Both controls can represent XML hierarchical data and support Extensible Stylesheet Language (XSL) templates, which can be used to transform an XML file into a the correct format and structure. While TreeView can apply Styles more easily, provide special properties that simplify the customization of the appearance of elements based on their current state.

<asp:TreeView ID="TreeView1" runat="server" DataSourceID="siteMapDataSource"
ImageSet="Faq" SkipLinkText =""> 
<ParentNodeStyle Font-Bold="False" /> 
<HoverNodeStyle Font-Underline="True" ForeColor="Purple" />   
<SelectedNodeStyle Font-Underline="True" HorizontalPadding="0px"
VerticalPadding="0px" /> 
<NodeStyle Font-Names="Tahoma" Font-Size="8pt" ForeColor="DarkBlue"
HorizontalPadding="5px" NodeSpacing="0px" VerticalPadding="0px" />
</asp:TreeView>
<asp:SiteMapDataSource ID="siteMapDataSource"  runat="server" />                    

Figure: Good Code - Use TreeView to represent XML hierarchical data

<asp:Xml ID="Xml1" runat="server" DocumentSource="~/Web.xml"
TransformSource="~/Style.xsl"></asp:Xml> 

Figure: Bad Code - Use XML to represent XML document using XSL Transformations