Develop Reference

Determining If Element is In Dependent View (Revit API)

I'm trying to write a macro for Revit 2020 and 2018 in C#. So far, I have written a program that takes selected elements and filters them if they are within a particular view. However, issues arise when using dependent views because when selecting all elements in a view, it also selects everything in the other dependent views. I don't want this to happen. I'd like to find a way of filtering elements that are only within one particular dependent view.
I've tried having the user select from all available views, but it still treats a dependent view as though it were the larger superview.
The easiest way to solve this would be if there were a way to check membership to a particular view. However, I haven't figured out how to do this. Any suggestions?

Copied from Tray Gates' answer to check if the parameter exist - check if the view is dependent or callout:
You can check to see if a view is a dependent view using GetPrimaryViewId from a view element.
If the result is -1, it is NOT a dependent view.
If it is any other integer, it is a dependent.
Here is an example:
var views = new FilteredElementCollector(doc)
.OfClass(typeof(View));
foreach (View view in views)
{
ElementId parentId = view.GetPrimaryViewId();
if (parentId.IntegerValue == -1 && !view.IsTemplate)
{
// View is NOT a dependent
}
else if (parentId.IntegerValue != -1 && !view.IsTemplate)
{
// View is dependent
}
}
Note that -1 is shorthand for ElementId.InvalidElementId.
Later: I see that you asked the same question in the Revit API forum thread on Determining If Element is in Dependent View, received other answers there, and discovered that your need is in fact different and more complicated...

How can I hold a collection of strings to post back?

From my controller I send a ViewModel with a collection of strings to be used in a <select> tag like so...
Controller:
var model = new InviteViewModel
{
SelectItems = new SelectViewModel
{
Companies = _companyRepository.GetCompanyNames()
}
};
Razor View:
<select class="form-control company_select" asp-for="Company" asp-items="#(new SelectList(Model.SelectItems.Companies))"></select>
This works perfectly and will display all the items in the drop down box. However when I go to submit the form the Companies object will be null and when the View is sent back I get a null reference exception. Normally I would create a hidden <input> tag to hold the value, but how can I do this with a collection?

There are so many ways to do this.
It seems like you may have a fundamental misunderstanding of the disconnect between Razor and html. Razor executes server side, and its result is simply a string that gets written to the response stream. Once written, razor's scope is gone and cannot hold data.
One option would be to store the collection in the application cache or session cache with a guid as the dictionary key, and then use a hidden input for the cache key. When the view is being recreated you would then have access to the server and could gather the collection.
This makes the assumption that the collection hasn't changed during the time the view was active, which given some user habits could have been a long time. There should also be some sort of metrics used when caching to invalidate old data, if this is the route you take.
Another option is to simply regenerate the collection from wherever (database?) it came from.
Lastly, you mention that the view is being returned with the empty collection, are you returning a view from a post method? That is bad practice. Look up the "post-redirect-get pattern" for why and how to avoid it.

Is it possible to "inject" updates into a Knockout ViewModel?

I'm currently looking for a solution to my issue: In our ASP.NET MVC application there are pages that are used for realtime data visualization of industrial devices. When the page gets loaded, a loading icon is shown while I fetch the viewmodel data with the current values for all the datapoints from a database. That works quite well, but it is static, by which I mean that the values don't change on the page after it finished loading. The web application itself uses a TCP listener that receives messages with values from the devices. These messages (which basically consist of a device id, a datapoint id and the value) don't arrive in fixed intervals but event-based, e.g. when a temperature value changes 0.5 K up or down.
On my page I have some graphical widgets like gauges and many other elements that correctly show the values from the initial data that gets loaded on the page load. They are bound to the Knockout viewmodel.
The problem is this: whenever a new value arrives on the server, I want to show it on the page without the need for a reload. I definitely don't want to re-transmit the whole viewmodel with some hundred datapoints on every message that arrives on the server (appr. 1 to 15 per second). In order to achieve that, I implemented the SignalR framework, which really works great. With that mechanism I now receive the new value in the client window (that means, I receive it in Javascript and now have a value object like described below).
What I need now is this: as every viewmodel gets built dynamically, they are all different. The object and properties tree is not the same for two devices, so each of them can have varying levels of subobjects. The only thing that is the same is the structure of the object that actually holds the value for each datapoint: it always consists of the aforementioned device id, the datapoint id and the value.
I need a way to update the double-type value inside the value object within the viewmodel whose device id and datapoint id match the newly arrived value message (that also consists of these two address-like ID's and the value).
I hope I got the idea across. Is there a way to do this? What would be the best practice for such a mechanism? I recently switched to Knockout-MVC (kMVC nuget package), but I'd also go back to "pure" Knockout.js and some additional scripting if that helps.
Thanks for your help and recommendations!

http://nthdegree.azurewebsites.net/mvvm-2/
Here is an article speaking to the Knockout mapping plugin
The general idea is that you should have your view model code which loads your model.
You would bind up your view model which will have a property you load from the server with an ajax call (see bottom of article).
You then just update the model with the result with
ko.mapping.fromJS(newData, mapping, modelToUpdate)
var mapping = {}; //define your mapping (see documentation or blog post)
function ViewModel(){
var self = this;
self.model = ko.mapping.fromJS({}, mapping);
self.hub = $.connection.myHub();
self.hub.client.updateModel = function(data){
ko.mapping.fromJS(data, mapping, self.model);
};
self.hub.start().done(function(){
//you could either make a call or have the "OnConnected" method trigger an 'updateModel'
});
}

ViewModel properties when linked to a DOM element allows editing which is actually updating the data in the KO observable array. Is it possible for you to change the "graphical widget"'s value (assuming that it is using some property to maintain height and width) using the IDs which you said are consistent?
I have not tested; the other option is to use KO foreach loop and update the related value.

Displaying results in View linq to sql mvc 4

I have been reading and reading , and I can't seem to get this to work at all. I am very very new to asp.net MVC - after all the tutorials I read I finally got this much accomplished.
public class EventsController : Controller
{
private EventsDBDataContext db = new EventsDBDataContext();
public ActionResult Index()
{
var a = (from x in db.tblEvents
where x.StartDate >= DateTime.Now
select x).Take(20).ToList();
return View(a);
}
}
This is successfully finding 20 rows (like it is supposed to). Now how do I display these in the view ?? Does it have to be a strongly typed view?? It doesn't seem like it should have to be... I have tried both , I tried typing a whole view, but for now it would be nice to just get one property of tblEvents to show up in the view. This is not working, I have tried many many variations.
#{foreach( var item in Model){
#Html.DisplayFor( item.ID)
}
}
How do I get the results from the controller displayed in the view? Just the ID is good for now - I can go from there.

The problem is that your View doesn't know what type your Model is. Use the #model syntax to define the type of your model.
#model List<YourEventClass>
#foreach( var item in Model )
{
#item.ID<br />
}
See i.e. here for more information

from the root of the web project you should have a directory called Views. Within the views folder create a new folder named Events. In the Events folder create a razor view named Index. put your markup and template code in this file.
You are correct, views do not need to be strongly typed. I find it's a good idea to do so because it provides another compile time check, but it's not required.
when you run the application you will navigate from the root (typically home/index) to Events/Index. there you should see the list of 20 items rendered in the view.

I guess you can not do something like this:
#{foreach( var item in Model){
#Html.DisplayFor(modelItem => item.ID)
}
unless the view knows what Type Model is returned as (still seems weird that .Net can't figure that out on its own. So I fixed the problem and got the ID displayed properly by adding this to the View.
#model IEnumerable<GetEvents.Models.tblEvent>
This works fine for this example - I am returning one table , so the Model type is just the class for the table. But this doesn't seem right - what if I wanted to query and join tables then what would the Model Type be?? Adding this fixed my problem , but if someone has a better answer for this then I will accept that.

How do I persist a value accross views

Completely new to asp.net mvc... completely new to web apps so bear with me...
Lets say I have an Action on a controller that requires a specific piece of information, say an int Id value.
A view is rendered from this Action. This view contains a button which will take the user off to a new Action on another Controller.
On the view of this second Action, there is a link that will send them back to the original Action on the Controller. Obviously, I've lost the original Id value and therefore the information I need to render my original view. What do I need to be looking into to solve this? Are there techniques/patterns that could be used to help?
I know I can keep passing the value around but if the other controller doesn't actually need this value it seems wasteful. I think I'm probably approaching the problem the wrong way to be honest. Any help appreciated.

I know I can keep passing the value
around but if the other controller
doesn't actually need this value it
seems wasteful.
But the second controller does need the id to function properly - as you've said, it needs the id to render the return link. Passing it around is the right thing to do.

There are many ways you can achieve this. Some of them are :
You can keep the value in the Query String.
If navigation from Action-1 to Action-2 is done via posting a form, you can send the value with a hidden input tag. Eg : <input type="hidden" name="n" value="v" />
You can use TempData to persist information between two requests (though it doesn't look like this is a good solution for your case)
Without knowing what exactly you are trying to do, it's hard to know best solution.