TreeView.SelectedImageIndex Property

Definition

Gets or sets the image list index value of the image that is displayed when a tree node is selected.

C#
[System.ComponentModel.TypeConverter(typeof(System.Windows.Forms.TreeViewImageIndexConverter))]
public int SelectedImageIndex { get; set; }
C#
[System.ComponentModel.TypeConverter(typeof(System.Windows.Forms.NoneExcludedImageIndexConverter))]
[System.Windows.Forms.RelatedImageList("ImageList")]
public int SelectedImageIndex { get; set; }

Property Value

A zero-based index value that represents the position of an Image in an ImageList.

Attributes

Exceptions

value is less than -1.

Examples

The following code example creates and assigns an ImageList to a TreeView control and fills the TreeView control with TreeNode objects. The tree nodes are assigned images from the ImageList that are displayed when in a selected or unselected state. This example requires that you have a Form that contains a TreeView, and an ArrayList that contains Customer objects that each contain Order objects. It is also assumed that the Customer and Order objects are defined.

C#

public class Customer
{
   public ArrayList CustomerOrders;
   public string CustomerName;
   public Customer(string myName)
   {
      CustomerName = myName;
      CustomerOrders = new ArrayList(); 
   }
}
public class Order
{
   public string OrderID;
   public Order(string myOrderID )
   {
      this.OrderID = myOrderID;
   }
}

private void FillTreeView()
{
    // Load the images in an ImageList.
    ImageList myImageList = new ImageList();
    myImageList.Images.Add(Image.FromFile("Default.gif"));
    myImageList.Images.Add(Image.FromFile("SelectedDefault.gif"));
    myImageList.Images.Add(Image.FromFile("Root.gif"));
    myImageList.Images.Add(Image.FromFile("UnselectedCustomer.gif"));
    myImageList.Images.Add(Image.FromFile("SelectedCustomer.gif"));
    myImageList.Images.Add(Image.FromFile("UnselectedOrder.gif"));
    myImageList.Images.Add(Image.FromFile("SelectedOrder.gif"));
    
    // Assign the ImageList to the TreeView.
    myTreeView.ImageList = myImageList;
    
    // Set the TreeView control's default image and selected image indexes.
    myTreeView.ImageIndex = 0;
    myTreeView.SelectedImageIndex = 1;

    /* Set the index of image from the 
    ImageList for selected and unselected tree nodes.*/
    this.rootImageIndex = 2;
    this.selectedCustomerImageIndex = 3;
    this.unselectedCustomerImageIndex = 4;
    this.selectedOrderImageIndex = 5;
    this.unselectedOrderImageIndex = 6;
    
    // Create the root tree node.
    TreeNode rootNode = new TreeNode("CustomerList");
    rootNode.ImageIndex = rootImageIndex;
    rootNode.SelectedImageIndex = rootImageIndex;
      
    // Add a main root tree node.
    myTreeView.Nodes.Add(rootNode);

    // Add a root tree node for each Customer object in the ArrayList.
    foreach(Customer myCustomer in customerArray)
    {
        // Add a child tree node for each Order object.
        int countIndex=0;
        TreeNode[] myTreeNodeArray = new TreeNode[myCustomer.CustomerOrders.Count];
        foreach(Order myOrder in myCustomer.CustomerOrders)
        {
            // Add the Order tree node to the array.
            myTreeNodeArray[countIndex] = new TreeNode(myOrder.OrderID,
              unselectedOrderImageIndex, selectedOrderImageIndex);
            countIndex++;
        }
        // Add the Customer tree node.
        TreeNode customerNode = new TreeNode(myCustomer.CustomerName,
            unselectedCustomerImageIndex, selectedCustomerImageIndex, myTreeNodeArray);
        myTreeView.Nodes[0].Nodes.Add(customerNode);
    }
}

Remarks

The SelectedImageIndex value is the index of an Image stored in the ImageList assigned to the ImageList property.

Note

When setting the SelectedImageIndex property at run time, the TreeView handle is recreated (see Control.RecreateHandle) to update the control's appearance. This causes all tree nodes to be collapsed, except for the selected TreeNode.

SelectedImageKey and SelectedImageIndex are mutually exclusive, meaning if one is set, the other is set to an invalid value and ignored. If you set the SelectedImageKey property, the SelectedImageIndex property is automatically set to -1. Alternatively, if you set the SelectedImageIndex property, the SelectedImageKey is automatically set to an empty string ("").

Applies to

Product Versions
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
Windows Desktop 3.0, 3.1, 5, 6, 7, 8, 9

See also