I have MainWindow.xaml page with it's MainViewModel
and would like to add 2 SidePanels using one UserControl, but it should have different ViewModels.
MainViewModel alredy has 2 properties with created SidePanelViewModels:
public MainViewModel()
{
LeftSidePanel = new SidePanelViewModel(PanelSides.Left);
RightSidePanel = new SidePanelViewModel(PanelSides.Right);
}
How to set objects in this properties as DataContext for each UserControl in xaml?
Something like this doesnot work:
<Window DataContext="{Binding MainViewModel, Source={StaticResource Locator}}">
...
<Grid Visibility="{Binding RightSidePanel.PanelVisibility}" Grid.Column="4" Grid.Row="2" >
<v:SidePanelViev DataContext="{Binding RightSidePanel}" />
</Grid>
</Window>
I broke all the brains thinking how to do it, Please help
ps.
Or please suggest any other approach to reach the same target..
I have solved my problem by adding both instances of SidePanelViewModel as Content of ContentControl
<Window DataContext="{Binding MainViewModel, Source={StaticResource Locator}}">
...
<Grid Visibility="{Binding RightSidePanel.PanelVisibility}" Grid.Column="4" Grid.Row="2" >
<ContentControl Content="{Binding RightSidePanel}"></ContentControl>
</Grid>
</Window>
and adding new Window.Resource what binds all classes of type SidePanelViewModel to be visualised using SidePanelViev
<Window.Resources>
<DataTemplate DataType="{x:Type vm:SidePanelViewModel}">
<v:SidePanelViev></v:SidePanelViev>
</DataTemplate>
</Window.Resources>
This works, but if somebody has better ideas, please do not hesitate to post them, I am not sure that my decision is good one
Related
I've added a content presenter to my TabControl's data template, in order to display the correct view.
But when I load the application, the tabs display but they have no user control content.
I Googled the error and came across this solution, that suggested an error with the data context but the setup seems ok in my AppVM and AppView below.
The names of both VM's and Views are also correct that I'm referencing in the AppView.
Does anyone have an idea where the setup has gone wrong here?
This is the ApplicationView that holds both views:
<Window x:Class="MongoDBApp.Views.ApplicationView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:views="clr-namespace:MongoDBApp.Views"
xmlns:vm="clr-namespace:MongoDBApp.ViewModels"
Title="ApplicationView"
Width="800"
Height="500">
<Window.Resources>
<DataTemplate DataType="{x:Type vm:CustomerDetailsViewModel}">
<views:CustomerDetailsView />
</DataTemplate>
<DataTemplate DataType="{x:Type vm:CustomerOrdersViewModel}">
<views:CustomerOrdersView />
</DataTemplate>
</Window.Resources>
<Window.DataContext>
<vm:ApplicationViewModel />
</Window.DataContext>
<TabControl ItemsSource="{Binding PageViewModels}" TabStripPlacement="Top">
<TabControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}" />
</DataTemplate>
</TabControl.ItemTemplate>
<TabControl.ContentTemplate>
<DataTemplate>
<ContentPresenter Content="{Binding CurrentPageViewModel}" />
</DataTemplate>
</TabControl.ContentTemplate>
</TabControl>
</Window>
ApplicationViewModel constructor and related fields:
private ICommand _changePageCommand;
private IPageViewModel _currentPageViewModel;
private List<IPageViewModel> _pageViewModels;
private static ICustomerDataService customerDataService = new CustomerDataService(CustomerRepository.Instance);
#endregion
/// <summary>
/// Initializes a new instance of the <see cref="ApplicationViewModel"/> class.
/// </summary>
public ApplicationViewModel()
{
// Add available pages
PageViewModels.Add(new CustomerDetailsViewModel(customerDataService));
PageViewModels.Add(new CustomerOrdersViewModel());
// Set starting page
CurrentPageViewModel = PageViewModels[0];
}
The ContentTemplate property wraps the Content object.
For example, with your code you are setting the .Content property to a CustomerDetailsViewModel object, and trying to bind to the CurrentPageViewModel of that object, which doesn't exist.
What is getting rendered is :
<TabControl>
<TabItem>
<ContentPresenter Content=CustomerDetailsViewModel>
<ContentPresenter Content="{Binding CurrentPageViewModel}" />
</ContentPresenter>
</TabItem>
<TabItem>
<ContentPresenter Content=CustomerOrdersViewModel>
<ContentPresenter Content="{Binding CurrentPageViewModel}" />
</ContentPresenter>
</TabItem>
</TabControl>
Because the TabControl will auto-generate a ContentPresenter to wrap the .Content for each TabItem, you don't need this template at all.
But what it sounds like what you actually want is to bind the SelectedItem property of the TabControl
<TabControl ItemsSource="{Binding PageViewModels}"
SelectedItem="{Binding CurrentPageViewModel}"
TabStripPlacement="Top">
<TabControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}" />
</DataTemplate>
</TabControl.ItemTemplate>
</TabControl>
We don't generally use a ContentPresenter outside of a ControlTemplate and certainly not like you are doing in your DataTemplate... the use of the ContentPresenter will make the WPF Framework search for a DataTemplate that matches the type of the Content, so in your case, you'll end up with an endless loop. Instead, you should put your associated view in the DataTemplate:
<DataTemplate DataType="{x:Type YourDataXamlPrefix:CurrentPageViewModel}">
<YourUiXamlPrefix:YourView DataContext="{Binding CurrentPageViewModel}" />
</DataTemplate>
In this way, when the Framework comes across your view model class in the collection, it will find this DataTemplate and render the relevant view.
EDIT:
Here is a small sample Solution (VS 2013) showing my exact problem: nakkvarr.net/TestApp.zip
I have two views:
MainView
EmployeeView
I want my EmployeeView to reference the MainViewModel property "employees".
I tried this:
<DockPanel DataContext="{Binding DataContext.MainViewModel,
RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type EmployeeLisViewModel}}}">
But all I get is the Error: EmployeeListViewModel ist not supported in WPF ?!
(EmployeeListViewModel is also the name of the property of my MainViewModel)
The thing is:
My MainView has some menu items. One is for sorting the employee list, which is inside my UserControl. My UserControl ViewModel contains the Commands for sorting.
EDIT:
I changed it to vm:EmployeeListViewModel ... now the error is gone...but now I don't seem to get access to the ViewModel :/
<ia:InvokeCommandAction Command="{Binding LoadEmployeesCommand}"
Does not trigger, no emplyees get loaded. When I use the ViewModel directly, it works just fine.
MainWindow.xaml
<Window x:Class="de.XXX.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:controls="clr-namespace:de.XXX.Views"
xmlns:vm="clr-namespace:de.XXX.ViewModel"
Icon="/Images/App.ico"
Style="{StaticResource MainWindowStyle}"
Title="MainWindow">
<DockPanel DataContext="{Binding MainViewModel, Source={StaticResource Locator}}">
<Menu DockPanel.Dock="Top">
...
</Menu>
<controls:EmployeeListView DockPanel.Dock="Bottom" DataContext="{Binding EmployeeListViewModel}" />
</DockPanel>
</Window>
EmployeeListView.xaml //not model, copy & paste error x_X
<UserControl x:Class="de.XXX.Views.EmployeeListView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:vm="clr-namespace:de.XXX.ViewModel"
xmlns:ia="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
mc:Ignorable="d"
d:DesignHeight="350" d:DesignWidth="350">
<DockPanel DataContext="{Binding MainViewModel,
RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type vm:EmployeeListViewModel}}}">
<ListBox DockPanel.Dock="Bottom" x:Name="EmployeeList" ItemsSource="{Binding EmployeeList}" ScrollViewer.CanContentScroll="False" />
<ia:Interaction.Triggers>
<ia:EventTrigger EventName="Loaded">
<ia:InvokeCommandAction Command="{Binding LoadEmployeesCommand}" />
</ia:EventTrigger>
</ia:Interaction.Triggers>
</DockPanel>
</UserControl>
If you modify your SubControl to below, this should work.
<Grid DataContext="{Binding Path=DataContext.SubVM, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Window}}}">
I have a hint on what you are trying to achieve and I guess you have missed some details on Binding especially on other underlying properties needed to be set. This part is working based on the given code. But then, there are numerous ways in making it better. Good luck.
I think there might be a combination of misunderstandings here! Your UserControl has
x:Class="de.XXX.Views.EmployeeListView"
defined as the class name in xaml. However, you're also saying that the file is named EmployeeListViewModel.xaml? A .xaml file should never be named a viewmodel. I believe you should have MainWindow.xaml, EmployeeListView.xaml, MainWindowViewModel.cs, and EmployeeListViewModel.cs, is this the case?
Also, in your MainWindow.xaml, you're already setting the datacontext of your EmployeeListView usercontrol:
<controls:EmployeeListView DockPanel.Dock="Bottom" DataContext="{Binding EmployeeListViewModel}" />
This implies to me that your class structure is that MainViewModel contains an instance of the EmployeeListViewModel... is this true?
If all the above is true, then this part of your UserControl xaml does not make sense:
<DockPanel DataContext="{Binding MainViewModel,
RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type vm:EmployeeListViewModel}}}">
Whether EmployeeListViewModel is actually your view and not your viewmodel, the property "MainViewModel" does not exist on EmployeeListViewModel, so the binding will never work.
If you're trying to have a reference to your Window's DataContext, MainViewModel, within your UserControl, a possible way to do this is:
MainWindow.xaml:
<controls:EmployeeListView DockPanel.Dock="Bottom" DataContext="{Binding}" />
This should set the DataContext of your EmployeeListView to MainViewModel. Then, in your EmployeeListView, you can do this:
<UserControl x:Class="de.XXX.Views.EmployeeListView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:vm="clr-namespace:de.XXX.ViewModel"
xmlns:ia="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
mc:Ignorable="d"
d:DesignHeight="350" d:DesignWidth="350">
<DockPanel
<ListBox DockPanel.Dock="Bottom" x:Name="EmployeeList" ItemsSource="{Binding EmployeeList}" ScrollViewer.CanContentScroll="False" />
<ia:Interaction.Triggers>
<ia:EventTrigger EventName="Loaded">
<ia:InvokeCommandAction Command="{Binding EmployeeListViewModel.LoadEmployeesCommand}" />
</ia:EventTrigger>
</ia:Interaction.Triggers>
</DockPanel>
</UserControl>
There's a lot of assumptions about your views and viewmodels I made for this answer. I hope this at least helps. If it doesn't make any sense, please post your viewmodels as well :)
I have the following MainWindow that lays out a left side navigation panel and a right side display area (both of these are UserControls).
Can someone explain how to assign the DataContext of the navigation panel (LinksView.xaml) to that of LinksViewModel.cs. I would like to bind a Command (BtnCompanyClickCommand) to the button and define BtnCompanyClickCommand in LinksViewModel.cs.
I have tried various methods that I found on StackOVerflow to set the DataContext but none of these solutions seem to work (binding RelativeSource, naming view and binding to name, etc.).
MainWindow.xaml
<StackPanel Orientation="Horizontal">
<vw:LinksView DataContext="{Binding RelativeSource={RelativeSource Self}}"/>
<ContentControl Content="{Binding CurrentUserControl}" />
</StackPanel>
LinksView.xaml
<StackPanel Orientation="Vertical">
<Button Content="Company" Width="75" Margin="3" Command="{Binding ElementName=Links,Path=BtnCompanyClickCommand}" />
</StackPanel>
FormsDictionary.xaml
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="clr-namespace:SidekickAdmin.ViewModel"
xmlns:vw="clr-namespace:SidekickAdmin.View">
<DataTemplate DataType="{x:Type vm:CompanySummaryViewModel}">
<vw:CompanySummaryView>
<ContentControl Content="{Binding }" />
</vw:CompanySummaryView>
</DataTemplate>
<DataTemplate DataType="{x:Type vm:LinksViewModel}">
<vw:LinksView />
</DataTemplate>
</ResourceDictionary>
EDIT
So I finally came across this explanation of how to set the DataContext of a UserControl which has to be done on the first child item of the UserControl.
Here is the modified LinksView.xaml that works.
<StackPanel Orientation="Vertical">
<StackPanel.DataContext>
<vm:LinksViewModel /> <!-- Bind the items in StackPanel to LinksViewModel -->
</StackPanel.DataContext>
<Button Content="Company" Width="75" Margin="3" Command="{Binding BtnCompanyClickCommand}" />
</StackPanel>
However, I am still not clear on why I have to set the DataContext of the child element and not the UserControl and why the DataTemplate for LinksView (set in FormsDictionary.xaml) doesn't tie into the DataContext of LinksViewModel. Any explanation would be appreciated.
First you have to refer to your DataContext (LinksViewModel.cs) in your XAML code.
You can do that either by directly instantiating it or use a ResourceDictionary. In the latter case you instantiate your DataConext either inside some .cs file or inside the ResourceDictionary .xaml file and store it in a named ResourceDictionary where you can find the reference later.
Second you simply have to associate the DataContext property of a View element like your LinksView.xaml with the corresponding DataContext.
This is pretty high-level and without any code but that's the basic idea behind it.
there should be an instance of LinksViewModel in MainWindowViewModel:
MainWindowViewModel.cs:
class MainWindowViewModel
{
public MainWindowViewModel()
{
LinksVM = new LinksViewModel();
}
public LinksViewModel LinksVM { get; private set; }
}
MainWindow.xaml
<StackPanel Orientation="Horizontal">
<vw:LinksView DataContext="{Binding LinksVM}"/>
<ContentControl Content="{Binding CurrentUserControl}" />
</StackPanel>
LinksView.xaml
<StackPanel Orientation="Vertical">
<Button Content="Company" Width="75" Margin="3" Command="{Binding BtnCompanyClickCommand}" />
</StackPanel>
since LinksView is explicitly created in MainWindow, there is no need in DataTemplate - it can be removed
<DataTemplate DataType="{x:Type vm:LinksViewModel}">
<vw:LinksView />
</DataTemplate>
I need some quick help which is a road blocker for me now. I have Button in ItemsControl and I need to perform some task on Button click. I tried adding Command to Button in ItemsControl DataTemplate but its not working. Can anyone suggest how to proceed further.
<UserControl.Resources>
<DataTemplate x:key="mytask">
<TextBox Grid.Row="5" Grid.Column="2" Text="{Binding Path=PriorNote}" Grid.ColumnSpan="7" VerticalAlignment="Center" HorizontalAlignment="Left" Margin="0,5" Width="505" Foreground="Black"/>
<StatusBarItem Grid.Row="2" Grid.Column="8" Margin="8,7,7,8" Grid.RowSpan="2">
<Button x:Name="DetailsButton" Command="{Binding CommandDetailsButtonClick}">
</DataTemplate>
</UserControl.Resources>
<Grid>
<ItemsControl Grid.Row="1"
ItemsSource="{Binding ListStpRules}"
ItemTemplate="{StaticResource myTaskTemplate}" Background="Black"
AlternationCount="2" >
</ItemsControl>
</Grid>
and in ViewModel I have implemented code for Command. And its not working. Please suggest any solution for me to proceed further
The DataContext of each item in your ItemsControl is the item in the collection the ItemsControl is bound to. If this item contains the Command, your code should work fine.
However, this is not usually the case. Typically there is a ViewModel containing an ObservableCollection of items for the ItemsControl, and the Command to execute. If this is your case, you'll need to change the Source of your binding so it looks for the command in ItemsControl.DataContext, not ItemsControl.Item[X]
<Button Command="{Binding
RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}},
Path=DataContext.MyCommand}" />
If your ViewModel has a property of type ICommand you can bind the Button's Command property to that:
XAML:
<DataTemplate DataType="{x:Type my:FooViewModel}">
<Button Content="Click!" Command="{Binding Path=DoBarCommand}" />
</DataTemplate>
C#:
public sealed class FooViewModel
{
public ICommand DoBarCommand
{
get;
private set;
}
//...
public FooViewModel()
{
this.DoBarCommand = new DelegateCommand(this.CanDoBar, this.DoBar);
}
}
Read this:
http://msdn.microsoft.com/en-us/magazine/dd419663.aspx
Implement a class similar to RelayCommand in the above article. Would make your further MVVM coding easier. :-)
Just a guess. Is CommandDetailsButtonClick defined in a ViewModel, which is DataContext of your UserControl (the one with ListStpRules property)?
DataContext of button in ItemTemplate is an item from ListStpRules, and if you command is not there then binding won't find it.
You can check diagnostic messages from wpf in Output window while debugging your application. It writes there if it can not resolve binding.
I wrote simple code like
public ObservableCollection<string> Names …
public Window1()
{
PutInDataIntoNames();
InitializeComponent();
this.listBox1.ItemsSource = Names;
}
and in xaml
<Grid>
<ListBox Margin="10,11,10,16"
Name="listBox1"
Background="Black"
Foreground="Orange"
/>
</Grid>
Then I wanted to set ItemsSource property in xaml. In order to do that I wrote the following:
ItemsSource="{Binding Path=Names}"
Unfortunately, it doesn’t work. Could you explain why and how to do that right?
If you only specify the binding path the binding engine will try to navigate the path starting from the current DataContext so ItemsSource="{Binding Path=Names}" does not work like this, there are a lot of different things to keep in mind especially when doing more complex things.
The single most important article that everyone who is new to DataBinding should read is the Data Binding Overview on MSDN
To get back to your binding, if you want to do it completely in XAML you can do that as well, you just need to make the Window your source somehow, either by referencing it directly or relatively or by setting it up as the DataContext.
1 - Direct Reference:
<Window Name="Window"
...>
<Grid>
<ListBox ...
ItemsSource="{Binding ElementName=Window, Path=Names}"
.../>
</Grid>
</Window>
2 - Relative Reference
<Grid>
<ListBox ...
ItemsSource="{Binding RelativeSource={RelativeSource AncestorType=Window}, Path=Names}"
.../>
</Grid>
3 - Setting up the DataContext
<Window ...
DataContext="{Binding RelativeSource={RelativeSource Mode=Self}}">
<Grid>
<ListBox ...
ItemsSource="{Binding Path=Names}"
.../>
</Grid>
</Window>
Do this in code behind
public Window1()
{
PutInDataIntoNames();
InitializeComponent();
DataContext = this;
}
and in XAML
<Grid>
<ListBox ItemsSource="{Binding Names}"
Margin="10,11,10,16"
Name="listBox1"
Background="Black"
Foreground="Orange"
/>
</Grid>
Ideally you should follow MVVM design to isolate data from code behind.
It seems that your Names might be a field. You can ONLY bind to public properties