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

Question

This code:

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

returns null.

and I have in the usings:

using nam         


        

Answer 1

I am opening user controls depending on what user controls the user have access to specified in a database. So I used this method to get the TypeName...

Dim strType As String = GetType(Namespace.ClassName).AssemblyQualifiedName.ToString
Dim obj As UserControl = Activator.CreateInstance(Type.GetType(strType))

So now one can use the value returned in strType to create an instance of that object.

Answer 2

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;
}

Answer 3

Type.GetType("namespace.qualified.TypeName") only works when the type is found in either mscorlib.dll or the currently executing assembly.

If neither of those things are true, you'll need an assembly-qualified name:

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

Answer 4

When I have only the class name I use this:

Type obj = AppDomain.CurrentDomain.GetAssemblies().SelectMany(t => t.GetTypes()).Where(t => String.Equals(t.Name, _viewModelName, StringComparison.Ordinal)).First();

Answer 5

As Type.GetType(String) need the Type.AssemblyQualifiedName you should use Assembly.CreateQualifiedName(String, String).

string typeName = "MyNamespace.MyClass"; // Type.FullName
string assemblyName = "MyAssemblyName"; // MyAssembly.FullName or MyAssembly.GetName().Name
string assemblyQualifiedName = Assembly.CreateQualifiedName(assemblyName , typeName);
Type myClassType = Type.GetType(assemblyQualifiedName);

The Version, Culture and PublicKeyToken are not required for assemblyName that's why you can use MyAssembly.GetName().Name.

About Type.GetType(String) :

If the type is in the currently executing assembly or in Mscorlib.dll, it is sufficient to supply the type name qualified by its namespace.

Answer 6

If the assembly is part of the build of an ASP.NET application, you can use the BuildManager class:

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