TreeList.CustomDrawEmptyArea Event

Enables you to custom paint a Tree List’s empty area.

Namespace: DevExpress.XtraTreeList

Assembly: DevExpress.XtraTreeList.v19.1.dll

Declaration

C#

[DXCategory("CustomDraw")]
public event CustomDrawEmptyAreaEventHandler CustomDrawEmptyArea

VB.NET

<DXCategory("CustomDraw")>
Public Event CustomDrawEmptyArea As CustomDrawEmptyAreaEventHandler

Event Data

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

Property	Description
Appearance	Gets the painted element’s appearance settings. Inherited from CustomDrawEventArgs.
BehindColumn	Gets the blank column’s bounding rectangle.
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.
EmptyAreaRegion	Gets the region which is occupied by the empty area.
EmptyRectangles	Gets the array of rectangles that specify the empty area.
EmptyRows	Gets the bounding rectangle occupied by the empty rows.
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.

Remarks

Handle the CustomDrawEmptyArea event to custom paint the control’s empty area(the area where Tree List nodes are going to be displayed).

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

Important

Never change cell values or modify the control’s layout on this event, or any other event designed to tune the control’s appearance. Any action that causes a layout update can cause the control to malfunction.

Example

The following code handles the TreeList.CustomDrawEmptyArea event to manually paint the control’s empty area when no nodes are displayed.

The image below shows the result.

C#

using DevExpress.XtraTreeList;

private void treeList1_CustomDrawEmptyArea(object sender, CustomDrawEmptyAreaEventArgs e) {
    if (treeList1.Nodes.Count > 1) return;
    string s = "No Records Available";
    e.Appearance.FontStyleDelta = FontStyle.Bold;
    e.Appearance.FontSizeDelta = 2;
    e.Cache.DrawString(s, e.Appearance.Font, e.Cache.GetSolidBrush(Color.Black), e.Bounds);
    e.Handled = true;
}

VB.NET

Imports DevExpress.XtraTreeList

Private Sub TreeList1_CustomDrawEmptyArea(sender As Object, e As DevExpress.XtraTreeList.CustomDrawEmptyAreaEventArgs) Handles TreeList1.CustomDrawEmptyArea
    If TreeList1.Nodes.Count > 1 Then Return
    Dim s As String = "No Records Available"
    e.Appearance.FontStyleDelta = FontStyle.Bold
    e.Appearance.FontSizeDelta = 2
    e.Cache.DrawString(s, e.Appearance.Font, e.Cache.GetSolidBrush(Color.Black), e.Bounds)
    e.Handled = True
End Sub