Hi,
the Container property needs as a paramater WebPartContainerInfo object, not string. Could you please try to use following code:
<uc1:repeater ID="rptNestedPage" runat="server" ClassNames="cms.menuitem" TransformationName="CMS.MenuItem.inner" />
<script runat="server">
protected void Page_Load(object sender, EventArgs e)
{
//Black.Box is a code name of container (Site Manager - Development - Web part //containers)
rptNestedPage.Container = CMS.PortalEngine.WebPartContainerInfoProvider.GetWebPartContainerInfo("Black.Box");
}
If it does not work, you can set properties ContentBefore, ContentAfter to simulate the container.
Best regards,
Ivana Tomanickova