I want to hide Edit button on detailsView if a user is not authorized to edit so that the user can only view the details. 

One option is to display your Edit Button within a TemplateField and call a small helper function in the code-behind like so:

ASPX 

<asp:linkbutton id="btnEdit" runat="server" commandname="Edit" text="Edit" visible='<%# AuthorizedToEdit() %>' />

CODE-BEHIND 

protected bool AuthorizedToEdit()
{
	return // some boolean expression here to indicate permission to edit
}

thanks, Ed.  Could you please modify the following code for me?

This is hard to do since I have no idea how your application is configured for security. Most often, this would simply be a call to see if the currently logged-in user was in a particular role or not. Something like this:

return Roles.IsUserInRole(this.User.Identity.Name, "Edit");

my problem is not how to write the boolean expression but how to convert your code to VB.net

please read the error i got and reply if you can. 

thanks.

Use a Function as oposed to a Sub: 

Protected Function AuthorizedToEdit() As Boolean
	Return True
End Function

thanks. Ed.

Methods can be declared as a Sub or a Function. A Sub is a method that doesn't return anything and a Function is a method that does return something.