UriTemplate Class

A URI template allows you to define a set of structurally similar URIs. Templates are composed of two parts, a path and a query. A path consists of a series of segments delimited by a slash (/). Each segment can have a literal value, a variable value (written within curly braces [{ }], constrained to match the contents of exactly one segment), or a wildcard (written as an asterisk [*], which matches "the rest of the path"), which must appear at the end of the path. The query expression can be omitted entirely. If present, it specifies an unordered series of name/value pairs. Elements of the query expression can be either literal pairs (?x=2) or variable pairs (?x={val}). Unpaired values are not permitted. The following examples show valid template strings:

• "weather/WA/Seattle"

• "weather/{state}/{city}"

• "weather/*"

• "weather/{state}/{city}?forecast=today

• "weather/{state}/{city}?forecast={day}

The preceding URI templates might be used for organizing weather reports. Segments enclosed in curly braces are variables, everything else is a literal. You can convert a UriTemplate instance into a Uri by replacing variables with actual values. For example, taking the template "weather/{state}/{city}" and putting in values for the variables "{state}" and "{city}" gives you "weather/WA/Seattle". Given a candidate URI, you can test whether it matches a given URI template by calling Match(Uri, Uri). You can also use UriTemplate instances to create a Uri from a set of variable values by calling BindByName(Uri, NameValueCollection) or BindByPosition(Uri, String[]).

The following code demonstrates how to create a UriTemplate instance, and bind and match it to a candidate URI.

UriTemplate template = new UriTemplate("weather/{state}/{city}?forecast={day}");
Uri prefix = new Uri("http://localhost");

Console.WriteLine("PathSegmentVariableNames:");
foreach (string name in template.PathSegmentVariableNames)
{
    Console.WriteLine("     {0}", name);
}
Console.WriteLine();

Console.WriteLine("QueryValueVariableNames:");
foreach (string name in template.QueryValueVariableNames)
{
    Console.WriteLine("     {0}", name);
}
Console.WriteLine();

Uri positionalUri = template.BindByPosition(prefix, "Washington", "Redmond", "Today");

NameValueCollection parameters = new NameValueCollection();
parameters.Add("state", "Washington");
parameters.Add("city", "Redmond");
parameters.Add("day", "Today");
Uri namedUri = template.BindByName(prefix, parameters);

Uri fullUri = new Uri("http://localhost/weather/Washington/Redmond?forecast=today");
UriTemplateMatch results = template.Match(prefix, fullUri);

Console.WriteLine("Matching {0} to {1}", template.ToString(), fullUri.ToString());

if (results != null)
{
    foreach (string variableName in results.BoundVariables.Keys)
    {
        Console.WriteLine("   {0}: {1}", variableName, results.BoundVariables[variableName]);
    }
}

.NET Framework

.NET Framework Client Profile

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference