Connect Version 13 C# Programming - ScanCriteria

Donna Rodrick said:

I am having issues with ScanCriteria

As Jan commented, you haven't told us your problem.  Here's an article about Model Scanning and Enumeration using .NET for MicroStation CONNECT.  Examples are provided.

 List elementTypes = new List
        {
            MSElementType.Text
        };
        scanC.AddElementTypes(elementTypes);
        elementTypes.Clear();

.NET passes objects by reference.  You set the scanner element types and immediately clear the list.  I would be inclined to remove elementTypes.Clear().  You do similar with element classes.

Hi Jon,

Jon Summers said:

Here's an article about Model Scanning and Enumeration using .NET for MicroStation CONNECT.

the part about using ModelElementsCollection is misleading a bit: There is (nearly never) reason to obtain Enumerator from IEnumerable<T> collection explicitly. In the discussed situation it's bad practice, because instead of simple foreach enumeration it leads to more complex code. And the performance of both (foreach and while) is usually nearly the same for List enumerables.

Minor comment is that to use "model_" as a variable name is against C# naming conventions. And even when I am aware the conventions are not mandatory rules and everybody can define own ones, for C# these standards are well defined and followed generally (and can be checked by different assistants like StyleCop etc.). So to use anything else (e.g. to apply C/C++ naming styles to NET world as many develoeprs do)  in contraproductive at the end.

Regards,

  Jan

Hi Jan,

Thank you so much for your help!  I like the ElementPropertiesGetter, I wrote my code using GetDisplayParameters() to get class information.  I am changing it to the ElementPropertiesGetter.

I truly appreciate the kindness of this group.

Donna

Hi Donna,

Donna Rodrick said:

Thank you so much for your help!

It's my pleasure ... and it did not require too much effort as I reused a code snippet from my (still growing) library of "try to understand how this piece of API works" code :-)

To use the simple iteration is recommended by Bentley, such discussion is somewhere in this forum history.

To use ScanCriterias is fine and more convenient for people using ScanCriteria concept in the past, but it's slower (I did some tests, but I do not remember exact results). When there are a lot of conditions and filters, the iteration could be implemented using a complex code and the performance is similar to ScanCriteria, but an advantage is it's possible to optimize exactly based on an application priorities.

Donna Rodrick said:

I like the ElementPropertiesGetter

ElementPropertiesGetter and ElementPropertiesSetter are primary ways how to access an element properties.

Donna Rodrick said:

I truly appreciate the kindness of this group.

Thanks :-) ... I am aware of we (me including) are not always nice, but when anybody provides own code (so it's clear he tries to do something and it's not "write code for me"), I am sure he will receive some responses from the community.

With regards,

  Jan

Jan Šlegr said:

the part about using ModelElementsCollection is misleading a bit: There is (nearly never) reason to obtain Enumerator from IEnumerable<T> collection explicitly

You'd better inform whoever at Bentley Systems wrote the SampleECProvider delivered with the SDK.

Bentley.DgnPlatformNET.ModelElementsCollection elementsCollection = 
    element.DgnModel.GetGraphicElements ();
Bentley.DgnPlatformNET.ModelElementsEnumerator elementEnumerator = 
    (Bentley.DgnPlatformNET.ModelElementsEnumerator)(elementsCollection.GetEnumerator ());
Bentley.DgnPlatformNET.Elements.Element currentElement = null;
while (elementEnumerator.MoveNext())
{
  currentElement = elementEnumerator.Current;
  if (!SupportsElement (currentElement))
    continue; // only process elements that are supported.
   …
}

Jan Šlegr said:

the part about using ModelElementsCollection is misleading a bit: There is (nearly never) reason to obtain Enumerator from IEnumerable<T> collection explicitly

You'd better inform whoever at Bentley Systems wrote the SampleECProvider delivered with the SDK.

Bentley.DgnPlatformNET.ModelElementsCollection elementsCollection = 
    element.DgnModel.GetGraphicElements ();
Bentley.DgnPlatformNET.ModelElementsEnumerator elementEnumerator = 
    (Bentley.DgnPlatformNET.ModelElementsEnumerator)(elementsCollection.GetEnumerator ());
Bentley.DgnPlatformNET.Elements.Element currentElement = null;
while (elementEnumerator.MoveNext())
{
  currentElement = elementEnumerator.Current;
  if (!SupportsElement (currentElement))
    continue; // only process elements that are supported.
   …
}

Oh ... who wrote this? And why?

Really, thanks for this comment, I have had not many reasons to study NET examples yet, so I am surprised, because in my opinion, the code is just bad. But of course, maybe I am wrong, but in such case I would like to know why this implementation with less readable code, is used.

All tests I recall, done using NET 4.x, show that foreach is faster for small collections and very slightly slower for large collections than while. To implement proper element evaluation will cause probably bigger slowness than the difference. But it would be niec to do some benchmarking, because there is native code behind NET wrappers, so the results can be different in case of MicroStation API.

Regards,

  Jan