How can I use the properties of the controls that are inside a user control without having to use DependencyProperty?
Since, if for example I want to use all the properties of a button, I would have to declare all these?
And if there is another way without user control and it is the correct one, I would appreciate it if you answered it. (Google translator, sorry)
UserControl:
<UserControl x:Class="UserControls.UserControl01"
...
>
<Grid>
<Button x:Name="uc_btn" />
<TextBox x:Name="uc_txt" />
<DataGrid x:Name="uc_dtg" />
</Grid>
</UserControl>
Code using the UserControl:
<Window x:Class="UserControls.wnd02"
...
>
<Grid>
<local:UserControl01 uc_btn.Background="Red" uc_txt.Margin="10" uc_dtg.BorderThickness="5" Margin="90" />
<local:UserControl01 uc_btn.Background="Green" uc_txt.Margin="25" uc_dtg.BorderThickness="20" Margin="5" />
</Grid>
</Window>
It is not usual to do what you are asking.
Let's consider a usercontrol which is intended to work as if it is one single control. For example a time picker. This contains two sliders which increase/decrease hour and minute. You can also overtype in the hour and minute textboxes and there's a : between the two textboxes.
This usercontrol is all about the one property though. Time. You don't care what the minutes background is externally. If this changes it's internal to the usercontrol.
In this scenario you'd usually add a TimeSpan dependency property to the usercontrol and this is the only thing anything external to it uses.
Pretty much all commercial WPF development uses the MVVM pattern and that TimeSpan would be bound to a property in the parent view's viewmodel.
That's one scenario.
Another is where a usercontrol encapsulates a bunch of UI which is then re-usable.
Styling has scope so when you apply a style to say a Button in a window then that would apply to any Buttons in a usercontrol within it. Setting their properties.
There are also certain dependency properties marked as "inherits" whose values propogate down the visual tree.
One such is DataContext and it is this which most teams would use to deal with properties within a usercontrol.
Using MVVM there would be a MainWindowViewModel.
That would have (say ) a ChildUserControlViewModel property. That would be associated with usercontrol using a datatemplate specified datatype.
You'd then bind properties of whatever is in a usercontrol to properties of ChildUserControlViewModel or properties of MainWindowViewModel using RelativeSource binding.
ViewModel first is a common navigation and composition pattern for WPF. You should be able to find numerous blogs explain it better than I can in a SO post.
Here's one:
https://social.technet.microsoft.com/wiki/contents/articles/30898.simple-navigation-technique-in-wpf-using-mvvm.aspx
I have an MVVM application in which the MainWindow contains a grid with several views.
In one of the viewmodels there is a command which I can activate by using hot keys in its corresponding view. I can only activate the command when I am placed in the part of the MainWindow that contains the specific view.
The following code works fine, if I only want to be able to activate the command in the specific view:
ComponentView.xaml:
...
<UserControl.InputBindings>
<KeyBinding Gesture="CTRL+U" Command="{Binding Path=UploadCmd}"/>
</UserControl.InputBindings>
</UserControl>
I would like to be able to activate the command by using the hot keys from any part of the MainWindow.
This is my failed attempt to do the keybinding in the MainWindow, so that the command can be activated from anywhere:
MainWindow.xaml:
<Window x:Class="MyProgram.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:view="clr-namespace:MyProgram.View"
xmlns:vm="clr-namespace:MyProgram.ViewModel"
...>
<Grid>
// Grid content
</Grid>
<Window.DataContext>
<vm:ComponentViewModel>
<KeyBinding Gesture="CTRL+U" Command="{Binding Path=UploadCmd}"/>
</vm:ComponentViewModel>
</Window.DataContext>
</Window>
Is it possible to somehow let the application know where the command is directly in the xaml?
Three options I can think of:
You could place your commands in your main window and then use relative source binding from the child views to the command in your main window.
{Binding Path=PathToProperty, RelativeSource={RelativeSource AncestorType={x:Type Window}}}
If you are using an mvvm framework, there is often a way to message / communicate between viewmodels. This is usually not the best solution but can be used in the right circumstance.
Use IOC / Dependecy Injection to create a service that is instantiated as a singleton in your viewmodellocator. Then inject this service implementation into the parent and child viewmodels constructors. Then you can call functions/properties from that service from the parent viewmodel that can be accessed by the child viewmodels. I use this for navigation purposes.
What are you trying to do with those commands?
Hope this helps
I'm using MVVM in my project and here is my question. I have a View and corresponding view-model with service reference. This view contains UserControl, which have another UserControl and it also contains nested UserControl. Last UserControl have a method which creates a popup. And in this popup i need service reference from view model. Each user control has own DataContext.
Code explanation.
View xaml:
<UserControl DataContext="{Binding ViewModel}">
<FunctionsList/>
</UserControl>
FunctionsList xaml:
<UserControl>
<Function1/>
<Function2/>
<Function3/>
<Function4/>
</UserControl>
Function3 xaml:
<UserControl/>
Function3 code behind contains CreatePopup method, which creates dialog with a UserControl Function3Popup as Content. And Function3Popup should have Service reference.
What is the best practice here? I have awful solution to pass reference using binding but it seems discouraging to me.
Well, after all I've implemented popup with own ViewModel and resolved it from parent control using command binding in the nested child control. I think it's the best solution here.
I'm creating a wpf user control which is in mvvm pattern.
So we have : view(with no code in codebehind file), viewmodel,model,dataaccess files.
I have MainWindow.xaml as a view file, which I need to bind with MainWindowModel.cs.
Usually, in a a wpf application we can do this with onStartUp event in App.xaml file. But in user control, as we do not have App.xaml...How do I achieve it ?
Please help :(...Thanks in Advance !!!
You can use a ContentControl, with a DataTemplate to bind the UserControl (View) to the ViewModel :
<DataTemplate DataType="{x:Type vm:MyViewModel}">
<v:MyUserControl />
</DataTemplate>
...
<ContentControl Content="{Binding Current}" />
WPF will pick the DataTemplate automatically based on the type of the Content
I know this is an old, answered question, but I have a different approach. I like to make implicit relationships in the App.xaml file:
<Application.Resources>
<DataTemplate DataType="{x:Type ViewModels:KioskViewModel}">
<Views:KioskView />
</DataTemplate>
</Application.Resources>
With this, there is no need to set a DataContext anywhere.
UPDATE >>>
In response to #Vignesh Natraj's request, here is a fuller explanation:
Once you have set up the DataTemplate in a Resources element, you can display the KioskView in this example by adding an instance of the KioskViewModel anywhere in your XAML. This could be filling the MainWindow, or just inside a particular section of the screen. You could also host multiple instances of the KioskViewModel in a ListBox and it will generate multiple KioskView instances.
You can add an instance of the KioskViewModel to your XAML in a couple of ways, depending on your requirements. One way is to declare the XML namespace for the project that contains the KioskViewModel.cs file and simply add an instance of it in a ContentControl to the page where you want your view to appear. For example, if you had a UserControl called MainView and the KioskViewModel.cs file was in a Kiosk.ViewModels namespace, you could use basic XAML like this:
<UserControl x:Class="Kiosk.Views.MainView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ViewModels="clr-namespace:Kiosk.ViewModels">
<UserControl.Resources>
<ViewModels:KioskViewModel x:Key="KioskViewModel" />
<DataTemplate DataType="{x:Type ViewModels:KioskViewModel}">
<Views:KioskView />
</DataTemplate>
</UserControl.Resources>
<ContentControl Content="{StaticResource KioskViewModel}" />
</UserControl>
I prefer to use the MVVM design pattern with WPF, so I would have a base view model class providing useful functionality such as implementing the essential INotifyPropertyChanged interface. I then have a property called ViewModel in the main (top level) view model of type BaseViewModel. This provides me with a nice way to change the ViewModel property to any view model that has derived from BaseViewModel and therefore to be able to change the associated view from the view model.
For example, in the MainViewModel.cs class that is bound to MainView there is a field and relating property:
private BaseViewModel viewModel = new KioskViewModel();
public BaseViewModel ViewModel
{
get { return viewModel; }
set { viewModel = value; NotifyPropertyChanged("ViewModel"); }
}
As you can see, it starts off as a KioskViewModel instance, but can be changed to any other view at any time in response to user interaction. For this setup, the XAML is very similar, but instead of declaring an instance of the view model in the Resources element, we bind to the property in the MainViewModel:
<UserControl x:Class="Kiosk.Views.MainView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ViewModels="clr-namespace:Kiosk.ViewModels">
<ContentControl Content="{Binding ViewModel}" />
</UserControl>
Note that for this example, we would need to declare two (or more to make this approach useful) DataTemplates in the App.xaml file:
<Application.Resources>
<DataTemplate DataType="{x:Type ViewModels:MainViewModel}">
<Views:MainView />
</DataTemplate>
<DataTemplate DataType="{x:Type ViewModels:KioskViewModel}">
<Views:KioskView />
</DataTemplate>
</Application.Resources>
I've been using MVVM Light Toolkit which has a ViewModelLocator class that you can put properties to the viewmodels in. You then create a reference to the ViewModelLocator in your Mainwindow.xaml like so:
<vm:ViewModelLocator x:Key="Locator" d:IsDataSource="True"/>
In the grid panel, or whatever you're using, you can then set the datacontext like this:
<Grid DataContext="{Binding MainWindowViewModel, Source={StaticResource Locator}}">
...
</Grid>
You could also go with MEFedMVVM which potentially adds a bit more flexibility in terms of being able to swap different viewModel implementations into the view.
The flexibility in both of these libraries is that you don't have to use their ViewModel base classes if you don't want to - the ViewModelLocator and the MEFedMVVM can work with any class.
There are endless ways to do it, wich all fall in one of the two categories:"view first" or "model first".
In a "view first" mode the view (e.g. your mainwindow) is created first and then (e.g. in the codebehind) the View instantiates the ViewModel and sets it as its datacontext):
private void WindowLoaded(object sender, EventArgs args)
{
this.DataContext = ViewModelService.GetViewModelX();
}
In a "model first" mode the ViewModel is there first and then instanciated the View.
// method of the viewmodel
public void LoadView()
{
// in this example the view abstracted using an interface
this.View = ViewService.GetViewX();
this.View.SetDataContext(this);
this.View.Show();
}
The examples given here are just one way of many. You could look at the various MVVM frameworks and see how they do it.
We can use ObjectDataProvider to call a method inside an object ..as follows :
<ObjectDataProvider ObjectType="{x:Type local:TemperatureScale}"
MethodName="ConvertTemp"
x:Key="convertTemp">
Is there anyway to do the same using DataTemplate
You can probably look at MSDN. I find it as a good resource, though it doesn't explain how to use usercontrols,you will find your way out.
Hello I have a problem with binding commands to button inside datagrid.
Here should be explanation but it doesn't explain everything.
http://msdn.microsoft.com/en-us/library/dd458928.aspx
What should be in classes in namespace Infrastructure?
Can somebody show me a really basic sample of using this?
not just parts of the code...
The Prism Commanding QuickStart - included with the Prism drop should provide the simple code example you are looking for.
All data-bindings go against the current DataContext unless specified otherwise. The DataContext is inherited down the tree of controls unless a control specifically picks a DataContext.
For example your Button might look like this and would look for the SaveCommand on whatever the DataContext has:
<Button Command="{Binding SaveCommand} />
Your button could also look like this if you wanted to bind to a command exposed on your classes code-behind:
<UserControl x:Name="UserControl">
...
<Button Command="{Binding SaveCommand, ElementName=UserControl}"
...
</UserControl>
Using DelegateCommand is just a way of implementing the ICommand you bind to and that should be visibile in the Prism QuickStart.