I have a question concerning data binding with tabs.
I have the following xaml code:
<Window x:Class="SuperAtomsController.GUI.windowAnalog"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="windowAnalog" Height="900" Width="1400"
DataContext="{Binding RelativeSource={RelativeSource self}}">
<Grid>
<TabControl Height="459" HorizontalAlignment="Left" Margin="188,278,0,0" Name="tabControl1" ItemsSource="{Binding Path=model.sequences}" VerticalAlignment="Top" Width="883">
</TabControl>
</Grid>
</Window>
And the code behind:
public partial class windowAnalog : Window
{
public Data model;
public windowAnalog(Data model)
{
this.model = model;
InitializeComponent();
}
}
But with this nothing appears in the tabcontrol (model.sequences is of the type ObservableCollection<>). If remove the itemssource in xaml and add the following in the c# code tabControl1.ItemsSource = model.sequences; after the InitializeComponent(); it works fine. What am I missing?
Clearly your binding isn't resolving, check your debug output window for helpful diagnostic messages.
I can't recall but I think model may need to be a property instead of a field for WPF property path to work. Otherwise maybe it was a problem with the DataContext. You coudl try doing this.DataContext = this to your constructor before InitializeComponent() instead of your DataContext xaml.
Related
This is a follow up question related to a control that needs to intercept when common control properties changes (Inherit UserControl and hooking up to basic property events).
When any base property changes (foregound, font style, size...), I need to invalidate the canvas and redraw the content.
I've ended up with calling this method inside the UserControl constructor:
RegisterPropertyChangedCallback(DependencyProperty dp, DependencyPropertyChangedCallback callback);
For example:
RegisterPropertyChangedCallback(ForegroundProperty, OnPropertyChanged);
RegisterPropertyChangedCallback(FontFamilyProperty, OnPropertyChanged);
RegisterPropertyChangedCallback(FontSizeProperty, OnPropertyChanged);
Inside OnPropertyChanged I proceed to rewire some property and invalidate the canvas in order to update the picture.
The control is inside a DataTemplate referenced by a Pivot (PivotHeaderTemplate). The default Foreground is the unselected status (semi-transparent SystemControlForegroundBaseMediumBrush) and should get the default "white" when selected (SystemControlHighlightAltBaseHighBrush).
The control Foreground property is applied by a template, and according to the live tree it's updating, but OnPropertyChanges is called only the first time.
For example, the Pivot has 2 views: the first one starts selected and is white, and the second is unselected and is "grayish".
If I change the selection, the view changes, the Foreground property changes accordingly on both controls but OnPropertyChanges is not called, and my canvas doesn't change (because the invalidation logic is inside that method).
[UPDATE: as a workaround, I used the event LayoutUpdated to check what changed.]
For a test project, create a new UWP XAML project a new MyCanvas UserControl.
MyCanvas.xaml:
<UserControl x:Class="InheritControlProperty.Controls.MyCanvas"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:InheritControlProperty.Controls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Canvas x:Name="content" Width="50" Height="50"/>
</UserControl>
MyCanvas.xaml.cs
using System;
using Windows.UI;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media;
namespace InheritControlProperty.Controls
{
public sealed partial class MyCanvas : UserControl
{
private Color Value
{
get { return (Foreground as SolidColorBrush)?.Color ?? Colors.Black; }
}
public MyCanvas()
{
InitializeComponent();
RegisterPropertyChangedCallback(ForegroundProperty, OnPropertyChanged);
}
private void OnPropertyChanged(DependencyObject sender, DependencyProperty dp)
{
content.Background = new SolidColorBrush(Value);
//Logic for more complex canvas management here
}
}
}
MainPage.xaml
<Page x:Class="InheritControlProperty.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:InheritControlProperty"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:cntr="using:InheritControlProperty.Controls"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Page.Resources>
<DataTemplate x:Key="NameTemplate">
<Grid BorderBrush="Orange" BorderThickness="2">
<cntr:MyCanvas Width="100" Height="50"/>
<!-- Try using Foreground="Red" -->
</Grid>
</DataTemplate>
</Page.Resources>
<Pivot Margin="20" HeaderTemplate="{StaticResource NameTemplate}">
<PivotItem>Item 1</PivotItem>
<PivotItem>Item 2</PivotItem>
</Pivot>
</Page>
I am setting the datacontext of my xaml page to a viewmodel passed in to the construrctor. My viewmodel has an object called Item, which has a property called Category.
public DataEntry(DEViewModel vm)
{
InitializeComponent();
this.vm = vm;
this.DataContext = this.vm;
}
I am trying to bind to the ViewModel.Item.Category property like so:
<TextBox Name="txtCategory" Text="{Binding Path=Item.Category, Mode=TwoWay}" />
This does not work. If I set the datacontext to vm.Item, and bind to Category it works.
Any ideas on how to bind to a property that is hanging off of an object on the viewmodel?
Thanks, Terrence
Do it like this,
<TextBox Name="txtCategory"
Text="{Binding Category, Mode=TwoWay}"
DataContext="{Binding Item}" />
The reason it was not working is because it will only look at property notifications for the DataContext, so just set the local DataContext for the control to Item and the control will handle property notifications for Item.
Thanks,
Alex.
I have been messing with something that works in the code behind but when I try and bind to a MVVM , nothing displays. First I will show the code behind, then MVVM ( same xaml ). I want to use MVVM and not code behind.
Code Behind (works):
var loadOp = ctx.Load<GateBlox.Web.Models.Structure>(ctx.GetStructuresQuery());
loadOp.Completed += (s, e) => { _treeView.ItemsSource = loadOp.Entities.Where(struc => !struc.StructureParentFK.HasValue); };
XAML
<Grid x:Name="LayoutRoot">
<sdk:TreeView x:Name='_treeView' DataContext='{StaticResource ViewModel}'>
<sdk:TreeView.ItemTemplate>
<sdk:HierarchicalDataTemplate ItemsSource='{Binding Children}'>
<TextBlock Text='{Binding StructureName}' />
</sdk:HierarchicalDataTemplate>
</sdk:TreeView.ItemTemplate>
</sdk:TreeView>
</Grid>
MVVM (doesnt bind)
private LoadOperation<Structure> _loadStructures;
private StructureContext _structureContext;
private IEnumerable<Structure> _structures;
public IEnumerable<Structure> Structures
{
get { return this._structures; }
set { this._structures = value; RaisePropertyChanged("Structures"); }
}
public StructuresViewModel()
{
if (!DesignerProperties.IsInDesignTool)
{
_structureContext = new StructureContext();
_loadStructures = _structureContext.Load(_structureContext.GetStructuresQuery().Where (p=> ! p.StructureParentFK.HasValue));
_loadStructures.Completed += new EventHandler(_loadStructures_Completed);
}
}
void _loadStructures_Completed(object sender, EventArgs e)
{
this.Structures = _loadStructures.Entities;
}
Have your checked that you are not getting a binding expression error in the output? You are binding the items source of the data template to a property named Children, but your view model exposes a data source named Structures.
Also, in your working example, you are setting the ItemsSource of the TreeView, but in your MVVM XAML you are setting the ItemsSource of your data template. Is there an inconsistency between what ItemsSource you need to set/bind to?
You might also consider using a collection data source that implements the INotifyCollectionChanged interface (ObservableCollection or expose the binding source as a ICollectionView that uses a PagedCollectionView).
I recommend you take a look at this information about data binding in MVVM, as it provides excellent guidance on setting up data sources in your view models.
You are not setting the ItemsSource for your TreeView. I think your xaml should look something like this:
<Grid x:Name="LayoutRoot">
<sdk:TreeView x:Name='_treeView' DataContext='{StaticResource ViewModel}'
ItemsSource="{Binding Structures}">
<sdk:TreeView.ItemTemplate>
<sdk:HierarchicalDataTemplate ItemsSource='{Binding Children}'>
<TextBlock Text='{Binding StructureName}' />
</sdk:HierarchicalDataTemplate>
</sdk:TreeView.ItemTemplate>
</sdk:TreeView>
</Grid>
Hope this helps :)
I almost have it working now. I took a different approach and went with a HeirarchicalDataTemplate. At the moment the data is showing but not correctly: The child1 record is shwoing up as a parent as well.
Parent1(level1)
Parent2(level1)
Child1(level2)
Child1(level1)
<navigation:Page x:Class="GateBlox.Views.Structure"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"
d:DesignWidth="640"
d:DesignHeight="480"
Title="Structure Page"
xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"
xmlns:viewmodel="clr-namespace:GateBlox.ViewModels">
<UserControl.Resources>
<viewmodel:StructuresViewModel x:Key='ViewModel'>
</viewmodel:StructuresViewModel>
</UserControl.Resources>
<Grid x:Name="LayoutRoot"
DataContext='{StaticResource ViewModel}'>
<Grid.Resources>
<sdk:HierarchicalDataTemplate x:Key="ChildTemplate"
ItemsSource="{Binding Path=Parent}">
<TextBlock FontStyle="Italic"
Text="{Binding Path=StructureName}" />
</sdk:HierarchicalDataTemplate>
<sdk:HierarchicalDataTemplate x:Key="NameTemplate"
ItemsSource="{Binding Path=Children}"
ItemTemplate="{StaticResource ChildTemplate}">
<TextBlock Text="{Binding Path=StructureName}"
FontWeight="Bold" />
</sdk:HierarchicalDataTemplate>
</Grid.Resources>
<sdk:TreeView x:Name='treeView'
Width='400'
Height='300'
ItemsSource='{Binding Structures}'
ItemTemplate='{StaticResource NameTemplate}'>
</sdk:TreeView>
</Grid>
using System;
using System.Collections.ObjectModel;
using GateBlox.Web.Models;
using System.ServiceModel.DomainServices.Client;
using GateBlox.Web.Services;
using GateBlox.Helpers;
using System.ComponentModel;
using System.Collections.Generic;
namespace GateBlox.ViewModels
{
public class StructuresViewModel : ViewModelBase
{
private LoadOperation<Structure> _loadStructures;
private StructureContext _structureContext;
private ObservableCollection<Structure> _structures;
public ObservableCollection<Structure> Structures
{
get { return this._structures; }
set { this._structures = value; RaisePropertyChanged("Structures"); }
}
public StructuresViewModel()
{
if (!DesignerProperties.IsInDesignTool)
{
_structureContext = new StructureContext();
_loadStructures = _structureContext.Load(_structureContext.GetStructuresQuery());
_loadStructures.Completed += new EventHandler(_loadStructures_Completed);
}
}
void _loadStructures_Completed(object sender, EventArgs e)
{
this.Structures = IEnumerableConverter.ToObservableCollection(_loadStructures.Entities);
}
}
}
Hi guys I am working with SL4 and MVVM application actually i am stuck some where i might be doing some thing wrong thats why need your help, here is my scenario
//suodo code
public class EmployeeModel
{
//code
Public List<Shifts> Employeeshifts{get;set;}
}
public class ShiftModel
{
//code
}
Viewmodel for main page
public class MainVM
{
MainVM()
{
EmployeeList = DateFromSomeService;
}
Public List<Employees> EmployeeList{get;set}
Public DelegateCommand ClickBindingCommand{get;set;}
}
MainPage.xaml
<ItemsControl ItemSource={Binding EmployeeList}>
<ItemTemplate>
<DataTemplate>
<controls:EmployeeControl/>
</DataTemplate>
</ItemTemplate>
</ItemsControl>
Employeecontro.xaml
<ItemsControl ItemSource={Binding EmployeeShifts}>
<ItemTemplate>
<DataTemplate>
<controls:ShiftControl Click={Binding ClickBindingCommand}/>//here is problem this command is in mainviewmodel
</DataTemplate>
</ItemTemplate>
</ItemsControl>
MainPage.cs
this.DataContext = new MainVM();
ClickBindingCommand is defined in main VM but it is bound within shift control and shiftcontrol's data context is shift class which is my model class. If I declare this command in my shift model class than it works, means if I click on shift control this property is called but I dont want this because I want it in my main view model, where am I wrong?
Should I declare it in my shift model class but in this way i will bind directly my model to my view?
Use a DataContextProxy or a RelativeSource Binding. This will allow your Command to bind/fire on your MainViewModel.
Another alternative is to use the Caliburn Micro framework. You can then attach an action to your button in the child and click events will bubble up to the parent.
This "toolkit" offers an implementation of FindAncestor in silverlight. Try this:
http://blog.thekieners.com/2010/09/08/relativesource-binding-with-findancestor-mode-in-silverlight/
I ran into this same issue and what fixed it for me was to name my UserControl then reference that name in the binding.
Here is the syntax:
{Binding ElementName=SomeTextBox, Path=Text}
Bind to the “Text” property of the element XAML
element with name=”SomeTextBox” or x:Name=”SomeTextBox”.
So here is my user control:
<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Class="SupportReports.Workflow.Portfolio.PortfolioManager"
mc:Ignorable="d"
Name="PortfolioManagerControl"
>
And here is the nested dataTemplate that binds to my command in my main view model
<cmd:EventToCommand Command="{Binding ElementName=PortfolioManagerControl, Path=DataContext.PortfolioManagerProjectSelectedCommand}" CommandParameter="{Binding Text, ElementName=ProjectName}" />
I have a form with some validations set in entity metadata class. and then binding entity instance to UI by VM. Something as below:
Xaml like:
<Grid x:Name="LayoutRoot">
<StackPanel VerticalAlignment="Top">
<input:ValidationSummary />
</StackPanel>
<TextBox Text="{Binding Name, Mode=TwoWay}" />
<ComboBox x:Name="xTest" ItemsSource="{Binding MyList}"
SelectedItem="{Binding MyItem,Mode=TwoWay,
DisplayMemberPath="MyName"
ValidatesOnDataErrors=True,
ValidatesOnNotifyDataErrors=True,
ValidatesOnExceptions=True,
NotifyOnValidationError=True,UpdateSourceTrigger=Explicit}" />
</Grid>
Code-behind like:
public MyForm()
{
InitializeComponent();
this.xTest.BindingValidationError +=new EventHandler<ValidationErrorEventArgs>((s,e)=>{
BindingExpression be = this.xTest.GetBindingExpression(ComboBox.SelectedItemProperty);
be.UpdateSource();
if (e.Action == ValidationErrorEventAction.Added)
((ComboBox)s).Foreground = new SolidColorBrush(Colors.Red);
});
}
Metadata like:
[Required]
public string Name { get; set; }
[RequiredAttribute]
public int MyItemID { get; set; }
But when running the app, I got nothing display in valudationSummary.
For CombBox, even there is error, looks like BindingValidationError event is never fired.
How to resolve it?
Why are you using an Explicit UpdateSourceTrigger?
Silverlight validation happens inside the binding framework, when the binding is updating the source object. The way you have this, there won't be a binding validation error because you never tell the binding to update the source object. Well, actually you do, but it happens inside the validation error event handler. You've written chicken-and-egg code.
Remove your UpdateSourceTrigger on your binding or set it to Default.
Remove the explicit call to BindingExpression.UpdateSource.
Remove setting the ComboBox foreground to red - you are using NotifyOnValidationError=True, which eliminates any need to manually color the control.
Remove the DisplayMemberPath from the binding
So your XAML:
<Grid x:Name="LayoutRoot">
<StackPanel VerticalAlignment="Top">
<input:ValidationSummary />
<ComboBox x:Name="xTest" ItemsSource="{Binding MyList}"
SelectedItem="{Binding MyItem,
Mode=TwoWay,
ValidatesOnDataErrors=True,
ValidatesOnNotifyDataErrors=True,
ValidatesOnExceptions=True,
NotifyOnValidationError=True}" />
</StackPanel>
</Grid>
And your code:
public MyForm()
{
InitializeComponent();
// you don't need anything here to have the validations work
}