NavBarControl.CustomDrawHint Event

Provides the capability to perform custom painting of hints in the VSToolBoxView paint style.

Namespace: DevExpress.XtraNavBar

Assembly: DevExpress.XtraNavBar.v20.1.dll

Declaration

public event NavBarCustomDrawHintEventHandler CustomDrawHint
Public Event CustomDrawHint As NavBarCustomDrawHintEventHandler

Event Data

The CustomDrawHint event's data class is NavBarCustomDrawHintEventArgs. The following properties provide information specific to this event:

Property Description
Appearance Gets the painted hint's appearance settings.
Bounds Gets the hint's bound rectangle.
Group Gets the group for which the hint is displayed. Inherited from NavBarCustomHintEventArgs.
Handled Gets or sets a value specifying whether the control should perform default hint painting.
Hint Gets the hint text.
HintInfo Gets an object providing information on the NavBarControl's element for which the hint event was fired. Inherited from NavBarCustomHintEventArgs.
Link Gets the link for which the hint is displayed. Inherited from NavBarCustomHintEventArgs.
PaintArgs Gets an object containing painting parameters.

Remarks

Write a CustomDrawHint event handler to perform custom painting of hints when the NavBarControl is painted using the VSToolBoxView style. In the VSToolBoxView style, hints are supported only for groups. In other paint styles, the CustomDrawHint event is not in effect. To custom paint hints in these styles, use the ToolTipController.CustomDraw event of a ToolTipController object (for instance, of the DefaultToolTipController object).

While handling the CustomDrawHint event, set the event's NavBarCustomDrawHintEventArgs.Handled parameter to true, to disable default painting. Other properties of the event parameter allow you to identify the group whose hint is painted, and provide all necessary information to paint.

IMPORTANT

Do not change cell values, modify the control's layout, or change the control's object model in the events used for custom control painting. Actions that update the layout can cause the control to malfunction.

Examples

The sample code below handles the NavBarControl.CustomDrawHint event to custom paint hints in the VSToolBoxView style. The NavBarControl.CalcHintSize event is handled to adjust the size of the hints in order to draw their outer borders.

The image below shows the result.

CustomDraw - Hints

using System.Drawing.Drawing2D;

private void navBarControl1_CalcHintSize(object sender, NavBarCalcHintSizeEventArgs e)
{
    // Enlarge the size of the hint to create space for drawing borders
    Size NewSize = e.Size;
    NewSize.Width += 18;
    NewSize.Height += 8;
    e.Size = new Size(NewSize.Width, NewSize.Height);
}

private void navBarControl1_CustomDrawHint(object sender, NavBarCustomDrawHintEventArgs e)
{
    // Obtain the object used to paint.
    Graphics gr = e.PaintArgs.Graphics;

    // Paint borders.
    LinearGradientBrush outerBrush = new LinearGradientBrush(e.Bounds, 
        Color.LightSkyBlue, Color.Blue, LinearGradientMode.Vertical);
    gr.FillRectangle(outerBrush, e.Bounds);
    outerBrush.Dispose();

    // Paint the background.
    // The background rectangle is reduced to make the borders visible.
    Rectangle innerRect = Rectangle.Inflate(e.Bounds, -3, -3);
    LinearGradientBrush innerBrush = new LinearGradientBrush(e.Bounds, 
        Color.Blue, Color.LightSkyBlue, LinearGradientMode.Vertical);
    gr.FillRectangle(innerBrush, innerRect);
    innerBrush.Dispose();

    // Format the output string.
    RectangleF textRect = new RectangleF(innerRect.Left, innerRect.Top, 
        innerRect.Width, innerRect.Height);
    StringFormat outStringFormat = new StringFormat();
    outStringFormat.Alignment = StringAlignment.Center;
    outStringFormat.LineAlignment = StringAlignment.Center;

    // Paint text.
    SolidBrush textBrush = new SolidBrush(Color.White);
    gr.DrawString(e.Hint, e.Appearance.Font, textBrush, textRect, outStringFormat);
    textBrush.Dispose();

    // Prohibit default hint painting         
    e.Handled = true;
}
See Also