Решение:
В самом UserControl:
<link href="<%= GetCssUrl() %>" rel="stylesheet" type="text/css" /> private string _cssFile = "Calculator.css"; public string CssFile {
set { _cssFile = value; } get { return _cssFile; } } public string GetCssUrl() { string cssRoot = System.Web.VirtualPathUtility.ToAbsolute("~/Controls/Gallery"); string result = string.Format("{0}/{1}", cssRoot, СssFile); return result; }
На целевой странице:
<uc1:Calculator ID="Calculator1" runat="server" CssFile="PrintCalculator.css" /> <asp:Button ID="Button1" runat="server" Text="Button" onclick="Button1_Click" /> protected void Button1_Click(object sender, EventArgs e) { Calculator1.CssFile = "Calculator.css";