How to set focus to a MS ASP.NET TreeView on form load

Introduction

People have been having problems using the TreeView control from Microsoft, for ASP.NET:

Microsoft.Web.UI.WebControls.TreeView

This control can be download for free from the Microsoft website. This page contains an overview of the free web controls (not supported by MS).

We will cover the focus issues for this control in this article. The reason I chose to create this article is that there was not much information after searching multiple sites. Basically this article will explain the two main problems: trying to get a TreeView control to have focus and setting the colors properly, for hover and selected items.

Main information

Here is a list of problems trying to set focus to the Microsoft ASP.NET TreeView control:

1. Even though you place the TreeView inside a form, you have to use the document object instead of the form object to set the focus. Here is the final code:

   Private Sub focusTreeview()
     Dim strBuilder As StringBuilder = New StringBuilder()
     strBuilder.Append("<script language='javascript'>")
     strBuilder.Append("document.getElementById('TreeView1').focus();")
      
     'Following line does nothing
     'strBuilder.Append("document.getElementById('TreeView1').select();") 
     strBuilder.Append("</script>")
     RegisterStartupScript("FocusTreeview", strBuilder.ToString)
   End Sub

   After you use the code above, the TreeView will be selected on form load and user can properly select any item from the TreeView.

2. Once you use the document's focus method, the colors stay in "light" mode no matter what you do, but, the TreeView is actually selected correctly.
3. The "select" statement does not have any effect on the TreeView. So if you un-comment the line above, it will have no effect on the TreeView.
4. The way to make the colors not be in "light" mode is by using the filter style attribute in the SelectedStyle and HoverStyle as follows:

   <iewc:treeview id="TreeView1"
   runat="server"
   DefaultStyle="font-family:arial;font-size:8pt;"
   SelectedStyle="filter=none;background-color:orange;
   font-weight:bold;" HoverStyle="filter=none;background-color:green;">
   </iewc:treeview>

Notes

1. The filter=none has to go before the other style keywords, if not you will just get a grey color.
2. Be sure to add Imports System.Text to the top of your code in order to use the StringBuilder object.
3. The features described in this article only apply to MS Internet Explorer 6.x.