TreeList.GetSelectImage Event

Allows you to assign select images to nodes.

Namespace: DevExpress.XtraTreeList

Assembly: DevExpress.XtraTreeList.v24.2.dll

Declaration

C#

public event GetSelectImageEventHandler GetSelectImage

VB.NET

Public Event GetSelectImage As GetSelectImageEventHandler

Event Data

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

Property	Description
FocusedNode	Gets or sets a value indicating whether a node is focused.
Node	Gets the current Tree List node. Inherited from NodeEventArgs.
NodeImageIndex	Gets or sets the index of the node’s image in a source image list. When handling the TreeList.GetStateImage event, the source of images is specified by the TreeList.StateImageList property. When handling the TreeList.GetSelectImage event, the source of images is specified by the TreeList.SelectImageList property. Inherited from GetStateImageEventArgs.

Remarks

Nodes can display the following icons:

• Select Image - two icons that automatically switch when a node gets / loses the focus.
• State Image - any custom icon.

Select Image

Specify image source

The TreeList.SelectImageList property specifies an ordered (indexed) collection that stores images. You can use the following image collections:

• ImageList — manages a collection of Image objects.
• ImageCollection — provides additional functionality compared to the ImageList class.
• SharedImageCollection — shares images between multiple controls and forms.
• SvgImageCollection — stores vector images.

Assign images to nodes

To specify the index of the image displayed in a particular node, use the following properties and events:

• the TreeList.ImageIndexFieldName property — specifies the name of the data field that contains image indexes. The property specifies the image index for both non-focused and focused states (you cannot use data source fields to specify two icons).

• the TreeListNode.ImageIndex and TreeListNode.SelectImageIndex properties — get or set the node’s image index in the non-focused and focused states, respectively. Images are automatically changed when a node gets / loses the focus.

  Note

  The SelectImageIndex and ImageIndex properties are not in effect if the TreeList obtains image indices from a data source field (ImageIndexFieldName).

  C#

  // Gets the select image index of the focused node.
  int selectImageIndex = treeList1.GetFocusedRowCellValue(treeList1.ImageIndexFieldName);
  

  VB.NET

  ' Gets the select image index of the focused node.
  Dim selectImageIndex As Integer = treeList1.GetFocusedRowCellValue(treeList1.ImageIndexFieldName)
  

• the TreeList.GetSelectImage event — fires before a node is displayed and allows you to specify (override) the image index for the processed node.

If the index is out of range, no image is displayed.

Respond to clicks

The TreeList.RowSelectImageClick event fires when a select image is clicked.

Example

This code below shows how to handle the TreeList.GetSelectImage event to assign select images to nodes depending on the focus state.

C#

using DevExpress.XtraTreeList;

treeList1.SelectImageList = imageCollection1;

private void treeList1_GetSelectImage(object sender, GetSelectImageEventArgs e) {
    if (e.FocusedNode)
        e.NodeImageIndex = 2;
    else
        e.NodeImageIndex = 0;
}

VB.NET

Imports DevExpress.XtraTreeList

treeList1.SelectImageList = imageCollection1

Private Sub TreeList1_GetSelectImage(ByVal sender As Object, _
ByVal e As GetSelectImageEventArgs) Handles TreeList1.GetSelectImage
    If e.FocusedNode Then
        e.NodeImageIndex = 2
    Else
        e.NodeImageIndex = 0
    End If
End Sub