TreeList.CustomDrawFooterCell Event

Gives you the ability to perform custom painting of column footer cells.

Namespace: DevExpress.XtraTreeList

Assembly: DevExpress.XtraTreeList.v23.2.dll

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

Declaration

C#

[DXCategory("CustomDraw")]
public event CustomDrawFooterCellEventHandler CustomDrawFooterCell

VB.NET

<DXCategory("CustomDraw")>
Public Event CustomDrawFooterCell As CustomDrawFooterCellEventHandler

Event Data

The CustomDrawFooterCell event's data class is CustomDrawFooterCellEventArgs. 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.
CellInfo	Gets an object containing information about the painted element.
Column	Gets a column whose footer cell is painted.
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.
ItemType	Gets the type of summary whose value is displayed within the painted cell.
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.
Text	Gets or sets the text intended to be displayed within the painted footer cell.

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

By default, column footer cells display summary values. Handle the CustomDrawFooterCell event to custom paint footer cells. Use the CustomDrawFooterCellEventArgs.Text property of the event’s parameter to determine the painted cell’s value. Other properties of the event’s parameter provide you all the information necessary to paint a cell.

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

The footer panel can be custom painted by handling the TreeList.CustomDrawFooter 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.CustomDrawFooter and TreeList.CustomDrawFooterCell events. The TreeList.CustomDrawFooter event handler is used to perform custom painting of the footer panel. Column footer cells containing text are painted by handling the TreeList.CustomDrawFooterCell event.

The image below displays the result of sample code execution.

C#

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

private void treeList1_CustomDrawFooter(object sender, CustomDrawEventArgs e) {
    // painting the footer panel's background with a linear gradient brush
    Brush backBrush = e.Cache.GetGradientBrush(e.Bounds, Color.LightSkyBlue, 
        Color.Blue, LinearGradientMode.Vertical);
    e.Cache.FillRectangle(backBrush, e.Bounds);
    // painting borders
    e.Cache.DrawRectangle(e.Cache.GetPen(Color.LightGray), e.Bounds);

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

private void treeList1_CustomDrawFooterCell(object sender, CustomDrawFooterCellEventArgs e) {
    // cells containing no text are not painted
    if (e.Text == string.Empty) return;

    // filling cells background with a linear gradient brush
    Brush backBrush = e.Cache.GetGradientBrush(e.Bounds, Color.Orange,
      Color.PeachPuff, LinearGradientMode.Vertical);
    e.Cache.FillRectangle(backBrush, e.Bounds);
    // painting borders
    e.Cache.DrawRectangle(e.Cache.GetPen(Color.LightGray), e.Bounds);
    // painting the footer cell value
    e.Cache.DrawString(e.Text, e.Appearance.Font, e.Cache.GetSolidBrush(Color.Blue),
      e.Bounds, e.Appearance.GetStringFormat());

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

VB.NET

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

Private Sub TreeList1_CustomDrawFooter(sender As Object, e As DevExpress.XtraTreeList.CustomDrawEventArgs) Handles TreeList1.CustomDrawFooter
    ' painting the footer panel's background with a linear gradient brush
    Dim BackBrush = e.Cache.GetGradientBrush(e.Bounds, Color.LightSkyBlue,
                                             Color.Blue, LinearGradientMode.Vertical)
    e.Cache.FillRectangle(BackBrush, e.Bounds)
    ' painting borders
    e.Cache.DrawRectangle(e.Cache.GetPen(Color.LightGray), e.Bounds)

    ' prohibiting default painting
    e.Handled = True

End Sub

Private Sub TreeList1_CustomDrawFooterCell(sender As Object, e As DevExpress.XtraTreeList.CustomDrawFooterCellEventArgs) Handles TreeList1.CustomDrawFooterCell
    ' cells containing no text are not painted
    If e.Text = String.Empty Then Exit Sub
    ' filling cells background with a linear gradient brush
    Dim BackBrush = e.Cache.GetGradientBrush(e.Bounds, Color.Orange,
                                             Color.PeachPuff, LinearGradientMode.Vertical)
    e.Cache.FillRectangle(BackBrush, e.Bounds)
    ' painting borders
    e.Cache.DrawRectangle(e.Cache.GetPen(Color.LightGray), e.Bounds)
    ' painting the footer cell value
    e.Cache.DrawString(e.Text, e.Appearance.Font, e.Cache.GetSolidBrush(Color.Blue),
                       e.Bounds, e.Appearance.GetStringFormat())
    ' prohibiting default painting
    e.Handled = True

End Sub