TreeList.ImageIndexFieldName Property

Gets or sets the name of the field whose values represent select image indexes for corresponding nodes.

Namespace: DevExpress.XtraTreeList

Assembly: DevExpress.XtraTreeList.v24.2.dll

Declaration

C#

[DefaultValue("ImageIndex")]
[XtraSerializableProperty]
public string ImageIndexFieldName { get; set; }

VB.NET

<DefaultValue("ImageIndex")>
<XtraSerializableProperty>
Public Property ImageIndexFieldName As String

Property Value

Type	Default	Description
String	"ImageIndex"	A string value that specifies the name of the data field that stores image indexes.

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

The code below shows how to assign select and state images to nodes.

C#

using DevExpress.XtraTreeList.Nodes;

// Data source for select (left) images.
treeList1.SelectImageList = imageCollection1;
// Use the data source to assign select images to nodes.
// Data source fields do NOT allow you to specify
// two images that depend on the focus.
// This property has priority over the node's
// ImageIndex and SelectImageIndex properties.
treeList1.ImageIndexFieldName = "ImageIndex";
// Data source for state (right) images.
treeList1.StateImageList = imageCollection1;
// Use the Load event to assign images to nodes.
treeList1.Load += TreeList1_Load;

private void TreeList1_Load(object sender, EventArgs e) {
    foreach (TreeListNode node in treeList1.Nodes) {
        // The left image displayed when the node is NOT focused.
        node.ImageIndex = 0;
        // The left image displayed when the node is focused.
        node.SelectImageIndex = 1;
        // The right image that does not depend on the focus.
        node.StateImageIndex = 2;
    }
}

VB.NET

Imports DevExpress.XtraTreeList.Nodes

' Data source for select (left) images.
treeList1.SelectImageList = imageCollection1
' Use the data source to assign select images to nodes.
' Data source fields do NOT allow you to specify
' two images that depend on the focus.
' This property has priority over the node's
' ImageIndex and SelectImageIndex properties.
treeList1.ImageIndexFieldName = "ImageIndex"
' Data source for state (right) images.
treeList1.StateImageList = imageCollection1
' Use the Load event to assign images to nodes.
AddHandler treeList1.Load, AddressOf TreeList1_Load

Private Sub TreeList1_Load(ByVal sender As Object, ByVal e As EventArgs)
    For Each node As TreeListNode In treeList1.Nodes
        ' The left image displayed when the node is NOT focused.
        node.ImageIndex = 0
        ' The left image displayed when the node is focused.
        node.SelectImageIndex = 1
        ' The right image that does not depend on the focus.
        node.StateImageIndex = 2
    Next node
End Sub