TreeList.CustomDrawNodeCell Event

Provides the ability to perform custom painting of node cells.

Namespace: DevExpress.XtraTreeList

Assembly: DevExpress.XtraTreeList.v23.2.dll

NuGet Packages: DevExpress.Win.Navigation, DevExpress.Win.TreeList

Declaration

C#

[DXCategory("CustomDraw")]
public event CustomDrawNodeCellEventHandler CustomDrawNodeCell

VB.NET

<DXCategory("CustomDraw")>
Public Event CustomDrawNodeCell As CustomDrawNodeCellEventHandler

Event Data

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

Property	Description
Appearance	Gets the painted element’s appearance settings. Inherited from CustomDrawEventArgs.
Bounds	Gets the painted element’s bounding rectangle. Inherited from CustomDrawEventArgs.
Cache	Gets an object specifying the storage for the most used pens, fonts and brushes. Inherited from CustomDrawEventArgs.
CellText	Gets the painted cell’s display text.
CellValue	Gets the painted cell’s value.
Column	Gets the painted cell’s column.
EditPainter	Gets the editor’s painter object used to paint a cell.
EditViewInfo	Gets the editor’s view information.
Focused	Gets a value indicating whether the painted cell has focus.
Graphics	Gets an object used to paint. Inherited from CustomDrawEventArgs.
Handled	Gets or sets a value specifying whether an event was handled and that the default element painting is therefore not required. Inherited from CustomDrawEventArgs.
IsRightToLeft	Gets a value indicating whether the TreeList’s elements are aligned to support locales using right-to-left fonts. Inherited from CustomDrawEventArgs.
ObjectArgs	Gets an object containing information about the painted element. Inherited from CustomDrawEventArgs.
Painter	Gets the painter object that provides the default element’s painting mechanism. Inherited from CustomDrawEventArgs.

The event data class exposes the following methods:

Method	Description
DefaultDraw()	Performs default painting of an element. Inherited from CustomDrawEventArgs.
DrawHtml(HtmlTemplate, DxHtmlPainterContext, Action<DxHtmlPainterArgs>)	Paints the required HTML template inside an element that raised this event. The context parameter allows you to assign an object that transfers mouse events to template elements. Inherited from CustomDrawEventArgs.
DrawHtml(HtmlTemplate, Action<DxHtmlPainterArgs>)	Paints the required HTML template inside an element that raised this event. Inherited from CustomDrawEventArgs.

Remarks

The event parameter provides all the information necessary to paint a node cell. The e.Node and e.Column parameter properties allow you to identify the node and column to which a cell belongs.

See the Custom Draw Scenarios topic for information on using custom draw events.

Note

Custom drawing of any kind is ignored in the following instances:

• The user activates the cell’s editor.
• When printing/exporting the XtraTreeList. If it’s necessary to dynamically change cell styles in the print/export output of the Tree List control, handle the TreeList.NodeCellStyle event.

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.

Example

The following sample code handles the TreeList.CustomDrawNodeCell event. It is used to perform custom painting of node cells. All node cells are painted in the same manner.

The image below illustrates the result of executing the sample code.

C#

using System.Drawing;
using System.Drawing.Drawing2D;
using DevExpress.XtraTreeList;

private void treeList1_CustomDrawNodeCell(object sender, CustomDrawNodeCellEventArgs e) {
    // Create brushes for cells.
    Brush backBrush, foreBrush;
    if (e.Node != (sender as TreeList).FocusedNode)
    {
        backBrush = e.Cache.GetGradientBrush(e.Bounds, Color.PapayaWhip, Color.PeachPuff, LinearGradientMode.ForwardDiagonal);
        foreBrush = Brushes.Black;
    }
    else
    {
        backBrush = Brushes.DarkBlue;
        foreBrush = e.Cache.GetSolidBrush(Color.PeachPuff);
    }
    // Fill the background.
    e.Cache.FillRectangle(backBrush, e.Bounds);
    // Paint the node value.
    e.Cache.DrawString(e.CellText, e.Appearance.Font, foreBrush, e.Bounds,
      e.Appearance.GetStringFormat());

    // Prohibit default painting.
    e.Handled = true;
}

VB.NET

Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports DevExpress.XtraTreeList

Private Sub TreeList1_CustomDrawNodeCell(sender As Object, e As DevExpress.XtraTreeList.CustomDrawNodeCellEventArgs) Handles TreeList1.CustomDrawNodeCell
    ' Create brushes for cells.
    Dim BackBrush, ForeBrush As Brush
    If e.Node.Id <> sender.FocusedNode.Id Then
        BackBrush = e.Cache.GetGradientBrush(e.Bounds, Color.PapayaWhip,
                                             Color.PeachPuff, LinearGradientMode.ForwardDiagonal)
        ForeBrush = Brushes.Black
    Else
        BackBrush = Brushes.DarkBlue
        ForeBrush = Brushes.PeachPuff
    End If
    ' Fill the background.
    e.Cache.FillRectangle(BackBrush, e.Bounds)
    ' Paint the node value.
    e.Cache.DrawString(e.CellText, e.Appearance.Font, ForeBrush, e.Bounds,
                       e.Appearance.GetStringFormat())

    ' Prohibit default painting
    e.Handled = True
End Sub