Your item ItemTemplate needs to define how each record will be displayed.
When you set your datasource to "gc" and databind it, the Eval in your ItemTemplate is going to check the gc object for a property named "gc" which of course it does not and that is why you get the error.
Say, for example, that your GlassesCollection contains objects of type Glass and that the Glass class contains two properties Id and Description. Then, if you want to use the repeater control, you would have an itemtemplate something like this
<itemtemplate>
Id = <%# Eval("Id") %>
Description = <%# Eval("Description") %>
</itemtemplate>
If you actually want your data in a grid type display, I would suggest that you use the DataGridView control instead.
<asp:datagridview id="dgData" runat="server" xmlns:asp="#unknown"></asp:datagridview>
dgData.Datasource = gc;
dgData.ResetBindings();