I have an ItemsControl element that populates a Stackpanel. Its bound to a ObservableCollections full of "LedModel" objects (see below).
I cannot get the binding for Brush, Size and BlurRadius to work.
Oddly enough however the binding for the Label does work...
<ItemsControl
ItemsSource="{Binding ElementName=Control, Path=Leds}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel
Orientation="Vertical"
IsItemsHost="True" />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid>
<Ellipse
Width="{Binding Size}"
Height="{Binding Size}"
Fill="{Binding Brush}">
<Ellipse.Effect>
<BlurEffect
Radius="{Binding BlurRadius}" />
</Ellipse.Effect>
</Ellipse>
<Label Content="{Binding ColorString}" />
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
public partial class LEDStack : UserControl, INotifyPropertyChanged {
// ...
public ObservableCollection<LEDModel> Leds { get; }
// ...
}
public class LEDModel {
public string ColorString => GetColorString();
public SolidColorBrush Brush { get; set; } = Brushes.Orange; //does not bind
public double Size { get; set; } = 25d; // does not bind
public double BlurRadius { get; set; } = 10d; // does not bind
private string GetColorString() {
return $"{Brush.Color.R}, {Brush.Color.G}, {Brush.Color.B}";
}
}
It does not throw me any error or warning in IDE, during compile or at runtime.
My IDE also shows me the binding worked correctly and when inspecting the UI tree I see the stackpanel was properly populated (and I can see all the labels in my app)
Using Brush or Color instead of SolidColorBrush --> did not work
Using int or float for Size / BlurRadius --> did not work
Solution: I needed to implement INotifyPropertyChanged in LedModel.cs to make modification of individual objects in the Collection be reflected in the UI
Related
I am trying to create a Side menu in wpf as shown in the image...
The menu is binded to an ObservableCollection (MenuList) of the class
public class MenuItemModel
{
public int MenuID { get; set; }
public string MenuName { get; set; }
public ObservableCollection<MenuItemModel> SubMenuList { get; set; }
}
The Xaml I have been using for two level,
<ItemsControl ItemsSource="{Binding MenuList}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel>
<RadioButton x:Name="Menu"
Tag="{Binding MenuID}"
GroupName="MainMenu"
Style="{StaticResource MenuButtonStyle}"
Content="{Binding MenuName}"
Height="30"/>
<ListBox x:Name="SubMenu" ItemsSource="{Binding SubMenuList}"/>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
It works perfectly for two levels. But I am unable to figure out how to implement third level menus (like version1, version2 in the image)? Is there any way to do this in the xaml without changing Data Models?
I've got two data templates in the resources and a DataTemplateSelector to choose between them:
<DataGrid.Resources>
<DataTemplate x:Key="RedTemplate">
<TextBlock Text="{Binding **Name1OrName2**}" />
</DataTemplate >
<DataTemplate x:Key="GreenTemplate">
....
</DataTemplate>
<local:MyTemplateSelector x:Key="MyTemplateSelector"
RedTemplate="{StaticResource RedTemplate}"
GreenTemplate="{StaticResource GreenTemplate}" />
</DataGrid.Resources>
Here is the code-behind of the selector:
public class MyTemplateSelector : DataTemplateSelector
{
public DataTemplate RedTemplate { get; set; }
public DataTemplate GreenTemplate { get; set; }
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
if (item is RedItem) return RedTemplate;
else if (item is GreenItem) return GreenTemplate;
else return base.SelectTemplate(item, container);
}
}
As long as I use MyTemplateSelector for one DataColumn (say, Name1), it works fine. But my DataGrid has two template columns to be bound to two string fields: Name1 and Name2
<DataGridTemplateColumn CellTemplateSelector="{StaticResource MyTemplateSelector}" > // Should be bound to Name1
<DataGridTemplateColumn CellTemplateSelector="{StaticResource MyTemplateSelector}" > // Should be bound to Name2
My question is: how can I set the proper Path (Name1 or Name2) in the Binding (instead of Name1OrName2, see above). Thank you.
It looks like my original answer was due to a misunderstanding of the question, and the requirement isn't about the data template selector, but rather how to parameterize the property a binding binds to, so you can use the same template for two different properties.
Quick answer: That's not the way XAML is designed to be used. You can't parameterize the Path property of a Binding. The conventional solution is to write one template for each case. It would be nice if you could specify which property/field a DataGridTemplateColumn is meant to display, via a Binding or DisplayMemberPath property, and then passed that value to the template -- but it doesn't work that way.
I found a likely-looking workaround here, but I'm not sure the ROI on it would stack up well relative to copying and pasting a DataTemplate and getting on with your life.
If the templates are complicated enough for maintenance to be a concern, you can work around that like so:
XAML resources:
<DataTemplate x:Key="RedBaseTemplate">
<Border BorderBrush="Green" BorderThickness="2" Margin="1">
<Label x:Name="Text" Background="Red" Content="{Binding}" />
</Border>
</DataTemplate>
<DataTemplate x:Key="GreenBaseTemplate">
<Border BorderBrush="Red" BorderThickness="2" Margin="1">
<Label x:Name="Text" Background="Green" Content="{Binding}" />
</Border>
</DataTemplate>
<DataTemplate x:Key="RedTemplateA">
<ContentControl
Content="{Binding A}"
ContentTemplate="{StaticResource RedBaseTemplate}"
/>
</DataTemplate>
<DataTemplate x:Key="RedTemplateB">
<ContentControl
Content="{Binding B}"
ContentTemplate="{StaticResource RedBaseTemplate}"
/>
</DataTemplate>
<DataTemplate x:Key="GreenTemplateA">
<ContentControl
Content="{Binding A}"
ContentTemplate="{StaticResource GreenBaseTemplate}"
/>
</DataTemplate>
<DataTemplate x:Key="GreenTemplateB">
<ContentControl
Content="{Binding B}"
ContentTemplate="{StaticResource GreenBaseTemplate}"
/>
</DataTemplate>
Original Answer
This is a common pattern: You want multiple instances of the same DataTemplateSelector (or value converter, quite often), but with different parameters. The solution is to derive from MarkupExtension, so you can instantiate the thing at the point of use with its own unique parameters, rather than creating one shared instance someplace else as a resource. In this case DataTemplateSelector is a class rather than an interface, so you can't derive your selector from MarkupExtension. Instead you write a quick MarkupExtension that returns your selector.
I wanted to pass the templates themselves to RedGreenTemplateSelectorExtension using StaticResource or DynamicResource in the XAML, but the XAML parser didn't like the idea. But this works well enough.
public class RedGreenTemplateSelectorExtension : MarkupExtension
{
public Object RedTemplateKey { get; set; }
public Object GreenTemplateKey { get; set; }
public override object ProvideValue(IServiceProvider serviceProvider)
{
var redTemplate = new StaticResourceExtension(RedTemplateKey)
.ProvideValue(serviceProvider) as DataTemplate;
var greenTemplate = new StaticResourceExtension(GreenTemplateKey)
.ProvideValue(serviceProvider) as DataTemplate;
return new RedGreenTemplateSelector() {
RedTemplate = redTemplate,
GreenTemplate = greenTemplate
};
}
}
public class RedGreenTemplateSelector : DataTemplateSelector
{
public DataTemplate RedTemplate { get; set; }
public DataTemplate GreenTemplate { get; set; }
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
if (item is RedItem)
return RedTemplate;
else if (item is GreenItem)
return GreenTemplate;
else
return base.SelectTemplate(item, container);
}
}
XAML
<StackPanel>
<ContentControl
ContentTemplateSelector="{local:RedGreenTemplateSelector RedTemplateKey=RedTemplate, GreenTemplateKey=GreenTemplate}"
>
<local:RedItem/>
</ContentControl>
<ContentControl
ContentTemplateSelector="{local:RedGreenTemplateSelector RedTemplateKey=RedTemplate, GreenTemplateKey=GreenTemplate}"
>
<local:GreenItem/>
</ContentControl>
</StackPanel>
P.S. StaticResource and Binding are two very different classes that do very different things. People misuse "binding" to mean "assignment". It's not. You aren't using any bindings at all here.
How do I wrap or otherwise display long strings in my listview control. I have been unsuccessful in wrapping, or otherwise displaying long text in my bound ListView control. My xaml page is basically a BOUND FlipView with an ItemTemplate that contains two bound textBlocks and a bound ListView. I can get the TextBlocks to wrap but not the listviewitems. It would seem like such a simple thing yet it eludes me.
Here is a portion of my xaml:
<Page.Resources>
<DataTemplate x:DataType="data:MydataObject" x:Key="MydataObjectTemplate">
<StackPanel HorizontalAlignment="Stretch" Height="596" Width="982">
<TextBlock Name="txtDataObjectId" Text="{Binding dataObject.Id}" Visibility="Collapsed" TextWrapping="WrapWholeWords"/>
<TextBlock FontSize="24" Text="{x:Bind dataObject}" HorizontalAlignment="Center" TextWrapping="WrapWholeWords"/>
<ListView ItemsSource ="{x:Bind theObjectDetails, Mode=OneWay }"
HorizontalAlignment="Stretch"
BorderBrush="Black"
BorderThickness="1"/>
</StackPanel>
</DataTemplate>
</Page.Resources>
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<StackPanel HorizontalAlignment="Stretch">
<ComboBox x:Name="cboCategory" Header="Category" SelectionChanged="cboCategory_SelectionChanged" />
<FlipView x:Name="FlipView1"
ItemsSource="{x:Bind MydataObjects, Mode=OneWay }"
ItemTemplate="{StaticResource MydataObjectTemplate}"
BorderBrush="Black"
BorderThickness="1"/>
</StackPanel>
</Grid>
//c#
public class mydataObject
{
public int Id { get; set; }
public dataObject theObject { get; set; }
public List<dataObjectDetails> theObjectDetails { get; set; }
public override string ToString()
{
return this.theObject.Subject;
}
}
public class dataObjectDetails
{
public int Id { get; set; }
public int dodId{ get; set; }
public string bodyText { get; set; }
public override string ToString()
{
return bodyText ;
}
}
Give the ListView an ItemTemplate, which puts the content in a TextBlock that wraps the text:
<ListView
ItemsSource="{x:Bind theObjectDetails, Mode=OneWay}"
HorizontalAlignment="Stretch"
>
<ListView.ItemTemplate>
<DataTemplate>
<Grid>
<TextBlock
Text="{Binding bodyText}"
TextWrapping="WrapWholeWords"
/>
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
I am trying to display a tooltip for an item generated by an ItemsControl that needs to pull data from conceptually unrelated sources. For example, say I have an Item class as follows:
public class Item
{
public string ItemDescription { get; set; }
public string ItemName { get; set; }
}
I can display the Item within an ItemsControl with a tooltip as follows:
<ItemsControl x:Name="itemsControl" ItemsSource="{Binding Items}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding ItemName}">
<TextBlock.ToolTip>
<ToolTip>
<TextBlock Text="{Binding ItemDescription}" />
</ToolTip>
</TextBlock.ToolTip>
</TextBlock>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
But say I have another property that can be accessed via the DataContext of the ItemsControl. Is there any way to do this from within the tooltip? E.g.,
<ItemsControl x:Name="itemsControl" ItemsSource="{Binding Items}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding ItemName}">
<TextBlock.ToolTip>
<ToolTip>
<Grid>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<TextBlock Text="{Binding ItemDescription}" />
<TextBlock Grid.Row="1" Text="{Bind this to another property of the ItemsControl DataContext}" />
</Grid>
</ToolTip>
</TextBlock.ToolTip>
</TextBlock>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
The code for the test Window I used is as follows:
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
List<Item> itemList = new List<Item>() {
new Item() { ItemName = "First Item", ItemDescription = "This is the first item." },
new Item() { ItemName = "Second Item", ItemDescription = "This is the second item." }
};
this.Items = itemList;
this.GlobalText = "Something else for the tooltip.";
this.DataContext = this;
}
public string GlobalText { get; private set; }
public List<Item> Items { get; private set; }
}
So in this example I want to show the value of the GlobalText property (in reality this would be another custom object).
To complicate matters, I am actually using DataTemplates and show two different types of objects within the ItemsControl, but any assistance would be greatly appreciated!
After an hour of hair pulling I have come to the conviction that you can't reference another DataContext inside a DataTemplate for a ToolTip. For other Bindings it is perfectly possible as other posters have proven. That's why you can't use the RelativeSource trick either. What you can do is implement a static property on your Item class and reference that:
<Window x:Class="ToolTipSpike.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300"
Name="Root"
xmlns:ToolTipSpike="clr-namespace:ToolTipSpike">
<Grid>
<ItemsControl x:Name="itemsControl" ItemsSource="{Binding Items}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding ItemName}">
<TextBlock.ToolTip>
<ToolTip>
<Grid>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<TextBlock Text="{Binding ItemDescription}" />
<TextBlock Grid.Row="1"
Text="{Binding Source={x:Static ToolTipSpike:Item.GlobalText},
Path=.}"
/>
</Grid>
</ToolTip>
</TextBlock.ToolTip>
</TextBlock>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</Grid>
</Window>
using System.Collections.Generic;
using System.Windows;
namespace ToolTipSpike
{
public partial class Window1 : Window
{
public List<Item> Items { get; private set; }
public Window1()
{
InitializeComponent();
var itemList = new List<Item>
{
new Item { ItemName = "First Item", ItemDescription = "This is the first item." },
new Item { ItemName = "Second Item", ItemDescription = "This is the second item." }
};
this.Items = itemList;
this.DataContext = this;
}
}
public class Item
{
static Item()
{
GlobalText = "Additional Text";
}
public static string GlobalText { get; set; }
public string ItemName{ get; set;}
public string ItemDescription{ get; set;}
}
}
Second attempt
Ok, the Relative Source Binding doesn't work in this case. It actually works from a data template, you can find many examples of this on the Internets. But here (you were right, David, in your comment) ToolTip is a special beast that is not placed correctly in the VisualTree (it's a property, not a control per se) and it doesn't have access to the proper name scope to use relative binding.
After some more searching I found this article, which describes this effect in details and proposes an implementation of a BindableToolTip.
It might be an overkill, because you have other options -- like using a static property on a class (as in Dabblernl's response) or adding a new instance property to your Item.
First attempt :)
You should consult with the Relative Source Binding types (in this cheat sheet for example):
So your binding will look somehow similar to this:
{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ItemsControl}}, Path= GlobalText}
Almost correct Yacoder, and guessed way wrong there Dabblernl ;)
Your way of thinking is correct and it is possible to reference the DataContext of your ItemsControl
You are missing the DataContext property in path:
{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ItemsControl}}, Path=DataContext.GlobalText}
Second attempt ;)
http://blogs.msdn.com/tom_mathews/archive/2006/11/06/binding-a-tooltip-in-xaml.aspx
Here is an article with the same problem. They can reference the DataContext of their Parent control by the PlacementTarget property:
<ToolTip DataContext=”{Binding RelativeSource={RelativeSource Self},Path=PlacementTarget.Parent}”>
If you would place the DataContext on a deeper level, you avoid changing your Item DataContext
A second suggestion (Neil and Adam Smith) was that we could use PlacementTarget in the binding. This is nice, as I am actually inheriting the DataContext already from the page that hosts the DataControl, and this would allow the ToolTip to gain access back to the origial control. As Adam noted, though, you have to be aware of the parent/child structure off your markup:
This is a case where I think it's conceptually more appropriate to do this in the view model than it is in the view anyway. Expose the tooltip information to the view as a property of the view model item. That lets the view do what it's good at (presenting properties of the item) and the view model do what it's good at (deciding what information should be presented).
I had a very similar problem and arrived at this question seeking answers. In the end I came up with a different solution that worked in my case and may be useful to others.
In my solution, I added a property to the child item that references the parent model, and populated it when the children were generated. In the XAML for the ToolTip, I then simply referenced the property from the parent model on each element and set the DataContext to the parent model property.
I felt more comfortable with this solution than creating proxy elements in XAML and referencing them.
Using the example code for this question, you would do the following. Note I have not tested this scenario in a compiler, but have done so successfully implemented this solution in the code for my own scenario.
Item:
public class Item
{
public List<Item> Parent { get; set; }
public string ItemDescription { get; set; }
public string ItemName { get; set; }
}
Window:
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
List<Item> itemList = new List<Item>();
itemList.Add(new Item() { Parent = this, ItemName = "First Item", ItemDescription = "This is the first item." });
itemList.Add(new Item() { Parent = this, ItemName = "Second Item", ItemDescription = "This is the second item." });
this.Items = itemList;
this.GlobalText = "Something else for the tooltip.";
this.DataContext = this;
}
public string GlobalText { get; private set; }
public List<Item> Items { get; private set; }
}
XAML:
<ItemsControl x:Name="itemsControl" ItemsSource="{Binding Items}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding ItemName}">
<TextBlock.ToolTip>
<ToolTip>
<Grid>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<TextBlock Text="{Binding ItemDescription}" />
<TextBlock Grid.Row="1" DataContext={Binding Parent} Text="{Bind this to aproperty of the parent data model}" />
</Grid>
</ToolTip>
</TextBlock.ToolTip>
</TextBlock>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
I have one Listbox and applied one DataTemplate like this
<ListBox>
<ListBox.ItemTemplate>
<Grid>
<TextBlock Text="{Binding Path=Name}" Grid.Row=0/>
<ComoboBox Name="test"
DisplayMemberPath="Country"
SelectedValuePath="Country_ID">
</Grid>
How will I load ItemSource to this ComboBox dynamically based on each item selected in the ListBox? Iam new to WPF... pls help with your valuable suggestions.
<ListBox>
<ListBox.ItemTemplate>
<Grid>
<TextBlock Text="{Binding Path=Name}" Grid.Row=0/>
<ComoboBox Name="test"
DataContent="{Binding RelativeSource={RelativeSource AncestorType=ListBox}}"
ItemsSource="{Binding}"
DisplayMemberPath="Country"
SelectedValuePath="Country_ID">
</Grid>
Now your combocbox is always have the same itemssource as the parent listbox.
One way to do this is to bind the ItemsSource of your ComboBox to the SelectedValue property of the ListBox. For this to work the ListBox needs to be bound to a collection of items that contains a list of items that the ComboBox will bind to.
<ListBox
x:Name="CategoryList"
ItemsSource="{Binding Path=MasterList,
RelativeSource={RelativeSource AncestorType=Window}}"
DisplayMemberPath="MasterProperty"
SelectedValuePath="Details"
/>
<ComboBox
ItemsSource="{Binding Path=SelectedValue, ElementName=CategoryList}"
DisplayMemberPath="DetailProperty"
Grid.Row="1"
/>
In this example I have created a public property in the code behind of the window that exposes a list of objects containing the Details collection.
public List<Master> MasterList { get; set; }
public class Master
{
public string MasterProperty { get; set; }
public List<Detail> Details { get; set; }
}
public class Detail
{
public string DetailProperty { get; set; }
}