right.
else if (e.Location.X >= (thumbRightLimitLeft + thumbPosition))
{
thumbRectangle.X = thumbRightLimitLeft;
}
// The thumb is between the ends of the track.
else
{
thumbRectangle.X = e.Location.X - thumbPosition;
}
Invalidate();
}
}
// Recalculate the sizes of the scroll bar elements.
protected override void OnSizeChanged(EventArgs e)
{
base.OnSizeChanged(e);
SetUpScrollBar();
}
// Handle the timer tick by updating the thumb position.
private void progressTimer_Tick(object sender, EventArgs myEventArgs)
{
if (!ScrollBarRenderer.IsSupported)
return;
// If an arrow is clicked, move the thumb in small increments.
if (rightArrowClicked && thumbRectangle.X < thumbRightLimitLeft)
{
thumbRectangle.X++;
}
else if (leftArrowClicked && thumbRectangle.X > thumbLeftLimit)
{
thumbRectangle.X--;
}
// If the track bar to right of the thumb is clicked, move the
// thumb to the right in larger increments until the right edge
// of the thumb hits the cursor.
else if (rightBarClicked &&
thumbRectangle.X < thumbRightLimitLeft &&
thumbRectangle.X + thumbRectangle.Width < trackPosition)
{
thumbRectangle.X += 3;
}
// If the track bar to left of the thumb is clicked, move the
// thumb to the left in larger increments until the left edge
// of the thumb hits the cursor.
else if (leftBarClicked &&
thumbRectangle.X > thumbLeftLimit &&
thumbRectangle.X > trackPosition)
{
thumbRectangle.X -= 3;
}
Invalidate();
}
}
}
Imports System.Drawing
Imports System.Windows.Forms
Imports System.Windows.Forms.VisualStyles
Namespace ScrollBarRendererSample
Class Form1
Inherits Form
Public Sub New()
Me.Size = New Size(500, 500)
Dim Bar1 As New CustomScrollBar()
Bar1.Location = New Point(50, 100)
Bar1.Size = New Size(200, 20)
Controls.Add(Bar1)
End Sub
<STAThread()> _
Shared Sub Main()
' The call to EnableVisualStyles below does not affect whether
' ScrollBarRenderer.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
Public Class CustomScrollBar
Inherits Control
Private clickedBarRectangle As Rectangle
Private thumbRectangle As Rectangle
Private leftArrowRectangle As Rectangle
Private rightArrowRectangle As Rectangle
Private leftArrowClicked As Boolean = False
Private rightArrowClicked As Boolean = False
Private leftBarClicked As Boolean = False
Private rightBarClicked As Boolean = False
Private thumbClicked As Boolean = False
Private thumbState As ScrollBarState = ScrollBarState.Normal
Private leftButtonState As ScrollBarArrowButtonState = _
ScrollBarArrowButtonState.LeftNormal
Private rightButtonState As ScrollBarArrowButtonState = _
ScrollBarArrowButtonState.RightNormal
' This control does not allow these widths to be altered.
Private thumbWidth As Integer = 15
Private arrowWidth As Integer = 17
' Set the right limit of the thumb's right border.
Private thumbRightLimitRight As Integer = 0
' Set the right limit of the thumb's left border.
Private thumbRightLimitLeft As Integer = 0
' Set the left limit of thumb's left border.
Private thumbLeftLimit As Integer = 0
' Set the distance from the left edge of the thumb to the
' cursor tip.
Private thumbPosition As Integer = 0
' Set the distance from the left edge of the scroll bar track to
' the cursor tip.
Private trackPosition As Integer = 0
' This timer draws the moving thumb while the scroll arrows or
' track are pressed.
Private WithEvents progressTimer As New Timer()
Public Sub New()
With Me
.Location = New Point(10, 10)
.Width = 200
.Height = 20
.DoubleBuffered = True
End With
SetUpScrollBar()
progressTimer.Interval = 20
End Sub
' Calculate the sizes of the scroll bar elements.
Private Sub SetUpScrollBar()
clickedBarRectangle = Me.ClientRectangle
thumbRectangle = New Rectangle(ClientRectangle.X + _
Me.ClientRectangle.Width / 2, Me.ClientRectangle.Y, _
thumbWidth, Me.ClientRectangle.Height)
leftArrowRectangle = New Rectangle(Me.ClientRectangle.X, _
Me.ClientRectangle.Y, arrowWidth, Me.ClientRectangle.Height)
rightArrowRectangle = New Rectangle(Me.ClientRectangle.Right - _
arrowWidth, Me.ClientRectangle.Y, arrowWidth, _
Me.ClientRectangle.Height)
' Set the default starting thumb position.
thumbPosition = thumbWidth / 2
' Set the right limit of the thumb's right border.
thumbRightLimitRight = Me.ClientRectangle.Right - arrowWidth
' Set the right limit of the thumb's left border.
thumbRightLimitLeft = thumbRightLimitRight - thumbWidth
' Set the left limit of the thumb's left border.
thumbLeftLimit = Me.ClientRectangle.X + arrowWidth
End Sub
' Draw the scroll bar in its normal state.
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
MyBase.OnPaint(e)
' Visual styles are not enabled.
If Not ScrollBarRenderer.IsSupported Then
Me.Parent.Text = "CustomScrollBar Disabled"
Return
End If
Me.Parent.Text = "CustomScrollBar Enabled"
' Draw the scroll bar track.
ScrollBarRenderer.DrawRightHorizontalTrack(e.Graphics, _
Me.ClientRectangle, ScrollBarState.Normal)
' Draw the thumb and thumb grip in the current state.
ScrollBarRenderer.DrawHorizontalThumb(e.Graphics, _
thumbRectangle, thumbState)
ScrollBarRenderer.DrawHorizontalThumbGrip(e.Graphics, _
thumbRectangle, thumbState)
' Draw the scroll arrows in the current state.
ScrollBarRenderer.DrawArrowButton(e.Graphics, _
leftArrowRectangle, leftButtonState)
ScrollBarRenderer.DrawArrowButton(e.Graphics, _
rightArrowRectangle, rightButtonState)
' Draw a highlighted rectangle in the left side of the scroll
' bar track if the user has clicked between the left arrow
' and thumb.
If leftBarClicked Then
clickedBarRectangle.X = thumbLeftLimit
clickedBarRectangle.Width = thumbRectangle.X - thumbLeftLimit
ScrollBarRenderer.DrawLeftHorizontalTrack(e.Graphics, _
clickedBarRectangle, ScrollBarState.Pressed)
' Draw a highlighted rectangle in the right side of the scroll
' bar track if the user has clicked between the right arrow
' and thumb.
ElseIf rightBarClicked Then
clickedBarRectangle.X = thumbRectangle.X + _
thumbRectangle.Width
clickedBarRectangle.Width = thumbRightLimitRight - _
clickedBarRectangle.X
ScrollBarRenderer.DrawRightHorizontalTrack(e.Graphics, _
clickedBarRectangle, ScrollBarState.Pressed)
End If
End Sub
' Handle a mouse click in the scroll bar.
Protected Overrides Sub OnMouseDown(ByVal e As MouseEventArgs)
MyBase.OnMouseDown(e)
If Not ScrollBarRenderer.IsSupported Then
Return
End If
' When the thumb is clicked, update the distance from the left
' edge of the thumb to the cursor tip.
If thumbRectangle.Contains(e.Location) Then
thumbClicked = True
thumbPosition = e.Location.X - thumbRectangle.X
thumbState = ScrollBarState.Pressed
' When the left arrow is clicked, start the timer to scroll
' while the arrow is held down.
ElseIf leftArrowRectangle.Contains(e.Location) Then
leftArrowClicked = True
leftButtonState = ScrollBarArrowButtonState.LeftPressed
progressTimer.Start()
' When the right arrow is clicked, start the timer to scroll
' while arrow is held down.
ElseIf rightArrowRectangle.Contains(e.Location) Then
rightArrowClicked = True
rightButtonState = ScrollBarArrowButtonState.RightPressed
progressTimer.Start()
' When the scroll bar is clicked, start the timer to move the
' thumb while the mouse is held down.
Else
trackPosition = e.Location.X
If e.Location.X < Me.thumbRectangle.X Then
leftBarClicked = True
Else
rightBarClicked = True
End If
progressTimer.Start()
End If
Invalidate()
End Sub
' Draw the track.
Protected Overrides Sub OnMouseUp(ByVal e As MouseEventArgs)
MyBase.OnMouseUp(e)
If Not ScrollBarRenderer.IsSupported Then
Return
End If
' Update the thumb position, if the new location is within
' the bounds.
If thumbClicked Then
thumbClicked = False
thumbState = ScrollBarState.Normal
If e.Location.X > thumbLeftLimit + thumbPosition And _
e.Location.X < thumbRightLimitLeft + thumbPosition Then
thumbRectangle.X = e.Location.X - thumbPosition
thumbClicked = False
End If
' If one of the four thumb movement areas was clicked,
' stop the timer.
ElseIf leftArrowClicked Then
leftArrowClicked = False
leftButtonState = ScrollBarArrowButtonState.LeftNormal
progressTimer.Stop()
ElseIf rightArrowClicked Then
rightArrowClicked = False
rightButtonState = ScrollBarArrowButtonState.RightNormal
progressTimer.Stop()
ElseIf leftBarClicked Then
leftBarClicked = False
progressTimer.Stop()
ElseIf rightBarClicked Then
rightBarClicked = False
progressTimer.Stop()
End If
Invalidate()
End Sub
' Track mouse movements if the user clicks on the scroll bar thumb.
Protected Overrides Sub OnMouseMove(ByVal e As MouseEventArgs)
MyBase.OnMouseMove(e)
If Not ScrollBarRenderer.IsSupported Then
Return
End If
' Update the thumb position, if the new location is
' within the bounds.
If thumbClicked Then
' The thumb is all the way to the left.
If e.Location.X <= thumbLeftLimit + thumbPosition Then
thumbRectangle.X = thumbLeftLimit
' The thumb is all the way to the right.
ElseIf e.Location.X >= thumbRightLimitLeft + thumbPosition Then
thumbRectangle.X = thumbRightLimitLeft
' The thumb is between the ends of the track.
Else
thumbRectangle.X = e.Location.X - thumbPosition
End If
Invalidate()
End If
End Sub
' Recalculate the sizes of the scroll bar elements.
Protected Overrides Sub OnSizeChanged(ByVal e As EventArgs)
MyBase.OnSizeChanged(e)
SetUpScrollBar()
End Sub
' Handle the timer tick by updating the thumb position.
Private Sub progressTimer_Tick(ByVal sender As Object, _
ByVal myEventArgs As EventArgs) Handles progressTimer.Tick
If Not ScrollBarRenderer.IsSupported Then
Return
End If
' If an arrow is clicked, move the thumb in small increments.
If rightArrowClicked And thumbRectangle.X < thumbRightLimitLeft Then
thumbRectangle.X += 1
ElseIf leftArrowClicked And thumbRectangle.X > thumbLeftLimit Then
thumbRectangle.X -= 1
' If the track bar to right of the thumb is clicked, move the
' thumb to the right in larger increments until the right edge
' of the thumb hits the cursor.
ElseIf rightBarClicked And thumbRectangle.X < thumbRightLimitLeft _
And thumbRectangle.X + thumbRectangle.Width < trackPosition Then
thumbRectangle.X += 3
' If the track bar to left of the thumb is clicked, move the
' thumb to the left in larger increments until the left edge
' of the thumb hits the cursor.
ElseIf leftBarClicked And thumbRectangle.X > thumbLeftLimit And _
thumbRectangle.X > trackPosition Then
thumbRectangle.X -= 3
End If
Invalidate()
End Sub
End Class
End Namespace
Hinweise
Die ScrollBarRenderer -Klasse stellt eine Reihe von static Methoden bereit, mit denen ein Bildlaufleistensteuerelement mit dem aktuellen visuellen Stil des Betriebssystems gerendert werden kann. Unter dem Rendern eine Steuerelements versteht man das Zeichnen der Benutzeroberfläche eines Steuerelements. Dies ist nützlich, wenn Sie ein benutzerdefiniertes Steuerelement zeichnen, das die Darstellung des aktuellen visuellen Stils aufweisen soll. Um eine Bildlaufleiste zu zeichnen, verwenden Sie eine Kombination der Methoden in dieser Klasse, um jeden Teil der Bildlaufleiste zu rendern.
Wenn visuelle Stile im Betriebssystem aktiviert sind und visuelle Stile auf den Clientbereich von Anwendungsfenstern angewendet werden, zeichnen die Methoden dieser Klasse die Bildlaufleiste mit dem aktuellen visuellen Stil. Andernfalls lösen die Methoden dieser Klasse einen aus InvalidOperationException. Um zu bestimmen, ob die Member dieser Klasse verwendet werden können, können Sie den Wert der IsSupported Eigenschaft überprüfen.
Diese Klasse umschließt die Funktionalität eines System.Windows.Forms.VisualStyles.VisualStyleRenderer , das auf eines der von der System.Windows.Forms.VisualStyles.VisualStyleElement.ScrollBar -Klasse verfügbar gemachten Elemente festgelegt ist. Weitere Informationen finden Sie unter Rendering von Steuerelementen mit visuellen Stilen.
Eigenschaften
| IsSupported |
Ruft einen Wert ab, der angibt, ob mithilfe der ScrollBarRenderer-Klasse eine Schiebeleiste mit visuellen Stilen gezeichnet werden kann. |
Methoden
| DrawArrowButton(Graphics, Rectangle, ScrollBarArrowButtonState) |
Zeichnet einen Bildlaufpfeil mit visuellen Stilen. |
| DrawHorizontalThumb(Graphics, Rectangle, ScrollBarState) |
Zeichnet ein horizontales Bildlauffeld (einen Ziehpunkt) mit visuellen Stilen. |
| DrawHorizontalThumbGrip(Graphics, Rectangle, ScrollBarState) |
Zeichnet einen Ziehpunkt auf einem horizontalen Bildlauffeld mit visuellen Stilen. |
| DrawLeftHorizontalTrack(Graphics, Rectangle, ScrollBarState) |
Zeichnet eine horizontale Schiebeleistenspur mit visuellen Stilen. |
| DrawLowerVerticalTrack(Graphics, Rectangle, ScrollBarState) |
Zeichnet eine vertikale Schiebeleistenspur mit visuellen Stilen. |
| DrawRightHorizontalTrack(Graphics, Rectangle, ScrollBarState) |
Zeichnet eine horizontale Schiebeleistenspur mit visuellen Stilen. |
| DrawSizeBox(Graphics, Rectangle, ScrollBarSizeBoxState) |
Zeichnet einen Schiebeleisten-Größenziehpunkt mit visuellen Stilen. |
| DrawUpperVerticalTrack(Graphics, Rectangle, ScrollBarState) |
Zeichnet eine vertikale Schiebeleistenspur mit visuellen Stilen. |
| DrawVerticalThumb(Graphics, Rectangle, ScrollBarState) |
Zeichnet ein vertikales Bildlauffeld (einen Ziehpunkt) mit visuellen Stilen. |
| DrawVerticalThumbGrip(Graphics, Rectangle, ScrollBarState) |
Zeichnet einen Ziehpunkt auf einem vertikalen Bildlauffeld mit visuellen Stilen. |
| GetSizeBoxSize(Graphics, ScrollBarState) |
Gibt die Größe des Größenziehpunkts zurück. |
| GetThumbGripSize(Graphics, ScrollBarState) |
Gibt die Größe des Bildlauffeld-Ziehpunkts zurück. |
Gilt für:
Weitere Informationen
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