I use VS2008 ASP C# .NET 3.5 and use the codebehind page almost exclusively. I need to to call the <eo:Dialog> to open under IF Else conditions like so:

if (User.IsInRole("Administrators"))
{
// open eo.web.editor......
}
else
{
Dialog1 show, open, etc...
}

[asp]
<eo:CallbackPanel runat="server" ID="CallbackPanel1" LoadingDialogID="Dialog1" Triggers="{ControlID:Button1;Parameter:}">
<p>
Some Input:
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox></p>
<p>
<asp:Button ID="Button1" runat="server" Text="Submit"></asp:Button></p>
<p>
<asp:Label ID="lblResult" runat="server"></asp:Label></p>
</eo:CallbackPanel>
<eo:Dialog runat="server" ID="Dialog1" BackShadeColor="Blue">
<ContentTemplate>
<table border="0">
<tr>
<td align="center">
<!-- <img src="Images/loading.gif" /> -->
</td>
</tr>
<tr>
<td>
You do not have sufficient permissions to edit this page!
</td>
</tr>
</table>
</ContentTemplate>
</eo:Dialog>

Are you saying keep only the Dialog code and calling Dialog1.Visible = true ?

[.cs]
}
else
{
Dialog1.Visible = true;
}

[asp]
<eo:Dialog runat="server" ID="Dialog1" BackShadeColor="Red" Visible="false">
<ContentTemplate>
<table border="0">
<tr>
<td align="center">
<!-- <img src="Images/loading.gif" /> -->
</td>
</tr>
<tr>
<td>
You do not have sufficient permissions to edit this page!
</td>
</tr>
</table>
</ContentTemplate>
</eo:Dialog>