Route.Defaults Property

public:
 property System::Web::Routing::RouteValueDictionary ^ Defaults { System::Web::Routing::RouteValueDictionary ^ get(); void set(System::Web::Routing::RouteValueDictionary ^ value); };

public System.Web.Routing.RouteValueDictionary Defaults { get; set; }

member this.Defaults : System.Web.Routing.RouteValueDictionary with get, set

Public Property Defaults As RouteValueDictionary

An object that contains the parameter names and default values.

The following example shows how to create a Route object and set the Constraints, DataTokens, and Defaults properties.

void Application_Start(object sender, EventArgs e) 
{
    RegisterRoutes(RouteTable.Routes);
}

public static void RegisterRoutes(RouteCollection routes)
{
    Route reportRoute = new Route("{locale}/{year}", new ReportRouteHandler());
    reportRoute.Defaults = new RouteValueDictionary { { "locale", "en-US" }, { "year", DateTime.Now.Year.ToString() } };
    reportRoute.Constraints = new RouteValueDictionary { { "locale", "[a-z]{2}-[a-z]{2}" }, { "year", @"\d{4}" } };
    reportRoute.DataTokens = new RouteValueDictionary { { "format", "short" } };
    routes.Add(reportRoute);
}

Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
    RegisterRoutes(RouteTable.Routes)
End Sub

Shared Sub RegisterRoutes(ByVal routes As RouteCollection)
    Dim urlPattern As String
    Dim reportRoute As Route
    
    urlPattern = "{locale}/{year}"
    
    reportRoute = New Route(urlPattern, New ReportRouteHandler)
    reportRoute.Defaults = New RouteValueDictionary(New With {.locale = "en-US", .year = DateTime.Now.Year.ToString()})
    reportRoute.Constraints = New RouteValueDictionary(New With {.locale = "[a-z]{2}-[a-z]{2}", .year = "\d{4}"})
    reportRoute.DataTokens = New RouteValueDictionary(New With {.format = "short"})

    routes.Add(reportRoute)
End Sub

The following example shows a Route object whose Defaults property contains a parameter that is not part of the pattern in the Url property.

void Application_Start(object sender, EventArgs e) 
{
    RegisterRoutes(RouteTable.Routes);
}

public static void RegisterRoutes(RouteCollection routes)
{
    Route reportRoute = new Route("{locale}/{year}", new ReportRouteHandler());
    
    reportRoute.Defaults = new RouteValueDictionary { { "months", "all" } };
    
    routes.Add(reportRoute);
}

Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
    RegisterRoutes(RouteTable.Routes)
End Sub

Shared Sub RegisterRoutes(ByVal routes As RouteCollection)
    Dim urlPattern As String
    Dim reportRoute As Route
    
    urlPattern = "{locale}/{year}"
    
    reportRoute = New Route(urlPattern, New ReportRouteHandler)
    
    reportRoute.Defaults = New RouteValueDictionary(New With {.months = "all"})
    
    routes.Add(reportRoute)
End Sub

The Defaults property enables you to set the value for a URL parameter if the URL does not contain a segment for that parameter. You assign a RouteValueDictionary object to the Defaults property. Each element in the RouteValueDictionary object contains the name of a parameter and the value to use if the parameter is missing.

You can include a default value for a parameter that is not defined in the Url property as a segment. When ASP.NET routing handles a request, this default value is always passed to the route handler. When you construct a URL and you include a value for a default parameter that is not defined as a segment, the route will only be considered a match if the value that you provided matches the default value for the route.

• ASP.NET Routing