Select only one object with filter

How can select only one object with filter. If I use
selectionset.SelectOnScreen(Codes, Datas), I can select more then one
object, and if I use Utility.GetEntity(Object,PickPoint,Prompt), it dont
have filter. How can do this ???

 

Use GetEntity and test the selected object. If it's the wrong type,
prompt for another selection.

 

But how does one test the entity type of the AcadObject selected?

 

I sed the ObjectName and tested against the AcDbXXXXX of interest.

 

[pre]
If TypeOf Entity Is AcLine Then
...
End If
{/pre]

 

Is there a benifit to doing this "Type of entity" as opposed to "ent.objectname = "...""

??

 

There is no benefit in performance, but search this NG for reasons why
TypeOf should be used instead of ObjectName.

 

I found this:

If TypeOf objBlockSelect Is AcadBlockRef Then
'The variable holds a reference to a block reference
End If

There are two benefits to this syntax. One is that the IDE will assist you
in selecting the type of interface from a dropdown list while you are typing
instead of having to consult a list somewhere. Two is that the code will
actually execute quicker than doing the string comparison.