Compare types in a plugin API

[Jost Pedro]

Hi there, I’m trying to implement a plug in API in a application and I’m having problems in getting the Custom Attribute from an Assembly. First the custom attribute is something like this: [global::System.AttributeUsage(AttributeTargets.Assembly, Inherited = false, AllowMultiple = false)] public class AssemblyPluginAttribute : Attribute { readonly string pluginName; // This is a positional argument. public AssemblyPluginAttribute(string PluginName) { this.pluginName = PluginName; } public string PluginName { get { return this.pluginName; } } } Than in order to find a reference to this custom attribute I added to the plug-in project the following line. ... using Enki.UI.ComponentModel; [assembly: AssemblyPluginAttribute("TestPlugin")] namespace TestPlugin { ... Now ... to find if its a plug-in type assembly i look through the custom attributes of the assembly in order to find one matching with the one i defined (AssemblyPluginAttribute). The following line returns null list. Type AttType = typeof(Enki.UI.Plugins.AssemblyPluginAttribute); object[] obj = assembly.GetCustomAttributes(AttType, true); and the next one too... Attribute[] attlist= Attribute.GetCustomAttributes(assembly,AttType); but if instead of one of this two lines i use the following code ... foreach (Attribute att in Attribute.GetCustomAttributes(assembly)) { if (att.GetType().FullName.CompareTo(AttType.FullName)==0) return true; } ... it matches the full names!! I’ve tried many other ways to establish a possible comparison but none has the same result. I know, that if i found a way to get the result i desired i should stick to it an go on but I believe that this might lead me to a dead end in the future. Please, can anyone help me... to "see the light in the end of the tunnel"! :) Tanks Pedro M.

[led mike]

Here is the factory method I use in a plug-in application I have. You do not appear to have a need for the "ICustomAttributeHandler" aspect of the logic so you should ignore that part.

public static object newInstanceFromCustomAttribute( Assembly assm, System.Type tAttribute, ICustomAttributeHandler handler)
{
    object oret = null;
    Module[] modules = assm.GetModules(false);        // no resource modules needed
    for(int nMod=0; null == oret && nMod<modules.Length; nMod++)
    {
        Type[] types = modules[nMod].GetTypes();
        for(int nType=0; null == oret && nType<types.Length; nType++)
        {
            // get the array of attributes of our target type
            object[] attributes = types[nType].GetCustomAttributes(tAttribute, true);   
            for(int nAttr=0; null == oret && nAttr<attributes.Length; nAttr++)
            {
                // ask the handler if that is what it is looking for
                if( handler.attributeQualifies( attributes[nAttr] as Attribute))
                    oret = assm.CreateInstance( types[nType].FullName);
            }
        }    // for each type
    }    // for each module
    return oret;
}

led mike

[Jost Pedro]

Hi mike, i believe that i miss guided you. I dont want to find which types in an assembly have a custom attribute. I pretend to find which assembly has a specific custom Attribute. So, want happens is I have an assembly that i know for sure that the custom attribute and i the only way that I get it saying that it has that attribute (return true) is comparing their FullName which,i think, is a rude solution to the problem. Tanks for your help. Best Regards Pedro M.