I am currently a little bit troubled by the following problem. I have a user interface which basically shows a graphic (a canvas made of Lines, Circles, ... these are all WPF objects). Depending on the selection a user makes in the menu, some items get deleted and some get added. So the basic image looks the same, but a few modifications are made.
The user has the possibility to select - say - 10 different "pages" by clicking a Next/Previous Button.
I am using MVVM Light and my ViewModel contains all the items of the graphic (all Lines, ...).
Now I would like to print that graphic to multiple pages. The first page should contain the graphic with changes from page 1, the second page contains the graphic with changes from page 2 and so on. The actual number of pages is dynamic. I track this with a property CurrentPage and a property PagesTotal.
Whenever I push the "Next" button, this causes a command to be executed which will change the variable CurrentPage and also makes sure that the correct items are displayed.
Now I would like to print this but this is where I'm stuck. I dont' mind leaving the MVVM zone and doing some dirty work in code-behind but I would refuse to draw everything again like in the old GDI days.
Any ideas are really welcome.
Create a UserControl containing your display logic (you graphic, for instance). Grab you ViewModel list and project then in UserControls, setting each ViewModel as each UserControl's DataContext.
Force each one to render calling Measure with infinite value and then Arrange with the resulting DesiredHeight and Width. Then follow the procedures to print WPF visuals (link link link).
Essentially, this should be quite simple if and only if your views work independently; i.e. your ViewModel doesn't contain UiElements that are placed into your View.
Simple solution is to basically print your visual root. If need be encapsulate your Views in a user control first.
PrintDialog printDlg = new PrintDialog();
UserControl1 uc = new UserControl1();
printDlg.PrintVisual(uc, "User Control Printing.");
Reference
Alright, I have to admin that I now switched back to doing the printing through code only. I would have really liked doing it "WPF-style" but handling the multiple pages issue was just too much trouble.
Anyway, there is still one issue regarding the printout left but this will be another question.
Related
Is it normal in a WPF app to create a lot of user controls in order to separate concerns that would otherwise be crammed in a single window with a huge XAML hierarchy? I'm finding that I keep making new user controls, even though I don't intend to reuse them, just so that each of my sub-components has a separate task. I'm also giving each of them their own view model, instead of binding things to properties on one master view model.
Is this normal? I feel like from a code cleanliness perspective I'm doing the right thing. But from a WPF perspective, I feel that this can't be right.
For example, let's say you have a list on the left side of the window, and when you select an item, it changes what's displayed on the right side. There are also buttons above your list to manipulate it, adding and deleting items for example. I would be inclined to pull that whole list out as a UserControl, which would contain just the list and the control buttons above it. Then the main window would just include my new control.
Am I going overboard?
I've written a custom panel which displays its children docked either vertically or horizontally, separated by moving splitters in between. Since the Grid panel offers much of this functionality out-of-the-box, I just inherited from it.
To create the layout, upon Loaded is fired I do the following:
1) Read how many children it has and create the appropiate number of rows/colums.
2) Position every existing children in the corresponding row/colum.
3) Create, position and add a GridSplitter for every child.
This approach looks and works fine, but it opens the door to a lot of problems:
Since it's added a GridSplitter for each child, there are twice the number of expected children. If someone added 3 elements to it, Children.Count would return 6.
User could insert/remove things at the wrong place.
It just throws an exception when this Grid is used as the ItemsPanel for an ItemsControl, since in this case WPF (not Silverlight) does not allow direct children manipulation.
These 3 cases are the ones I've already tested, but I'm pretty sure a lot more would arise depending on what the user does with it.
As it turns out, this class must be regarded as 'implementation details', so the real question is, what control should I put in front of the user?
It sounds like it should be a Panel, but I can't control the Children property since it's not virtual, and there's also the ItemsControl which I think could be a good candidate, but I really don't know.
I'd much appreciate any kind of advice or some directions to do this the right way.
Thanks in advance.
You see using just grid you leave yourself with an imperative way of adding items only. As in
myCustomGrid1.AddMyItem(***), Grids simply don't have ItemsSource property. ItemsControls do - so if you need support for declarative items sources i.e. myControl.ItemsSource = {Binding ...} you're going to derive your control from ItemsControl. This is not a two liner - making your ItemsPanel Children writable is a big challange - there's no simple way of doing that.
This is all about a small thing overlooked during the Grid's design - splitters shouldn't have been added to Children collection, as Children are visulaizations of your BOs while spliiters are just formatting elements.
Here's what I would do.
Forget about ItemsSource & items altogether - it's aint worht the hassle. The only way to add/remove items to your control will be AddResiazableItem/RemoveResizbleItem. Calls will add items and splitter (for the middle items), extend the number of rows/cols of your grid depeneding on its orientation, set Grid.Row/Grid.Column attached properties for your visual children. You can keep your actual objects internally to support Orientation change.
If at any stage you'll want to bind your control to IEnumerable source - just create an attached behavior, which will iterate through the items and call AddResiazableItem within a loop.
Cheers.
P.S. To moderators - the editor seems to get broken, lads. I cant see the second item.
P.S.S. Got it fixed after a few tries.
I'm not really sure how to do this in the best MVVM way...
Basically, my main app opens up a search window that shows all records in a TabPanel. Then if a record is double clicked a new tab is opened with that record. Now, I'm trying to keep things MVVM, but I can't for the life of me figure out how to close the gui tabitem when a person deletes the record (why keep it open if the record is gone).
The only way I can figure out how to do it now is to pass the instance of the TabItem as a parameter of the DeleteCommand, which to me seems like a big no-no, but I can't for the life of me figure out how to accomplish this.
If you were going to do this in the true MVVM sense, then double-clicking a record would, behind the scenes, add a record to a collection of records. That record collection is the datasource for the tabs in your control. Simply removing that item from the list (usually an ObservableCollection<T>) would result in the UI updating and the tab being removed.
Which approach are you currently using to show the tab?
Edit (in response to comment):
That is not "true" MVVM. It doesn't matter if the tabs can be more than just records. You should create View Models which abstract those details, then just put your view model instances (RecordViewModel, ReportViewModel, etc) in an observable collection and bind to that. Use datatemplates to render the correct views for each tab's content based on the type of view model the current tab is being bound to.
Josh Smith wrote an amazing article describing how MVVM works. The sample application does something very similar to what you want to do.
The application displays a TabControl which displays 1 or more workspaces. The workspace area displays two different kinds of items. The tab items are closable. Take a look, I'm sure this will solve your problem.
WPF Apps With The Model-View-ViewModel Design Pattern
I need to create a WPF application which is maximized and which rotates amongst about 10 different screens. Each screen will take the entire area and show different content.
I already know how to maximize the window with
My question is what is best to put inside that window to achieve what I want?
Ideally I'd be able to have 10 different .xaml files and I just load one after the other to take the entire screen. I'm not sure the best approach for accomplishing this in WPF.
Thank you!
One quick way to do this is to use WPF's built in page navigation. By making your root window a NavigationWindow and each view a class derived from Page (similar to work with to a UserControl or Window) you can just set the NavigationWindow.Source to a relative URI that points to the page you want to show (like a web browser) and simply switch it as needed.
This sounds like a classic MVVM application, which is simply too much to put into detail here. Google MVVM or Model-View-ViewModel, or pick up the book Advanced MVVM by Josh Smith (widely regarded as an expert in such things).
However, this is basically what you are going to have:
One class, the ViewModel, is an abstraction of the data that you need to bind to
Your data Model
A View for each thing you want to show. A View is simply something that holds your UI, be it a DataTemplate or a UserControl. Each View is bound to the ViewModel
The Views are the things that will "rotate" (although rotate in WPF implies animation and/or transformation). How you switch between them is up to you, although it sounds almost like something that would be done with a DispatcherTimer and animation (i.e. like fading between pictures in a slideshow).
This question is really too broad for this forum - you will need to do quite a bit of research on WPF fundamentals before proceeding. Again, MVVM is a good direction to start.
EDIT: Something More Lowbrow, per OP Request
This is probably as simple was you can make it (and still create separate XAML files for each piece of content):
First, create 10 UserControls (XAML files) for the stuff you want to show.
Next, add an instance of each of these user controls to your main window. Set the Visibility of each of these to Collapsed, except the first one to show.
Put a "Next" button on the main window.
In the code-behind, handle the Click event for the Next button. In there, keep track of which UserControl is visible, by name. Set the one that is currently visible to Visibility.Collapsed, and set the next one that is supposed to be visible to Visibility.Visible.
This is certainly an ugly solution, and not very WPF-ish, but it will get the job done.
In order to make a convenient UI for an .Net 2.0 Winforms application I am working on, I have need for a control that I'm pretty sure goes beyond the "out of the box" behavior of any standard control. A mock-up of what I'm trying to achieve follows:
Mock up http://www.claware.com/images/temp/mockup.png
Essentially, this part of the application attempts to parse words into syllables from tribal languages (no dictionary to refer to; any and all unicode characters are possible.) By the time the user gets this far, he has already defined the vowels / consonants in his language and some other configuration. There is then an iterative process of (1) the application guesses which syllables exist in the language based on some rules, (2) the user refines the guesses, selecting the correct parsings or manually parsing a word, (3) the application "learns" from the user's feedback and makes smarter guesses, (4) repeat until the data is "good enough" to move on.
The control needs to present each word (the grey headers), then all the syllable break guesses (the white areas with dots separating the parts of words.) There is also a way to manually enter a parsing, which will display a text area and save button (at the bottom of the mockup.) When the user hovers over a guess, the background changes and "accept / reject" buttons appear. Clicking on the accept, or entering a manual parsing, removes the entire word from the list. Clicking the reject button removes just that item.
I'm by no means 100% sold on the formatting I have above, but I think you can get a general idea of the types of formatting and functional control I need. The control will also scroll vertically--there may be thousands of words initially.
My question for you experienced WinForms developers is: where to start? I would really, really like to stay within the .Net core framework and extend an existing control as opposed to a third-party control. (At the risk of starting a religious war: yes, I suffer from NIH-syndrome, but it's a conscious decision based on a lot of quick-fix solutions but long-term problems with 3rd party controls.) Where can I get the most "bang for my bucK" and the least reinventing the wheel? ListView? ListBox? ScrollableControl? Do I need to go all the way back to Control and paint everything manually? I appreciate any help that could be provided!
[Edit] Thanks everyone for the ideas. It seems like the most elegant solution for my purposes is to create a custom control consisting of a FlowLayoutPanel and a VScrollBar. The FlowLayoutPanel can contain instances of the custom controls used for each word. But the FlowLayoutPanel is virtual, i.e. it only contains those instances which are visible (and some "just out of scroll"). The VScrollBar events determine what needs to be loaded. A bit of code to write, but isn't too bad and seems to work well.
I would look at the TableLayoutPanel and FlowLayoutPanel controls. These will let you organize a series of controls with moderate ease in a vertical fashion. I would then create a UserControl that consists of a label and 2 buttons. The UserControl will expose properties like Text and events that are exposed for the button clicks.. For each entry in the list, you will create an instance of the UserControl, assign the text value, and handle the click events. The instance will be placed in the Table/Flow panel in the correct order. Both of those layout panels do allow for inserting items between other items so you can add/remove items from the list dynamically.
Edit:
Given the length of what you are trying to render, I would consider using the DataGridView and do some custom rendering to make it perform how you want it to work. Using the rendering events of the DGV you can merge columns, change background colors (like highlighting the dark gray lines), turn on/off the buttons, and handle changing the grid into edit mode for your rows to allow modification or inserting of new values. This method would easily handle large datasets and you could bind directly to them very easily.
Well, this certainly looks like a candidate for a custom component that you should be creating yourself. You can create this using standard .Net drawing commands along with a text-box, and a regular button control.
Now you want to find out where to start.
Create a Windows Forms Control Library project.
Drop in the textbox and the button control.
The panel drawing code should preferably be done by code. This can be done using the regular GDI+ commands.
Edit:
Here's another idea, and one that I've practically used in my own project with great success.
You could use a web-browser control in the app, and show your data as html. You could update the source of the web-browser control based on the input in the textbox, and clicking on the links in the web browser control will give you the event that you can trap to do some action. Your CSS will work.
I used this technique to build the 'desktop' in an app I made called 'Correct Accounting Software'. People loved the desktop so much that it is one of the best loved features of the app.
Here's how I would do it:
Create a custom control. In this custom control, have a ListBox atop a LinkButton, and when the LinkButton is clicked you can make it give way to a TextBox. The ListBoxes will have the top row unselectable... you can probably get the rest from there. When you get your list of words, fill a Scrollable of some kind with one control for each word:
(foreach String word in words){
myScrollable.add(new MyComponent(word));
}
From there, I'm not sure what you want to do with the boxes or the data, but that's my initial idea on the UI setup.
Use the WebBrowser control and generate the HTML markup into it using DocumentStream or DocumentText.