I am building a simple application that mainly consists of a TabControl and a StatusBar with an Slider. Each tab hosts an custom control that can be zoomed in & out. The slider in the status bar should give the user the abillity to zoom in & out the content of the currently selected tab. My problem is that I'am unable to assign the sliders value to the currently selected custom control.
Here's the xaml of my TabControl:
<TabControl x:Name="MyTabControl" ItemsSource="{Binding MyItems}">
<TabControl.ContentTemplate>
<DataTemplate>
<controls:MyControl x:Name="foo" DataContext="{Binding}">
</controls:MyControl>
</DataTemplate>
</TabControl.ContentTemplate>
</TabControl>
For the slider I want something like this, but it should be bound to the "foo.bar" property of the currently selected tab:
<Slider
Value="{Binding ElementName=foo, Path=bar}">
</Slider>
Is that possible or is there a better way to use a Slider to adjust and display a property of the currently selected custom control?
You can try adding a Value property to the class (or classes) that are set as the DataContext for each TabItem. Then you could data bind the Slider.Value property to the Value property in the data item from the selected TabItem using the TabControl.SelectedItem property. Try this:
<Slider Value="{Binding Path=SelectedItem.Value, ElementName=MyTabControl}" />
Related
I have a TabControl with a binding for the ItemsSource property. It's bound to a ObservableCollection. When I add an item to the collection, the tabs get created correctly, but only the first tab gets its Grid_Loaded event fired. I'm guessing this is because it's focused. I need to initialize stuff when a new tab opens, it contains a control that needs to be referenced.
<TabControl x:Name="tabSessions"
ItemsSource="{Binding Sessions}"
SelectedIndex="0"
BorderThickness="0"
Padding="0,0,0,0">
<TabControl.ItemTemplate>
<DataTemplate DataType="{x:Type vm:MyViewModel}">
<TextBlock Margin="4,4,16,4" Text="{Binding Name}"></TextBlock>
</DataTemplate>
</TabControl.ItemTemplate>
<TabControl.ContentTemplate>
<DataTemplate>
<Grid Loaded="Grid_Loaded">
<!-- View here -->
</Grid>
</DataTemplate>
</TabControl.ContentTemplate>
</TabControl>
Is there an event that I could use to initialize this? I also need the DataContext to be set, and the view to be initialized.c#
The DataTemplate is reused by the tabs, which is why you're probably only seeing one Loaded event. It's only loaded the first time and then reused when you switch tabs. Only the binded content is changed.
Instead of listening to Loaded on the Grid, you could rather listen to DataContextChanged which will tell you every time the DataContext is set to a new object.
The DataContext will change when you switch tabs. The current tab will be set as the DataContext of the DataTemplate (and by extensions the Grid).
When using a DataTemplate you assume that the view is going to be the same, but the content is going to differ. If this is not the case and the views will differ based on the content, you'll probably want to look into using a DataTemplateSelector. This will let you define several DataTemplates and select one of them to use based on the current DataContext. You can read up on DataTemplateSelector in the Microsoft Docs
I have a very simple XAML
Visibility="Collapsed" X1="1" Margin="-35 0 0 0" Y1="0.4">
<Label.Content>
<Slider Grid.Column="0"
Width="20"
Height="65"
IsDirectionReversed="True"
Maximum="0.1"
Minimum="-4"
Orientation="Vertical"
x:Name="Slider1"
Value="{Binding Source={x:Reference scaleFactorModifier},
Path=ZoomScaleFactor, Mode=TwoWay}" />
</Label.Content>
</Label>
</SciChart:CustomAnnotation.Content>
</SciChart:CustomAnnotation>
Now for some reason I need to set the CustomControl.Content property from code behind. Is there any possibility I move all the label control to some style and template and set the CustomControl content property at runtime with that particular style or template.
Update
Reason for using Code behind
Actually I have Annotations property in my control which could have any control in it as we required. Previously I had used hard coded annotations in my control and placed the controls manually. Now I want to bind the Annotations property. I could create a property of this type and add CustomAnnotation objects in it. But customAnnotation objects need to have labels and other controls in them, how could I do that?
If I have understood your problem correctly, I believe that you can do what you want by using a DataTemplate and a ContentControl. First, define a DataTemplate with your Label in:
<DataTemplate DataType="{x:Type YourPrefix:YourDataType}">
<!-- define your Label here -->
</DataTemplate>
Then you can set the Content property of your CustomControl to a ContentControl that has its own Content property set to an instance of an object of type YourDataType:
<ContentControl Content="{Binding InstanceOfYourDataType}" />
I'm aware that you want to do this programmatically, but that's easy enough to work out:
ContentControl contentControl = new ContentControl();
contentControl.Content = instanceOfYourDataType;
yourCustomControl.Content = contentControl;
I'm wondering if you even really need to use your CustomControl at all, but I'll leave that up to you.
I create a user control from that xaml and then set the CustomControl.Content as new instance of user control. This might not be the best solution, but this is all that I have for now.
Background:
I have a ListBox containing items defined by DataTemplates. Right now, if an object in the list has the property IsEditable set to true, the item's property information will be displayed inside of textboxes (via DataTemplate change), instead of textblocks (so the user can edit the content of that list item)
IsEditable is toggled on/off by a button inside of each list item. I have been told that we need to keep the state of all objects consistent, which means I can't just rebind the ItemsSource and lose everything.
Currently, I'm using this to re-render:
this.lbPoints.Dispatcher.Invoke(DispatcherPriority.Render, new Action(() => { }));
Question:
The aforementioned code snippet KIND OF does its job. By "kind of", I mean, it does eventually cause my data to become re-rendered, but only when I scroll to the bottom of the list and then scroll back up to the item i'm trying to re-render.
1) How can I re-render the data immediately without having to scroll around to get it to show up?
The guys commenting are right that you're going about this the wrong way... there is rarely a need to force a ListBox to re-render. You're probably causing yourself some additional grief trying to switch the DataTemplates (although it is possible). Instead of that, think about data binding the TextBox.IsReadOnly property to your IsEditable property:
<TextBox IsReadOnly="{Binding IsEditable}" Text="{Binding Text}" />
Another alternative is to use a BooleanToVisibilityConverter to show a different Grid in your DataTemplate when your IsEditable property is true. Unfortunately, that Converter doesn't have an inverse operation, so you could create an IsNotEditing property to bind to the Grid in the DataTemplate that is originally displayed. I'm not sure if that's clear... see this example:
<DataTemplate DataType="{x:Type YourPrefix:YourDataType}">
<Grid>
<Grid Visibility="{Binding IsNotEditing, Converter={StaticResource
BooleanToVisibilityConverter}}">
<!-- Define your uneditable UI here -->
</Grid>
<Grid Visibility="{Binding IsEditing, Converter={StaticResource
BooleanToVisibilityConverter}}">
<!-- Define your editable UI here -->
</Grid>
</Grid>
</DataTemplate>
You could also define your own BooleanToVisibilityConverter class that has an IsInverted property, so that you can just use the one IsEditing property. You'd need to declare two Converters still, like this:
<Converters:BoolToVisibilityConverter x:Key="BoolToVisibilityConverter" />
<Converters:BoolToVisibilityConverter x:Key="InvertedBoolToVisibilityConverter"
IsInverted="True" />
Then your XAML would be like this:
<Grid Visibility="{Binding IsEditing, Converter={StaticResource
InvertedBoolToVisibilityConverter}}">
<!-- Define your uneditable UI here -->
</Grid>
<Grid Visibility="{Binding IsEditing, Converter={StaticResource
BoolToVisibilityConverter}}">
<!-- Define your editable UI here -->
</Grid>
I have a LongListSelector and use binding.
When the user selects an Item in LongListSelector, I handle the SelectionChanged event of it and access it this way:
var selectedItem = MyListSelector.SelectedItem as NumbersViewModel;
But I want to change background color of that StackPanel which this selected item is inside it and add a TextBlock beside it:
<phone:LongListSelector.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
.
.
.
</StackPanel>
</DataTemplate>
</phone:LongListSelector.ItemTemplate>
How can I do this type of works on LongListSelector?
(It's a WP8 app)
You can bind the background of the stackpanel to a brush which can be added as a property in your NumbersViewModel. Also you can add the textblock inside the template and bind it's visibility to a boolean property inside your NumbersViewModel.
You can set the value of those properties in your selectionchanged event
I'm starting a new project in WPF and am now looking into using Prism. For now I'm simply trying to set up the navigation of the application using Prism. Unfortunately, my lack of experience with the framework makes it a bit difficult to get started.
To be more precise about my first challenge I have an application with a "navigation/menu" region and a "main" region.
In "navigation/menu" region, I have several checkboxes, in this case we have four of them, which represents a sequential navigation. I.E. we've selected View 2 and View 4.
So, when the user click Start, in "main" region must appear each view selected in that order. Check the below image, View 2 is first. Then when the user press next, must show View 4.
I mean on a more structural level..
if I could only get through the first steps..
Prism support TabControl Region Adapter, navigation can be done using standard requestNavigation method.
You need add all your tab content using Region.Add method to the region in your module's init phase.
view:
<TabControl prism:RegionManger.RegionName="tabRegion" />
C# code:
IRegionManager manager;
manager.Regions["tabRegion"].Views.Add(Container.Resolve(typeof(YourViewType)));
In your viewModel, you should write you navigation command:
public void NextView() {
regionManager.RequestNavigation("tabRegion", new Uri("YourViewType", UriKind.Relative));
}
bind to your "next" button:
<Button Command="{Binding NextViewCommand}" />
If you want to control whether user can navigate to next page, you can implement INavigationAware interface.
If you don't want lost data between navigation, you can make your view model has ContainerMangedLifeCycle or implement IsNavigationTarget method to return true.
Sorry for untested code sample, but you should get the point.
Create a class named ViewVM with a property IsSelected. Must implement INotifyPropertyChanged.
Add an ObservableCollection<View> named Views to your datacontext. Populate it with new instances of ViewVM.
Put an ItemsControl in your Window, with ItemsSource set to Views. The DataTemplate for the ItemsControl items should contain a CheckBox (with IsChecked bound to IsSelected) and a Label.
Add a TabControl to your Window, with ItemSource set to Views. Add a Style for TabItem such that TabItems are only visible if IsSelected is true.
Following the above steps will give you a window containing a list of views with checkboxes, as you requested, and a TabControl displaying only the selected views. Below is the XAML (I have tested this):
<StackPanel>
<ItemsControl ItemsSource="{Binding Path=Views}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox IsChecked="{Binding Path=IsSelected}"></CheckBox>
<TextBlock Text="{Binding Path=Title}"></TextBlock>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
<TabControl ItemsSource="{Binding Path=Views}">
<TabControl.ItemTemplate>
<DataTemplate>
<Grid>
<TextBlock Text="{Binding Path=Title}"></TextBlock>
</Grid>
</DataTemplate>
</TabControl.ItemTemplate>
<TabControl.Resources>
<Style TargetType="TabItem">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=IsSelected}" Value="False">
<Setter Property="Visibility" Value="Collapsed"></Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</TabControl.Resources>
</TabControl>
</StackPanel>
This addresses the structural/design aspect and should give you a good start to creating your solution - you'll also need to create a custom control to use instead of the TabControl. Instead of having tabs, your custom control should contain Next and Previous buttons to navigate between views.