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TreeView.CollapseImageUrl Property

  • Reference

Definition

Namespace:
System.Web.UI.WebControls
Assembly:
System.Web.dll

Gets or sets the URL to a custom image for the collapsible node indicator.

public:
 property System::String ^ CollapseImageUrl { System::String ^ get(); void set(System::String ^ value); };
public string CollapseImageUrl { get; set; }
member this.CollapseImageUrl : string with get, set
Public Property CollapseImageUrl As String

Property Value

String

The URL to a custom image to display for collapsible nodes. The default is an empty string (""), which displays the default minus sign (-) image.

Examples

The following code example demonstrates how to use the CollapseImageUrl property to specify a custom image for the collapsible node indicator. For the code example to display and the image to appear in the control, you must provide your own image and the ImageSet property must be set to TreeNodeImageSet.Custom.


<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>TreeView Custom Images Example</title>
</head>
<body>
    <form id="form1" runat="server">
    
      <h3>TreeView Custom Images Example</h3>
      
      <!-- Set the custom images of this TreeView control -->
      <!-- declaratively.                                 -->
      <asp:TreeView id="CustomTreeView"
        NoExpandImageUrl="Space.jpg"
        CollapseImageUrl="Minus.jpg"
        CollapseImageToolTip="Collapse Node"
        ExpandImageUrl="Plus.jpg"
        ExpandImageToolTip="Expand Node"
        RootNodeStyle-ImageUrl="Root.jpg"
        ParentNodeStyle-ImageUrl="Parent.jpg"
        LeafNodeStyle-ImageUrl="Leaf.jpg" 
        ImageSet="Custom"
        runat="server">
         
        <Nodes>
        
          <asp:TreeNode Value="Home" 
            NavigateUrl="Home.aspx" 
            Text="Home"
            Target="_blank" 
            Expanded="True">
             
            <asp:TreeNode Value="Page 1" 
              NavigateUrl="Page1.aspx" 
              Text="Page 1"
              Target="_blank">
                 
              <asp:TreeNode Value="Section 1"
                ImageUrl="custom.jpg" 
                NavigateUrl="Section1.aspx" 
                Text="Section 1"
                Target="_blank">
              </asp:TreeNode>
                
            </asp:TreeNode>
            
            <asp:TreeNode Value="Page 2" 
              Selected="True" 
              NavigateUrl="Page2.aspx"
              Text="Page 2"
              Target="_blank">
            </asp:TreeNode>
            
          </asp:TreeNode>
        
        </Nodes>
        
      </asp:TreeView> 
       

    </form>
  </body>
</html>


<%@ Page Language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
  <head runat="server">
    <title>TreeView Custom Images Example</title>
</head>
<body>
    <form id="form1" runat="server">
    
      <h3>TreeView Custom Images Example</h3>
      
      <!-- Set the custom images of this TreeView control -->
      <!-- declaratively.                                 -->
      <asp:TreeView id="CustomTreeView"
        NoExpandImageUrl="Space.jpg"
        CollapseImageUrl="Minus.jpg"
        CollapseImageToolTip="Collapse Node"
        ExpandImageUrl="Plus.jpg"
        ExpandImageToolTip="Expand Node"
        RootNodeStyle-ImageUrl="Root.jpg"
        ParentNodeStyle-ImageUrl="Parent.jpg"
        LeafNodeStyle-ImageUrl="Leaf.jpg" 
        ImageSet="Custom"
        runat="server">
         
        <Nodes>
        
          <asp:TreeNode Value="Home" 
            NavigateUrl="Home.aspx" 
            Text="Home"
            Target="_blank" 
            Expanded="True">
             
            <asp:TreeNode Value="Page 1" 
              NavigateUrl="Page1.aspx" 
              Text="Page 1"
              Target="_blank">
                 
              <asp:TreeNode Value="Section 1"
                ImageUrl="custom.jpg" 
                NavigateUrl="Section1.aspx" 
                Text="Section 1"
                Target="_blank">
              </asp:TreeNode>
                
            </asp:TreeNode>
            
            <asp:TreeNode Value="Page 2" 
              Selected="True" 
              NavigateUrl="Page2.aspx"
              Text="Page 2"
              Target="_blank">
            </asp:TreeNode>
            
          </asp:TreeNode>
        
        </Nodes>
        
      </asp:TreeView> 
       

    </form>
  </body>
</html>

Remarks

Use the CollapseImageUrl property to specify a custom image for the collapsible node indicator. This image is displayed next to a collapsible node and is usually a minus sign (-).

When the ShowExpandCollapse property is set to true, the TreeView control displays a plus sign (+) or a minus sign(-) or a placeholder image next to a node to indicate whether the node is expandable, collapsible, or non-expandable, respectively. You can specify custom images by first setting the ImageSet property to TreeViewImageSet.Custom, and then setting the NoExpandImageUrl, ExpandImageUrl, and CollapseImageUrl properties to the URLs for the custom images. If no images are specified, the default images are used. To hide the expansion node indicators, set the ShowExpandCollapse property to false.

Note

To ensure that nodes align correctly in the TreeView control when using custom images, make sure that all the images that are specified by the NoExpandImageUrl, ExpandImageUrl, and CollapseImageUrl properties have the same dimensions.

When using a custom image for the collapsible node indicator, you should also consider setting the CollapseImageToolTip property to specify a ToolTip for the image.

The value of this property is stored in view state.

Applies to

See also