Type.GetType(“namespace.a.b.ClassName”) returns null

Problem

This code:

Type.GetType("namespace.a.b.ClassName")

returns null.

I’ve got the following in the usings:

using namespace.a.b;

Update:

I need to get the type by string name because it exists but is in a separate class library.

Asked by Omu

Solution #1

Only when the type is found in either mscorlib.dll or the presently executing assembly does Type.GetType(“namespace.qualified.TypeName”) work.

You’ll need an assembly-qualified name if none of those things are true:

Type.GetType("namespace.qualified.TypeName, Assembly.Name")

Answered by DrPizza

Solution #2

You can also get the type without the assembly qualified name but with the dll name:

Type myClassType = Type.GetType("TypeName,DllName");

It worked for me when I was in the same scenario. I required a “DataModel.QueueObject” object and had a reference to “DataModel,” so I created one as follows:

Type type = Type.GetType("DataModel.QueueObject,DataModel");

The reference name is the second string following the comma (dll name).

Answered by Asaf Pala

Solution #3

Try this method.

public static Type GetType(string typeName)
{
    var type = Type.GetType(typeName);
    if (type != null) return type;
    foreach (var a in AppDomain.CurrentDomain.GetAssemblies())
    {
        type = a.GetType(typeName);
        if (type != null)
            return type;
    }
    return null;
}

Answered by peyman

Solution #4

You can use the BuildManager class if the assembly is part of an ASP.NET application’s build:

using System.Web.Compilation
...
BuildManager.GetType(typeName, false);

Answered by LarryBud

Solution #5

Dictionary<string, Type> typeCache;
...
public static bool TryFindType(string typeName, out Type t) {
    lock (typeCache) {
        if (!typeCache.TryGetValue(typeName, out t)) {
            foreach (Assembly a in AppDomain.CurrentDomain.GetAssemblies()) {
                t = a.GetType(typeName);
                if (t != null)
                    break;
            }
            typeCache[typeName] = t; // perhaps null
        }
    }
    return t != null;
}

Answered by erikkallen

Post is based on https://stackoverflow.com/questions/1825147/type-gettypenamespace-a-b-classname-returns-null