Insert Html.RenderAction("CartSummary", "ShoppingCart") To Dynamic String?

I have dynamic strings, for example

hello bold italic {0} xxx {0}y开发者_如何学运维yy {0} etc...,

abcd {0} how to xyz {0} newline {0}..etc...,

and more.

How to insert <% Html.RenderAction("CartSummary", "ShoppingCart"); %> to the dynamic string at the {0} position?

Html.RenderAction writes directly to the response. You could use Html.Action which returns an MvcHtmlString.