String Extension Methods in Razor

The Razor view engine provides helpful extension methods for views that handle type detection and conversion of string values. Here is an example:

@{
    if (Request.QueryString["amount"].IsDecimal())
    {
        @Request.QueryString["amount"].AsDecimal().ToString("c")
    }
    else
    {
        @: Amount is not a valid number
    }
}

Extension methods exist in pairs: Is(Type) and As(Type) methods for bools, datetimes, decimals, floats, and ints. The As(Type) conversion methods accept an optional second parameter serving as a default value if conversion fails.

These utilities reside in the System.Web.WebPages namespace, which MVC3 and Webmatrix projects reference by default. Developers can add a using statement to System.Web.WebPages to leverage these methods in their views when needed.