ASP.NET TreeView and SiteMap : 5 Common Tips
In this article, we will see 5 common tips when using the ASP.NET TreeView control bound with a SiteMap. It’s very common to display the SiteMap using the TreeView control. The tips shown in this article cover some frequent challenges we face when using these controls. I assume you know what a sitemap is and have also used the TreeView control.
1. How to Bind an ASP.NET TreeView to a SiteMap
A sitemap is usually displayed in the UI using a Treeview control. A sample Web.Sitemap is shown below:
<?xml version="1.0" encoding="utf-8" ?>
<siteMap xmlns="http://schemas.microsoft.com/AspNet/SiteMap-File-1.0" >
<siteMapNode title="My Favorites">
<siteMapNode title="Favorite Sites">
<siteMapNode title="ASP.NET Home" url="http://www.asp.net" />
<siteMapNode title="ASP.NET Articles" url="https://www.dotnetcurry.com" />
<siteMapNode title="Windows Client" url="http://www.windowsclient.net" />
<siteMapNode title="Silverlight" url="http://silverlight.net" />
</siteMapNode>
<siteMapNode title="Favorite Blogs">
<siteMapNode title="ScottGu Blog"url="http://weblogs.asp.net/scottgu" />
<siteMapNode title="Technology Blog" url="http://www.devcurry.com" />
<siteMapNode title="SQL Blog" url="http://www.sqlservercurry.com" />
<siteMapNode title="Food Lovers" url="http://foodatarian.com" />
</siteMapNode>
</siteMapNode>
</siteMap>
Now add a SiteMapDataSource Control from the toolbox (Data tab) to your page and set the DataSource property of the TreeView to this SiteMapDataSource as shown below:
<div>
<asp:TreeView ID="TreeView1" runat="server" DataSourceID="SiteMapDataSource1">
</asp:TreeView>
<asp:SiteMapDataSource ID="SiteMapDataSource1" runat="server" />
</div>
That’s it.
2. Remove A Node from the ASP.NET TreeView Dynamically
In order to remove a node dynamically from the TreeView bound to a sitemap, use the ontreenodedatabound event as shown below. In this sample, I am removing the “Food Lovers” node for demonstration sake:
<asp:TreeView ID="TreeView1" runat="server" DataSourceID="SiteMapDataSource1"
ontreenodedatabound="TreeView1_TreeNodeDataBound">
</asp:TreeView>
C#
protected void TreeView1_TreeNodeDataBound(object sender, TreeNodeEventArgs e)
{
if (e.Node.Text == "Food Lovers")
{
e.Node.Parent.ChildNodes.Remove(e.Node);
}
}
VB.NET
Protected Sub TreeView1_TreeNodeDataBound(ByVal sender As Object, ByVal e As TreeNodeEventArgs)
If e.Node.Text = "Food Lovers" Then
e.Node.Parent.ChildNodes.Remove(e.Node)
End If
End Sub
As you can see in the image below, the ‘Food Lovers’ node is not displayed.
3. How to expand only one parent node of the ASP.NET Treeview control bound to a SiteMap
Have you faced a requirement where only one parent node should be expanded at any given point of time? For example, if the ‘Favorite Blogs’ node is expanded and the user clicks on the ‘Favorite Sites’ node to expand it, the ‘Favourite Blogs’ node should collapse. Use the following code in the TreeNodeExpanded event
C#
protected void TreeView1_TreeNodeExpanded(object sender,
TreeNodeEventArgs e)
{
string currValue = e.Node.Value.Trim();
if (e.Node.Parent == null)
{
foreach (TreeNode node in TreeView1.Nodes)
{
if (node.Value != currValue)
{
node.Collapse();
}
}
return;
}
else
{
TreeNode tnode = e.Node.Parent;
foreach (TreeNode node in tnode.ChildNodes)
{
if (node.Value != e.Node.Value)
{
node.Collapse();
}
}
}
}
VB.NET
Protected Sub TreeView1_TreeNodeExpanded(ByVal sender As Object, ByVal e As TreeNodeEventArgs)
Dim currValue As String = e.Node.Value.Trim()
If e.Node.Parent Is Nothing Then
For Each node As TreeNode In TreeView1.Nodes
If node.Value <> currValue Then
node.Collapse()
End If
Next node
Return
Else
Dim tnode As TreeNode = e.Node.Parent
For Each node As TreeNode In tnode.ChildNodes
If node.Value <> e.Node.Value Then
node.Collapse()
End If
Next node
End If
End Sub
The output is as shown below:
As you can see, the ‘Favorite Blogs’ node collapses when the user clicks on the ‘Favorite Sites’ node.
4. Multiple SiteMaps Bound to Multiple TreeViews
By default, when you add a new sitemap to your project, the default file created is the Web.SiteMap. The SiteMapDataSource by default refers to this file. However if you would like to create multiple sitemaps and bind them to different treeview’s in your project, then here’s how to do so:
Add a set of providers in the web.config file as shown below:
<system.web>
<siteMap defaultProvider="SiteMap1" enabled="true">
<providers>
<add siteMapFile="Web.sitemap" name="SiteMap1" type="System.Web.XmlSiteMapProvider"/>
<add siteMapFile="web2.sitemap" name="SiteMap2" type="System.Web.XmlSiteMapProvider"/>
</providers>
</siteMap>
Note: The defaultProvider is the name of the provider, in our case SiteMap1
Now in the SiteMapDataSource, specify the provider you want to use. Observe the ‘SiteMapProvider’ attribute.
<asp:SiteMapDataSource ID="SiteMapDataSource1" runat="server"
SiteMapProvider="SiteMap1" />
<asp:SiteMapDataSource ID="SiteMapDataSource2" runat="server"
SiteMapProvider="SiteMap2" />
Finally bind the TreeView DataSource to the desired SiteMapDataSource
<asp:TreeView ID="TreeView1" runat="server"
DataSourceID="SiteMapDataSource1">
<asp:TreeView ID="TreeView2" runat="server"
DataSourceID="SiteMapDataSource2">
This way you can have multiple sitemap files bound to multiple TreeView controls.
5. Adding AlternateUrl’s in the SiteMap node and Binding to the ASP.NET TreeView
Let’s say you want to specify an alternate url in the SiteMap and want to bind the TreeView to this alternate url at runtime, here’s how to do so
Declare a custom attribute called ‘secondUrl’ (or anything you want) on the SiteMapNode in the SiteMap file as shown below:
<siteMapNode title="ASP.NET Home" url="http://www.asp.net" secondUrl="http://www.asp.net/ajax" />
Now in the TreeNodeDataBound event, retrieve the SiteMapNode and for those nodes that have this custom attribute set. Once the SiteMapNode is retrieved, extract this custom attribute and set the NavigateUrl property as shown below:
<asp:TreeView ID="TreeView1" runat="server"
DataSourceID="SiteMapDataSource1"
OnTreeNodeDataBound="TreeView1_TreeNodeDataBound">
</asp:TreeView>
C#
protected void TreeView1_TreeNodeDataBound(object sender, TreeNodeEventArgs e)
{
SiteMapNode node = e.Node.DataItem as SiteMapNode;
if(!string.IsNullOrEmpty(node["secondUrl"]))
e.Node.NavigateUrl = node["secondUrl"];
}
VB.NET
Protected Sub TreeView1_TreeNodeDataBound(ByVal sender As Object, ByVal e As TreeNodeEventArgs)
Dim node As SiteMapNode = TryCast(e.Node.DataItem, SiteMapNode)
If (Not String.IsNullOrEmpty(node("secondUrl"))) Then
e.Node.NavigateUrl = node("secondUrl")
End If
End Sub
Those were some common tips associated with the TreeView control bound to the SiteMap file. I hope this article was useful and I thank you for viewing it.
This article has been editorially reviewed by Suprotim Agarwal.
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Suprotim Agarwal, MCSD, MCAD, MCDBA, MCSE, is the founder of
DotNetCurry,
DNC Magazine for Developers,
SQLServerCurry and
DevCurry. He has also authored a couple of books
51 Recipes using jQuery with ASP.NET Controls and
The Absolutely Awesome jQuery CookBook.
Suprotim has received the prestigious Microsoft MVP award for ten consecutive times. In a professional capacity, he is the CEO of A2Z Knowledge Visuals Pvt Ltd, a digital group that offers Digital Marketing and Branding services to businesses, both in a start-up and enterprise environment.
Get in touch with him on Twitter @suprotimagarwal or at LinkedIn