You can use a dictionary to bind
<asp:datalist id="datalist" runat="server" datakeyfield="Key" xmlns:asp="#unknown">
<itemtemplate>
<asp:label runat="server" text="<%# Eval("Value") %>"></asp:label>
</itemtemplate>
</asp:datalist>
Code
Dictionary<string,> dictionary = new Dictionary<string,>()
{
{"a", "aaa"},
{"b", "bbb"},
{"c", "ccc"}
};
datalist.DataSource = dictionary;
datalist.DataBind();