I am trying to build a generic interface that can accept a List of objects and then based on the users selection of how they want to view the objects will select different ways of display the object. Currently, the user has a dropdown that allows them to choose the view type such as "Details, Previews, etc" much like explorer and then based off the selection the display should change. My first attempt at this was to create UserControls that will accept the bound object and display it, however I dont know how to convert my listitems into the user controls. My question is, is should I be using IValueConverter to convert the listitem into the type of user control I want to display, or should I be using DataTemplates and a TemplateSelector to define my different views?
Why not just use ListView and GridView? Your use case is exactly why they're there.
MSDN has a nice little sample for how to switch views in a ListView at runtime right here.
Related
I have a listbox that is databound to a List with a bindingsource, what I would like to obtain is that the listbox only shows certain object properties like for example firstName,lastName instead of firstName,lastName,Address,Country,...
How could I manage this?
I'm using winforms.
What about create another type which will be your exact view model and use list of this type?
my last project was a big project in winforms,and i was told that the data bound controls effectively reduce the overall performance of the application.
so the whole group had to work programmatically when adding data to a control,let it be datagrid,combo box,or any other windows control.
i would suggest you do the same too,Adding data to your Controls using code.that way you also decide what you want your clients to see and whatnot.
i would also suggest you take a look here :
how-might-i-add-an-item-to-a-listbox
I apologize for the crappy title, I wasn't quite sure how to summarize what I'm trying to do.
My scenario:
I am refactoring an existing WinForms application to WPF and MVVM. I'm currently working on a module that provides search functionality for a database comprised of many different tables such as Contact, User, Case, Product, etc. In code-behind there are classes which provide an Object for each. I have written wrapper classes for each of the searchable table Objects that expose only the properties a user would want/need to see in the search results for each type of Object, for binding to a DataGrid.
Once these search results exist, they need to be displayed in a combination of Tab Controls and Data Grids, like so:
Because of some use cases, I need to be able to create an individual display Tab+DataGrid for the results of every single search that is performed. I cannot have a single tab for each type of search that is shown/hidden as needed.
I'm not sure how to proceed from where I currently am to the goal pictured and described above. Thanks for any help anyone can provide.
Not sure I entirely understand your question, but it looks to me that it might be a candidate for datatemplateselector.
Basically, you use an ItemsControl bound to your result collection and then - using a datatemplateselector - you swap in the appropriate template to display the item based upon a code inspection.
That will let you present all the results in a single list.
If you want to display your results in a tabs, I would present a collection of each result type in your viewmodel. So you have a Users collection and a seperate Products collection. Then you can bind individual data grids to each template.
If you want to then hide the tabs when no results are present, add a data trigger using the expression.interactivity namespace to trigger the visibility of each tab page based on its respective collection count.
One more thing, if you want to create tab items dynamically, i.e. One tab for each search - the tab control has an ItemSource property. If you group each search result into an object an expose an observable collection of that object, you can bind that to your tab control and have it create tab items for each search result. Just make that object contain a collection of actual results and you should be able to create a itemscontrol as mentioned here already.
Sorry if this appears a bit of a mind dump, but like I said - not sure if I entirely get the question :)
Rather then chuck a load of code snippets in, there a plenty of samples just a google away if anything sounds helpful.
So it seems like what I want to do should be straightforward, but I haven't been able to find a way to do it...
I need to display a list of objects that represent custom elements for entering data. Exactly how each object is displayed depends on the parameters of the object - so it could be a grid containing a name, description, and text box. It could be a grid with a couple labels and a dropdown. It could be an expander that contains multiple sub-objects. It could be something new that hasn't been built yet (so it needs to be extensible). Right now, I am populating this list by creating the FrameworkElement for each object and then adding it to a Grid by hand.
I would like to switch to keeping my objects in an ObservableCollection, and then binding that collection to a ListBox (or similar). That way, when new objects are added or removed from the list, the UI would automatically update itself accordingly. What I can't figure out is, is there a way to point it to my C# method for creating the custom-configured FrameworkElement for each object, so that when new objects are added the appropriate elements will be added to the UI?
Well, you're on the right track as far as wanting to use an ObservableCollection<T> and a ListBox control. Though, I'd venture to say you might want to simply use an ItemsControl since you probably don't care about selecting a particular item, but merely displaying an enumeration of items, and the ListBox would allow you to actually select one of those items.
Your problem is that you want each item in the list to display differently depending on certain criteria. For this you'll want to look at the DataTemplate and DataTemplateSelector classes.
Basically, a DataTemplate is a way of saying "I want my item to look like this.", and a DataTemplateSelector is a way of saying "I want to select this specific DataTemplate based on this criteria."
Here are a few examples on how to use the DataTemplate/DataTemplateSelector classes:
http://tech.pro/tutorial/807/wpf-tutorial-how-to-use-a-datatemplateselector
http://mikestedman.blogspot.com/2009/04/datatemplateselector.html
http://wpftutorial.net/DataTemplates.html
Seperating the presentation from the model is always a good idea. It seems like you are on the right track.
Foreach object type, you should create a DataTemplate and then use ItemTemplateSelector to select the correct template for each object type.
Good luck
Say you have a xaml page that takes two inputs such as DATE and some TEXT value and displays the result on a DataGrid, its easy to have a class with with 3 properties of dataTypes DateTime, string and some Collection and implement the same in MVVM.
I have a xaml page with a DataGrid and few input controls(like textbox or datepicker) generated dynamically based on a certain criteria. I want to implement this in a MVVM pattern but not sure how to go about. Any pointers will be helpful.
In my experience, MVVM is not answer for all presentation scenarios, sometimes you just have to use codebehind or build custom control. I would suggest here building custom control that takes (binds with dependency property) object or list of objects, and generates controls (text boxes with input validation/verification, for ints, doubles, date picker, etc), and binds given object to them. In the end you will have one smart control that takes object and renders input fields, and binds to them. Your VM class would just expose object or list of objects.
It is always good to separate the view and the model; however this cannot always be done with simple data binding of simple types.
I would be looking at something like a custom control that could databind to a list of {name, value, spec} pairs when the “spec” is the logical type of control to use.
Thinking about it; that is like what a property grid does if you pass it a custom collection of property descriptors….
Devexpess has a “vertical grid” that may help, also look at 3rd party property grids.
If have a control that acts like a record selector from a database, say, for example, customers.
The control must act in certain ways allowing the user to type the name, the alias or the code of the customer, and the control will select the correct one, or offer a list of possible candidates, and other behaviors.
I have tried to inherit from ComboBox, but there are some ComboBox behaviors that make it difficult or impossible to do what I want, so I'm better starting from scratch, with a TextBox and Button.
The questions are:
Do you know some open-source component so I don't have to start from zero?
Have you already done something like this and want to share methodologies or tips?
Am I good with a TextBox, a Button and a PopUp control?
Try this control from CodeProject: A Reusable WPF Autocomplete TextBox
It allows you to specify a source list, and a custom filter. In your custom filter you can select to show only those records that have a name, alias or code that fit the text entered, and the user will have a list of filtered options displayed to them.