Before I begin here is a reference to how I implemented a template selector with Silverlight.
http://geekswithblogs.net/tkokke/archive/2009/09/28/datatemplateselector-in-silverlight.aspx
Everything works great. But the solution just doesn't work in blends making things more difficult to visualize overall. Is the correct work flow to just create a UserControl from the contents and embed it inside the Resource Dictionary to make it blendable, or is there a better way to do this?
Either way, I'm asking this question and posting the Template Selector solution at the same time, because I found it useful. Better solutions are very much welcome.
fyi.. sl4,.net4, latest blends.. all the new toys.. using mvvm light(little relevance).
I would recommend you go with the the following kind of implementation: DataTemplateSelector on CodeProject.
The drawback of the link you posted is that the location and name of the templates are hard-coded in the ContentControl's implementation. With the approach provided in the article I link to, the data templates are accessed in-line, or by regular {StaticResource} references (which means more flexibility), and on top of that, Blend knows what to do with that.
Related
I’ve been having issues with the TreeView in WPF. This control makes it very hard to access the TreeViewItems it’s showing.
On several occasions I have worked around the need to access a TreeViewItem, for example I’ve accepted the fact that I’m not supposed to access a node’s parent via TreeView (and am supposed to instead keep track of the parent myself). I’ve been doing this for two reasons: first, it’s obviously extremely hard to get at the TreeViewItems, and secondly, I’ve been told that it’s hard because I’m not supposed to need them if I do things right.
However, this time I really see no way around this.
Basically, all I want is, given one of my viewmodel instances, scroll the tree view to it. This is trivial if I could just get the corresponding TreeViewItem.
Am I doing things wrong again by trying to get at the TreeViewItem, or would that be the right approach?
Take a look at Simplifying the WPF TreeView by Using the ViewModel Pattern article by Josh Smith. I hope it helps.
Admittedly this is not straightforward but you can probably still do this while keeping a separation which does not require you to access the TreeViewItems knowingly. The essence in WPF is binding as already noted by Kent Boogaart in your other question, here however you need to somehow deal with events. Your view-model needs to fire a BringIntoView event of its own while the view needs to react.
The easiest method might be to add a EventSetter on Loaded to make the TreeViewItems subscribe to said event on their DataContext which should be your view-model (if it isn't you can wait for DataContextChanged).
No, I dont see in what way accessing the items of a treeview is wrong.
I think the difficulties you are encountering are because you aren't seeing the treeview as it should be.
A leaf has a parent, but no children.
A node can have a parent, and can have children.
A node without a parent is a root.
Based on these principles (SourceMaking Composite pattern) you should be able to do whatever you want using recursivity. (in both XAML and code)
I’ve come to the conclusion that it can’t be altogether wrong. The first piece of evidence comes from Bea Stollnitz’s post about ListView: if one of the WPF developers explains how this might be done, it can’t be that wrong.
The other piece of evidence comes from this highly-voted question/answer: MVVM madness. MVVM undoubtedly has its benefits, but sometimes the cost of following MVVM is so high that it’s just silly following through with it, especially in a small one-man application. Do you really want to expose IsSelected and IsExpanded the way you’re supposed to?
As a result, I felt justified to try and figure out how to expose the TreeViewItem corresponding to an item with less effort from the developer, under the assumption that they will never need the more advanced features that resulted in TreeViewItems being this hard to access (like displaying the same ViewModels in multiple different controls... how often have you needed that!...)
I posted the result of this effort as an answer on another question.
it seems there are a number of approaches on how to implement multiple languages in a WPF application. But I would like some more information about what method I should be using with the following requirements:
It's a PRISM application, so a number of independent modules (assemblies) working together. I would like that each assembly has its own translations of UI elements.
I need a simple approach, no tools needed to generate stuff
Should still be able to use blend to design the UI
Optionally be able to switch language without restarting the application (not a dealbreaker)
Can someone advice me on how to achieve this?
Thanks!
A common approach is to bind the text property of your textblocks / labels etc.. to some property on a statically defined localization resource:
<Label Content="{Binding Source={x:Static loc:LanguageContext.Instance},
Path=Dictionary, Mode=OneWay,
Converter={StaticResource languageConverter},
ConverterParameter=TextId}" />
i.e. LanguageContext.Instance exposes a dictionary via a property Dictionary, the Converter uses the given ConverterParameter to look up the text identified via TextId.
This is a cumbersome approach, and will not fulfil all your requirements.
A better method is to defined your own markup extension to perform this sort of logic. There are a couple of solutions I have seen on the web, this high rated codeproject article:
http://www.codeproject.com/KB/WPF/realtime_multilingual.aspx
And a similar solution here that provides Blend, on-the-fly language changes, so is probably a good choice for you:
http://blogs.microsoft.co.il/blogs/tomershamam/archive/2007/10/30/wpf-localization-on-the-fly-language-selection.aspx
With the above example you define an attached property which identifies the key of the translated item, and use the Translate markup extension to identify the properties which are translated.
NOTE: it is not just text which is being translated here, often you have to change colors / graphics etc ...
Meanwhile I found an open source project that works really well: http://wpflocalizeextension.codeplex.com. It's just adding a reference to the dll, adding the resources with translations, and using it in XAML. It worked in 5 minutes. I can add multiple resources to individual modules; and it works fine in visual studio designer and blend. And, locale can be changed on the fly. Meets my requirements :)
I am new to Silverlight and have a requirement to highlight (or change font color) all words and phrases wtihin a TextBox that match a list of words/phrases. At first I though this would be easy, but the more I look into it, the more confused I get.
My goal is to write something reusable so I can also apply the logic to a RadGridView later. I've seen a few examples of stuff close to what I need, but it's beyond my Silverlight level at this point.
I want to write this myself to get a better understanding of how some of the Silverlight internals work. Can someone point me in the right direction of where to start on something like this? Should this be implemented in a control? Should I use a behavior? I'm using Silverlight 4.
Once I know where to start, I am sure I can get this done - with some help from you guys of course ;-)
Thanks,
-Scott
How about using the RadRichTextBox (I assume you have a licence for it as you mentionned the RadGridView)?
There's also a good sample project on Telerik forum that is doing exactly what you want to do.
I'm currently evaluating QtQuick (Qt User Interface Creation Kit) which will be released as part of Qt 4.7. QML is the JavaScript-based declarative language behind QtQuick.
It seems to be a very powerful concept, but I'm wondering if anybody that's made extensive use of other, more mature declarative-UI languages like XAML in WPF or Silverlight can give any insight into the real-world benefits that can be gained from this style of programming. Various advantages are often cited:
Speed of development
Forces separation between presentation and logic
Better integration between coders and designers
UI changes don't require re-compilation
Also, are there any downsides? A few potential areas of concern spring to mind:
Execution speed
Memory usage
Added complexity
Are there any other considerations that should be taken into account?
(Updated)
The misconception with XAML is that it's not compiled. It is indeed compiled down to BAML a binary pre-tokenized XAML. Apparently there was a IL compiled version of XAML too called CAML. The OP pointed me to this good article explaining what XAML/BAML and CAML are.
Anyway, to the question why to use it:
XAML is simply a Serialization Format for C# objects that it is particularly well suited to describe hierarchical object structures, like found in WPF GUIs.
What WPF helps you do is write less boring C# code like this:
var grid = new Grid();
grid.Content.add(new TextBlock() {Text = "Hello"});
grid.Content.add(new TextBlock() {Text = "World"});
and just express it in a more readable way like this:
<Grid>
<TextBlock Text="Hello">
<TextBlock Text="World">
</Grid>
Since WPF object nesting (putting stuff inside other objects) can get very deep, WPF makes it much easier to read than the resulting C# code.
As for separation of concerns: XAML helps here too since it does only allow you to express objects and their relationships/properties, rather than logic. That forces you to separate logic from UI layout. The MVVM Pattern is very well suited for this task and allows for eay testability and interchangeable Views.
Added complexity in XAML can be also easily dismissed because the same code in C# gets easily more complex than the XAML markup.
I can't give you any insight into QTQuick though. Sorry
QtQuick is extensible via C++ plugins, actually what the Qt guys recomment is that you do the UI, Animations, Transitions etc in QtQuick/QML while all of your business logic is in C++/Qt. So this way you get the best of both worlds, you can debug your C++ code like you usually do, while at the same time making UIs becomes effortless and extremely easy.
Also another important think about QtQuick/XAML is that they are hardware accelerated, so for example you can get pretty good fps without any effort. So they are not slow at all for what they set out to accomplish.
It saves time, soo much time. I did a UI with code in 3 days, did the same in QML in 2 hours.
The point of declarative coding, i.e. WPF or QTQuick is to provide a separation between the developer and presumably the artist that is implementing the visual aspects of your application. With regards to WPF, I find that debugging gets to be a bit harder. As we speak, I am compiling the latest QT to look at QTQuick. (It takes a long time and I have time to look at stackoverflow :-) ) So, I don't have an opinion on that yet.
QML/XAML are:
Great for MVVM pattern
Hardware accelerated (QML with using OpenGL for Windows, MAC, Linux and Phone OSes... XAML with using DirectX for Windows and its phone version)
Closer to artists
You can create a GREAT and NICE UI using XAML/QML
Easier UI implementation
Nice animation is possible
In XAML, usually you can create a Silverlight version of your application just with a little changes
In XAML there is some great features such as Template, Trigger (DataTrigger, Trigger, EventTrigger), Binding (in any side and also both side together), Resource, Commands, DependencyProperty and Notifiable Properties.
But please note in XAML: (I am a XAML programmer, therefore i have not points for QML)
XAML debugging is not possible
For any change in XAML, all program must be recompile
Be more careful for performance. For example if you use much many RoutedCommands in XAML, your application will be unusable!
In XAML, some feature not works as expected. There is unfortunately some tricks. (It should be clear... should works as expected... isn't it? )
Be careful for some similar namespaces like BitmapEffect and Effect. There is different features and costs. (e.g. BitmapEffect has some effects with software render and Effect has some effect with hardware render)
In real world, artists could not use WPF as Flash (at least with good performance).
Some features works on special places. For example DataTrigger works just in Style tag not in Resource section.
There is some weaknesses in XAML. Some examples: there is not any sequential animation... you cannot do any calculation in XAML (you must write a converter in C# even for a liiiittle work! JavaSript is a great replacement in QML)... some attributes are duplicate. e.g. x:Name and Name... Controlling View from ViewModel is not clear. e.g. closing View from ViewModel (you need some CodeBehind)
Tooooooo much run-time errors. If you use some tags in bad place it will notice you for syntax error, but many of errors occurs just in the run-time. e.g. if i target Background property (instead of Background.Color) for ColorAnimation, it will compile successfully, but in running animation... BUMP... runtime error!!! in such case on Expression Blend, application will crash!!!
I'm looking for something like a ContainerUIElement3D which supports the ItemsSource property and an ItemTemplate property which I can use within a Viewport3D. My aim is to be able to write something like:
<ItemsControl3D ItemsSource="{Binding Path=MyItems}">
<ItemsControl3D.ItemTemplate>
<DataTemplate3D>
<!-- My template which defines the binding to each item. -->
<DataTemplate3D>
</ItemsControl3D.ItemTemplate>
</ItemsControl3D>
I'm looking for tips on how to implement this. The first tricky part is to create a DataTemplate3D which can construct the Visual3D needed to add to the ItemsControl3D.
I've been using .NET reflector to browse through the implementation of ItemsControl and DataTemplate, but I soon realised that I don't have a deep enough understanding and enough time to come up with a solution on my own.
There's an implementation of ItemsControl3D made by DKT # Pelebyte blog. I haven't tryed it. But I sure will.
Regards