.NET

[#1]

As you know,the managed wrapper class cannot use the conditional selectionset.But with DOTNETARX,you can solve this problem just as the following(select line and circle):
TypedValue[] values={
new TypedValue(-4," new TypedValue(0,"Circle"),
new TypedValue(0,"Line"),
new TypedValue(-4,"or>"),
};
ObjectIdCollection ids= Tools.GetSelection(values);
For more information about DOTNETARX,you can read this article:
http://www.codeproject.com/useritems/dotnetarx.asp

[#2]

Hello, how to get that magic thing, DOTNETARX by name?

[#3]

You can find it on:
http://www.codeproject.com/useritems/dotnetarxsample.asp