ToolStripRenderer Class

Definition

Handles the painting functionality for ToolStrip objects.

public ref class ToolStripRenderer abstract
public abstract class ToolStripRenderer
type ToolStripRenderer = class
Public MustInherit Class ToolStripRenderer
Inheritance
ToolStripRenderer
Derived

Examples

The following code example demonstrates how to implement a custom ToolStripRenderer class. The GridStripRenderer class customizes three aspects of the GridStrip control's appearance: GridStrip border, ToolStripButton border, and ToolStripButton image. For a full code listing, see How to: Implement a Custom ToolStripRenderer.

// This class implements a custom ToolStripRenderer for the 
// GridStrip control. It customizes three aspects of the 
// GridStrip control's appearance: GridStrip border, 
// ToolStripButton border, and ToolStripButton image.
internal class GridStripRenderer : ToolStripRenderer
{   
    // The style of the empty cell's text.
    private static StringFormat style = new StringFormat();

    // The thickness (width or height) of a 
    // ToolStripButton control's border.
    static int borderThickness = 2;

    // The main bitmap that is the source for the 
    // subimagesthat are assigned to individual 
    // ToolStripButton controls.
    private Bitmap bmp = null;

    // The brush that paints the background of 
    // the GridStrip control.
    private Brush backgroundBrush = null;

    // This is the static constructor. It initializes the
    // StringFormat for drawing the text in the empty cell.
    static GridStripRenderer()
    {
        style.Alignment = StringAlignment.Center;
        style.LineAlignment = StringAlignment.Center;
    }

    // This method initializes the GridStripRenderer by
    // creating the image that is used as the source for
    // the individual button images.
    protected override void Initialize(ToolStrip ts)
    {
        base.Initialize(ts);

        this.InitializeBitmap(ts);
    }

    // This method initializes an individual ToolStripButton
    // control. It copies a subimage from the GridStripRenderer's
    // main image, according to the position and size of 
    // the ToolStripButton.
    protected override void InitializeItem(ToolStripItem item)
    {
        base.InitializeItem(item);

        GridStrip gs = item.Owner as GridStrip;

        // The empty cell does not receive a subimage.
        if ((item is ToolStripButton) &&
            (item != gs.EmptyCell))
        {
            // Copy the subimage from the appropriate 
            // part of the main image.
            Bitmap subImage = bmp.Clone(
                item.Bounds,
                PixelFormat.Undefined);

            // Assign the subimage to the ToolStripButton
            // control's Image property.
            item.Image = subImage;
        }
    }

    // This utility method creates the main image that
    // is the source for the subimages of the individual 
    // ToolStripButton controls.
    private void InitializeBitmap(ToolStrip toolStrip)
    {
        // Create the main bitmap, into which the image is drawn.
        this.bmp = new Bitmap(
            toolStrip.Size.Width,
            toolStrip.Size.Height);

        // Draw a fancy pattern. This could be any image or drawing.
        using (Graphics g = Graphics.FromImage(bmp))
        {
            // Draw smoothed lines.
            g.SmoothingMode = SmoothingMode.AntiAlias;
            
            // Draw the image. In this case, it is 
            // a number of concentric ellipses. 
            for (int i = 0; i < toolStrip.Size.Width; i += 8)
            {
                g.DrawEllipse(Pens.Blue, 0, 0, i, i);
            }
        }
    }

    // This method draws a border around the GridStrip control.
    protected override void OnRenderToolStripBorder(
        ToolStripRenderEventArgs e)
    {
        base.OnRenderToolStripBorder(e);

        ControlPaint.DrawFocusRectangle(
            e.Graphics,
            e.AffectedBounds,
            SystemColors.ControlDarkDark,
            SystemColors.ControlDarkDark);
    }

    // This method renders the GridStrip control's background.
    protected override void OnRenderToolStripBackground(
        ToolStripRenderEventArgs e)
    {
        base.OnRenderToolStripBackground(e);

        // This late initialization is a workaround. The gradient
        // depends on the bounds of the GridStrip control. The bounds 
        // are dependent on the layout engine, which hasn't fully
        // performed layout by the time the Initialize method runs.
        if (this.backgroundBrush == null)
        {
            this.backgroundBrush = new LinearGradientBrush(
               e.ToolStrip.ClientRectangle,
               SystemColors.ControlLightLight,
               SystemColors.ControlDark,
               90,
               true);
        }

        // Paint the GridStrip control's background.
        e.Graphics.FillRectangle(
            this.backgroundBrush, 
            e.AffectedBounds);
    }

    // This method draws a border around the button's image. If the background
    // to be rendered belongs to the empty cell, a string is drawn. Otherwise,
    // a border is drawn at the edges of the button.
    protected override void OnRenderButtonBackground(
        ToolStripItemRenderEventArgs e)
    {
        base.OnRenderButtonBackground(e);

        // Define some local variables for convenience.
        Graphics g = e.Graphics;
        GridStrip gs = e.ToolStrip as GridStrip;
        ToolStripButton gsb = e.Item as ToolStripButton;

        // Calculate the rectangle around which the border is painted.
        Rectangle imageRectangle = new Rectangle(
            borderThickness, 
            borderThickness, 
            e.Item.Width - 2 * borderThickness, 
            e.Item.Height - 2 * borderThickness);

        // If rendering the empty cell background, draw an 
        // explanatory string, centered in the ToolStripButton.
        if (gsb == gs.EmptyCell)
        {
            e.Graphics.DrawString(
                "Drag to here",
                gsb.Font, 
                SystemBrushes.ControlDarkDark,
                imageRectangle, style);
        }
        else
        {
            // If the button can be a drag source, paint its border red.
            // otherwise, paint its border a dark color.
            Brush b = gs.IsValidDragSource(gsb) ? b = 
                Brushes.Red : SystemBrushes.ControlDarkDark;

            // Draw the top segment of the border.
            Rectangle borderSegment = new Rectangle(
                0, 
                0, 
                e.Item.Width, 
                imageRectangle.Top);
            g.FillRectangle(b, borderSegment);

            // Draw the right segment.
            borderSegment = new Rectangle(
                imageRectangle.Right,
                0,
                e.Item.Bounds.Right - imageRectangle.Right,
                imageRectangle.Bottom);
            g.FillRectangle(b, borderSegment);

            // Draw the left segment.
            borderSegment = new Rectangle(
                0,
                0,
                imageRectangle.Left,
                e.Item.Height);
            g.FillRectangle(b, borderSegment);

            // Draw the bottom segment.
            borderSegment = new Rectangle(
                0,
                imageRectangle.Bottom,
                e.Item.Width,
                e.Item.Bounds.Bottom - imageRectangle.Bottom);
            g.FillRectangle(b, borderSegment);
        }
    }
}
' This class implements a custom ToolStripRenderer for the 
' GridStrip control. It customizes three aspects of the 
' GridStrip control's appearance: GridStrip border, 
' ToolStripButton border, and ToolStripButton image.
Friend Class GridStripRenderer
     Inherits ToolStripRenderer

   ' The style of the empty cell's text.
   Private Shared style As New StringFormat()
   
   ' The thickness (width or height) of a 
   ' ToolStripButton control's border.
   Private Shared borderThickness As Integer = 2
   
   ' The main bitmap that is the source for the 
   ' subimagesthat are assigned to individual 
   ' ToolStripButton controls.
   Private bmp As Bitmap = Nothing
   
   ' The brush that paints the background of 
   ' the GridStrip control.
   Private backgroundBrush As Brush = Nothing
   
   
   ' This is the static constructor. It initializes the
   ' StringFormat for drawing the text in the empty cell.
   Shared Sub New()
      style.Alignment = StringAlignment.Center
      style.LineAlignment = StringAlignment.Center
   End Sub 
   
   ' This method initializes the GridStripRenderer by
   ' creating the image that is used as the source for
   ' the individual button images.
   Protected Overrides Sub Initialize(ts As ToolStrip)
      MyBase.Initialize(ts)
      
      Me.InitializeBitmap(ts)
     End Sub

   ' This method initializes an individual ToolStripButton
   ' control. It copies a subimage from the GridStripRenderer's
   ' main image, according to the position and size of 
   ' the ToolStripButton.
   Protected Overrides Sub InitializeItem(item As ToolStripItem)
      MyBase.InitializeItem(item)
      
         Dim gs As GridStrip = item.Owner
      
      ' The empty cell does not receive a subimage.
         If ((TypeOf (item) Is ToolStripButton) And _
              (item IsNot gs.EmptyCell)) Then
             ' Copy the subimage from the appropriate 
             ' part of the main image.
             Dim subImage As Bitmap = bmp.Clone(item.Bounds, PixelFormat.Undefined)

             ' Assign the subimage to the ToolStripButton
             ' control's Image property.
             item.Image = subImage
         End If
   End Sub 

   ' This utility method creates the main image that
   ' is the source for the subimages of the individual 
   ' ToolStripButton controls.
   Private Sub InitializeBitmap(toolStrip As ToolStrip)
      ' Create the main bitmap, into which the image is drawn.
      Me.bmp = New Bitmap(toolStrip.Size.Width, toolStrip.Size.Height)
      
      ' Draw a fancy pattern. This could be any image or drawing.
      Dim g As Graphics = Graphics.FromImage(bmp)
      Try
         ' Draw smoothed lines.
         g.SmoothingMode = SmoothingMode.AntiAlias
         
         ' Draw the image. In this case, it is 
         ' a number of concentric ellipses. 
         Dim i As Integer
         For i = 0 To toolStrip.Size.Width - 8 Step 8
            g.DrawEllipse(Pens.Blue, 0, 0, i, i)
         Next i
      Finally
         g.Dispose()
      End Try
   End Sub 
   
   ' This method draws a border around the GridStrip control.
   Protected Overrides Sub OnRenderToolStripBorder(e As ToolStripRenderEventArgs)
      MyBase.OnRenderToolStripBorder(e)
      
      ControlPaint.DrawFocusRectangle(e.Graphics, e.AffectedBounds, SystemColors.ControlDarkDark, SystemColors.ControlDarkDark)
   End Sub 

   ' This method renders the GridStrip control's background.
   Protected Overrides Sub OnRenderToolStripBackground(e As ToolStripRenderEventArgs)
      MyBase.OnRenderToolStripBackground(e)
      
      ' This late initialization is a workaround. The gradient
      ' depends on the bounds of the GridStrip control. The bounds 
      ' are dependent on the layout engine, which hasn't fully
      ' performed layout by the time the Initialize method runs.
      If Me.backgroundBrush Is Nothing Then
         Me.backgroundBrush = New LinearGradientBrush(e.ToolStrip.ClientRectangle, SystemColors.ControlLightLight, SystemColors.ControlDark, 90, True)
      End If
      
      ' Paint the GridStrip control's background.
      e.Graphics.FillRectangle(Me.backgroundBrush, e.AffectedBounds)
     End Sub

   ' This method draws a border around the button's image. If the background
   ' to be rendered belongs to the empty cell, a string is drawn. Otherwise,
   ' a border is drawn at the edges of the button.
   Protected Overrides Sub OnRenderButtonBackground(e As ToolStripItemRenderEventArgs)
      MyBase.OnRenderButtonBackground(e)
      
      ' Define some local variables for convenience.
      Dim g As Graphics = e.Graphics
      Dim gs As GridStrip = e.ToolStrip 
      Dim gsb As ToolStripButton = e.Item 
      
      ' Calculate the rectangle around which the border is painted.
      Dim imageRectangle As New Rectangle(borderThickness, borderThickness, e.Item.Width - 2 * borderThickness, e.Item.Height - 2 * borderThickness)
      
      ' If rendering the empty cell background, draw an 
      ' explanatory string, centered in the ToolStripButton.
         If gsb Is gs.EmptyCell Then
             e.Graphics.DrawString("Drag to here", gsb.Font, SystemBrushes.ControlDarkDark, imageRectangle, style)
         Else
             ' If the button can be a drag source, paint its border red.
             ' otherwise, paint its border a dark color.
             Dim b As Brush = IIf(gs.IsValidDragSource(gsb), Brushes.Red, SystemBrushes.ControlDarkDark)

             ' Draw the top segment of the border.
             Dim borderSegment As New Rectangle(0, 0, e.Item.Width, imageRectangle.Top)
             g.FillRectangle(b, borderSegment)

             ' Draw the right segment.
             borderSegment = New Rectangle(imageRectangle.Right, 0, e.Item.Bounds.Right - imageRectangle.Right, imageRectangle.Bottom)
             g.FillRectangle(b, borderSegment)

             ' Draw the left segment.
             borderSegment = New Rectangle(0, 0, imageRectangle.Left, e.Item.Height)
             g.FillRectangle(b, borderSegment)

             ' Draw the bottom segment.
             borderSegment = New Rectangle(0, imageRectangle.Bottom, e.Item.Width, e.Item.Bounds.Bottom - imageRectangle.Bottom)
             g.FillRectangle(b, borderSegment)
         End If
     End Sub
 End Class

Remarks

Use the ToolStripRenderer class to apply a particular style or theme to a ToolStrip. Rather than custom painting a ToolStrip and the ToolStripItem objects it contains, you set the ToolStrip.Renderer property to an object that inherits from ToolStripRenderer. The painting specified by the ToolStripRenderer is applied to the ToolStrip, as well as the items it contains.

You can do custom painting in ToolStrip controls in several ways. As with other Windows Forms controls, the ToolStrip and ToolStripItem both have overridable OnPaint methods and Paint events. As with regular painting, the coordinate system is relative to the client area of the control; that is, the upper left-hand corner of the control is 0, 0. The Paint event and OnPaint method for a ToolStripItem behave like other control paint events.

The ToolStripRenderer class has overridable methods for painting the background, item background, item image, item arrow, item text, and border of the ToolStrip. The event arguments for these methods expose several properties such as rectangles, colors, and text formats that you can adjust as desired.

To adjust just a few aspects of how an item is painted, you typically override the ToolStripRenderer.

If you are writing a new item and want to control all aspects of the painting, override the OnPaint method. From within OnPaint, you can use methods from the ToolStripRenderer.

By default, the ToolStrip is double buffered, taking advantage of the OptimizedDoubleBuffer setting.

Constructors

ToolStripRenderer()

Initializes a new instance of the ToolStripRenderer class.

Fields

Offset2X

Gets or sets the offset multiplier for twice the offset along the x-axis.

Offset2Y

Gets or sets the offset multiplier for twice the offset along the y axis.

Methods

CreateDisabledImage(Image)

Creates a gray-scale copy of a given image.

DrawArrow(ToolStripArrowRenderEventArgs)

Draws an arrow on a ToolStripItem.

DrawButtonBackground(ToolStripItemRenderEventArgs)

Draws the background for a ToolStripButton.

DrawDropDownButtonBackground(ToolStripItemRenderEventArgs)

Draws the background for a ToolStripDropDownButton.

DrawGrip(ToolStripGripRenderEventArgs)

Draws a move handle on a ToolStrip.

DrawImageMargin(ToolStripRenderEventArgs)

Draws the space around an image on a ToolStrip.

DrawItemBackground(ToolStripItemRenderEventArgs)

Draws the background for a ToolStripItem.

DrawItemCheck(ToolStripItemImageRenderEventArgs)

Draws an image on a ToolStripItem that indicates the item is in a selected state.

DrawItemImage(ToolStripItemImageRenderEventArgs)

Draws an image on a ToolStripItem.

DrawItemText(ToolStripItemTextRenderEventArgs)

Draws text on a ToolStripItem.

DrawLabelBackground(ToolStripItemRenderEventArgs)

Draws the background for a ToolStripLabel.

DrawMenuItemBackground(ToolStripItemRenderEventArgs)

Draws the background for a ToolStripMenuItem.

DrawOverflowButtonBackground(ToolStripItemRenderEventArgs)

Draws the background for an overflow button.

DrawSeparator(ToolStripSeparatorRenderEventArgs)

Draws a ToolStripSeparator.

DrawSplitButton(ToolStripItemRenderEventArgs)

Draws a ToolStripSplitButton.

DrawStatusStripSizingGrip(ToolStripRenderEventArgs)

Draws a sizing grip.

DrawToolStripBackground(ToolStripRenderEventArgs)

Draws the background for a ToolStrip.

DrawToolStripBorder(ToolStripRenderEventArgs)

Draws the border for a ToolStrip.

DrawToolStripContentPanelBackground(ToolStripContentPanelRenderEventArgs)

Draws the background of the ToolStripContentPanel.

DrawToolStripPanelBackground(ToolStripPanelRenderEventArgs)

Draws the background of the ToolStripPanel.

DrawToolStripStatusLabelBackground(ToolStripItemRenderEventArgs)

Draws the background of the ToolStripStatusLabel.

Equals(Object)

Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode()

Serves as the default hash function.

(Inherited from Object)
GetType()

Gets the Type of the current instance.

(Inherited from Object)
Initialize(ToolStrip)

When overridden in a derived class, provides for custom initialization of the given ToolStrip.

InitializeContentPanel(ToolStripContentPanel)

Initializes the specified ToolStripContentPanel.

InitializeItem(ToolStripItem)

When overridden in a derived class, provides for custom initialization of the given ToolStripItem.

InitializePanel(ToolStripPanel)

Initializes the specified ToolStripPanel.

MemberwiseClone()

Creates a shallow copy of the current Object.

(Inherited from Object)
OnRenderArrow(ToolStripArrowRenderEventArgs)

Raises the RenderArrow event.

OnRenderButtonBackground(ToolStripItemRenderEventArgs)

Raises the RenderButtonBackground event.

OnRenderDropDownButtonBackground(ToolStripItemRenderEventArgs)

Raises the RenderDropDownButtonBackground event.

OnRenderGrip(ToolStripGripRenderEventArgs)

Raises the RenderGrip event.

OnRenderImageMargin(ToolStripRenderEventArgs)

Draws the item background.

OnRenderItemBackground(ToolStripItemRenderEventArgs)

Raises the OnRenderItemBackground(ToolStripItemRenderEventArgs) event.

OnRenderItemCheck(ToolStripItemImageRenderEventArgs)

Raises the RenderItemCheck event.

OnRenderItemImage(ToolStripItemImageRenderEventArgs)

Raises the RenderItemImage event.

OnRenderItemText(ToolStripItemTextRenderEventArgs)

Raises the RenderItemText event.

OnRenderLabelBackground(ToolStripItemRenderEventArgs)

Raises the RenderLabelBackground event.

OnRenderMenuItemBackground(ToolStripItemRenderEventArgs)

Raises the RenderMenuItemBackground event.

OnRenderOverflowButtonBackground(ToolStripItemRenderEventArgs)

Raises the RenderOverflowButtonBackground event.

OnRenderSeparator(ToolStripSeparatorRenderEventArgs)

Raises the RenderSeparator event.

OnRenderSplitButtonBackground(ToolStripItemRenderEventArgs)

Raises the OnRenderSplitButtonBackground(ToolStripItemRenderEventArgs) event.

OnRenderStatusStripSizingGrip(ToolStripRenderEventArgs)

Raises the RenderStatusStripSizingGrip event.

OnRenderToolStripBackground(ToolStripRenderEventArgs)

Raises the RenderToolStripBackground event.

OnRenderToolStripBorder(ToolStripRenderEventArgs)

Raises the RenderToolStripBorder event.

OnRenderToolStripContentPanelBackground(ToolStripContentPanelRenderEventArgs)

Raises the RenderToolStripContentPanelBackground event.

OnRenderToolStripPanelBackground(ToolStripPanelRenderEventArgs)

Raises the RenderToolStripPanelBackground event.

OnRenderToolStripStatusLabelBackground(ToolStripItemRenderEventArgs)

Raises the RenderToolStripStatusLabelBackground event.

ScaleArrowOffsetsIfNeeded()

Applies the Offset2X and Offset2Y values to scaling the arrow icon, if scaling is required based on the DPI settings of the computer.

ScaleArrowOffsetsIfNeeded(Int32)

Applies the Offset2X and Offset2Y values to scaling the arrow icon based on the specified DPI value.

ToString()

Returns a string that represents the current object.

(Inherited from Object)

Events

RenderArrow

Occurs when an arrow on a ToolStripItem is rendered.

RenderButtonBackground

Occurs when the background for a ToolStripButton is rendered.

RenderDropDownButtonBackground

Occurs when the background for a ToolStripDropDownButton is rendered.

RenderGrip

Occurs when the move handle for a ToolStrip is rendered.

RenderImageMargin

Draws the margin between an image and its container.

RenderItemBackground

Occurs when the background for a ToolStripItem is rendered.

RenderItemCheck

Occurs when the image for a selected ToolStripItem is rendered.

RenderItemImage

Occurs when the image for a ToolStripItem is rendered.

RenderItemText

Occurs when the text for a ToolStripItem is rendered.

RenderLabelBackground

Occurs when the background for a ToolStripLabel is rendered.

RenderMenuItemBackground

Occurs when the background for a ToolStripMenuItem is rendered.

RenderOverflowButtonBackground

Occurs when the background for an overflow button is rendered.

RenderSeparator

Occurs when a ToolStripSeparator is rendered.

RenderSplitButtonBackground

Occurs when the background for a ToolStripSplitButton is rendered.

RenderStatusStripSizingGrip

Occurs when the display style changes.

RenderToolStripBackground

Occurs when the background for a ToolStrip is rendered.

RenderToolStripBorder

Occurs when the border for a ToolStrip is rendered.

RenderToolStripContentPanelBackground

Draws the background of a ToolStripContentPanel.

RenderToolStripPanelBackground

Draws the background of a ToolStripPanel.

RenderToolStripStatusLabelBackground

Draws the background of a ToolStripStatusLabel.

Applies to

See also