c# - Reflection usage for creating instance of a class into DLL -

i have following code:

var type = typeof(plugininterface.imbddxplugininterface); var types = appdomain.currentdomain.getassemblies().tolist()     .selectmany(s => s.gettypes())     .where(p => type.isassignablefrom(p));  type t = types.elementat(0); plugininterface.imbddxplugininterface instance = activator.createinstance(t) plugininterface.imbddxplugininterface; tabpage tp = new tabpage();  tp = instance.plugintabpage(); 

the class within dll implements plugininterface , type in code above, definately correct class/type, when try create instance through interface error message saying:

object reference not assigned instance of object.

anybody know why?

thanks.

anyway

tabpage tp = new tabpage(); tp = instance.plugintabpage(); 

makes no sense.

do:

tabpage tp = instance.plugintabpage(); 

---

also next:

type type = appdomain.currentdomain.getassemblies()     .selectmany(s => s.gettypes())     .firstordefault(p => type.isassignablefrom(p)); if (type != null) {     // create instance } 

or (my preferred way):

from asm in appdomain.currentdomain.getassemblies() type in asm.gettypes() !type.isinterface && !type.isabstract && typeof(itarget).isassignablefrom(type) select (itarget)activator.createinstance(type);