How do you get the root namespace of an assembly?

Question

Given an instance of System.Reflection.Assembly.

Answer 1

I have come across this dilemma plenty of times when I want to load a resource from the current assembly by its manifest resource stream.

The fact is that if you embed a file as a resource in your assembly using Visual Studio its manifest resource name will be derived from the default namespace of the assembly as defined in the Visual Studio project.

The best solution I've come up with (to avoid hardcoding the default namespace as a string somewhere) is to simply ensure your resource loading code is ALWAYS happening from inside a class that's also in the default namespace and then the following near-generic approach may be used.

This example is loading an embedded schema.

XmlSchema mySchema;
string resourceName = "MyEmbeddedSchema.xsd";
string resourcesFolderName = "Serialisation";
string manifestResourceName = string.Format("{0}.{1}.{2}",
    this.GetType().Namespace, resourcesFolderName, resourceName);
using (Stream schemaStream = currentAssembly.GetManifestResourceStream(manifestResourceName))
    mySchema = XmlSchema.Read(schemaStream, errorHandler);

See also: How to get Namespace of an Assembly?

Edit: Also noticed a very detailed answer to the question I'm answering at http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/3a469f5d-8f55-4b25-ac25-4778f260bb7e

Another edit in case people with same question come looking: Excellent idea to solve the resource-loading question here: How get the default namespace of project csproj (VS 2008)

Answer 2

Not possible. Nothing specifies a "Root" namespace. The default namespace in the options is a visual studio thing, not a .net thing

Answer 3

I just created an empty internal class called Root and put it in the project root (assuming this is your root namespace). Then I use this everywhere I need the root namespace:

typeof(Root).Namespace;

Sure I end up with an unused file, but it's clean.

Answer 4

There could be any number of namespaces in a given assembly, and nothing requires them to all start from a common root. The best you could do would be to reflect over all the types in an assembly and build up a list of unique namespaces contained therein.

Answer 5

Assemblies don't necessarily have a root namespace. Namespaces and Assemblies are orthogonal.

What you may be looking for instead, is to find a type within that Assembly, and then find out what its namespace is.

You should be able to accomplish this by using the GetExportedTypes() member and then using the Namespace property from one of the returned Type handles.

Again though, no guarantees all the types are in the same namespace (or even in the same namespace hierarchy).

Answer 6

I use typeof(App).Namespace in my WPF application. App class is mandatory for any WPF application and it's located in root.

Answer 7

GetType(frm).Namespace

frm is the startup Form

Answer 8

Get Types gives you a list of Type objects defined in the assembly. That object has a namespace property. Remember that an assembly can have multiple namespaces.

Answer 9

No, you cannot definitively know the default namespace that was set in an assembly' project file... but you can assume that most types declared in the assembly will be within the default namespace. My solution looks for the most popular namespace root which at least 80% (arbitrary choice) of the types in the assembly contained therein:

public static string? GetDefaultNamespace(this Assembly assembly, double threshold = 0.8)
{
    var types = assembly.GetTypes();
    int partIndex = 0;
    var parts = new List<string>();
    var ranked = types
        .Where(_ => _.Namespace != null)
        .GroupBy(_ => _.Namespace)
        .Select(_ => new { Parts = _.Key!.Split('.'), Count = _.Count() })
        .Where(_ => _.Parts.Length > partIndex)
        .GroupBy(_ => _.Parts[partIndex])
        .OrderByDescending(_ => _.Sum(x => x.Count))
        .ToArray();
    while (ranked.Any() && ranked[0].Sum(_ => _.Count) >= types.Length * threshold)
    {
        parts.Add(ranked[0].Key);
        partIndex++;
        ranked = ranked[0]
            .Where(_ => _.Parts.Length > partIndex)
            .GroupBy(_ => _.Parts[partIndex])
            .OrderByDescending(_ => _.Sum(x => x.Count))
            .ToArray();
   }
   return string.Join('.', parts);
}

Answer 10

There actually is an indirect way to get it, by enumerating the names of the assembly's manifest resources. The name you want ends with the part of it that you know.

Rather than repeat the code here, please see get Default namespace name for Assembly.GetManifestResourceStream() method

Answer 11

The question I had that landed me here was, "If I call library code N methods deep and want the namespace of the Project - for example the MVC app that's actually running - how do I get that?"

A little hacky but you can just grab a stacktrace and filter:

    public static string GetRootNamespace()
    {
        StackTrace stackTrace = new StackTrace();
        StackFrame[] stackFrames = stackTrace.GetFrames();
        string ns = null;
        foreach(var frame in stackFrames)
        {
            string _ns = frame.GetMethod().DeclaringType.Namespace;
            int indexPeriod = _ns.IndexOf('.');
            string rootNs = _ns;
            if (indexPeriod > 0)
                rootNs = _ns.Substring(0, indexPeriod);

            if (rootNs == "System")
                break;
            ns = _ns;
        }

        return ns;
    }

All this is doing is getting the stacktrace, running down the methods from most recently called to root, and filtering for System. Once it finds a System call it knows it's gone too far, and returns you the namespace immediately above it. Whether you're running a Unit Test, an MVC App, or a Service, the System container is going to be sitting 1 level deeper than the root namespace of your Project, so voila.

In some scenarios where System code is an intermediary (like System.Task) along the trace this is going to return the wrong answer. My goal was to take for example some startup code and let it easily find a class or Controller or whatever in the root Namespace, even if the code doing the work sits out in a library. This accomplishes that task.

I'm sure that can be improved - I'm sure this hacky way of doing things can be improved in many ways, and improvements are welcome.

Answer 12

Adding to all the other answers here, hopefully without repeating information, here is how I solved this using Linq. My situation is similar to Lisa's answer.

My solution comes with the following caveats:

• You're using Visual Studio and have a Root Namespace defined for your project, which I assume is what you're asking for since you use the term "root namespace"
• You're not embedding interop types from referenced assemblies

Dim baseNamespace = String.Join("."c,
    Me.GetType().Assembly.ManifestModule.GetTypes().
        Select(Function(type As Type)
                    Return type.Namespace.Split("."c)
                End Function
        ).
        Aggregate(Function(seed As String(), splitNamespace As String())
                        Return seed.Intersect(splitNamespace).ToArray()
                    End Function
        )
)

Answer 13

Here as a rather simple way to get the root namespace for a website project.

''' <summary>
''' Returns the namespace of the currently running website
''' </summary>
Public Function GetWebsiteRootNamespace() As String
    For Each Asm In AppDomain.CurrentDomain.GetAssemblies()
        If Asm Is Nothing OrElse Asm.IsDynamic Then Continue For

        For Each Typ In Asm.GetTypes
            If Typ Is Nothing OrElse Typ.Name Is Nothing Then Continue For
            If Typ.Name = "MyProject" Then Return Typ.Namespace.Split("."c)(0)
        Next
    Next

    Return Nothing
End Function

This simply checks all the loaded assemblies for the "MyProject" type and returns the root namespace for that type. This is useful for logging when you have multiple web projects in a single solution sharing a log system. Hope this helps someone.

Answer 14

This solution works if you are trying to load an embedded resource.

var assembly = System.Reflection.Assembly.GetExecutingAssembly();
string[] resourceNames = assembly.GetManifestResourceNames();

string  resourceNameNoNamespace = $"Languages.{languageSupport.IsoCode}.Languages.xml";
var match = resourceNames.SingleOrDefault(rn => rn.EndsWith(resourceNameNoNamespace));

Answer 15

Dim applicationNamespace = TextBeforeFirst(Assembly.GetCallingAssembly().EntryPoint.DeclaringType.Namespace, ".")

Public Function TextBeforeFirst(value As String, expression As String) As String
  If String.IsNullOrEmpty(value) Or String.IsNullOrEmpty(expression) Then Return Nothing
  Dim index = value.IndexOf(expression)
  If index = -1 Then Return Nothing
  Dim length = index
  Return value.Substring(0, length)
End Function

Answer 16

Namespaces have nothing to do with assemblies - any mapping between a namespace and the classes in an assembly is purely due to a naming convention (or coincidence).