I have created an integer array in XAML as follows:
<x:Array Type="{x:Type sys:Int16}" x:Key="intervals">
<sys:Int16>1</sys:Int16>
<sys:Int16>2</sys:Int16>
<sys:Int16>3</sys:Int16>
</x:Array>
I have an integer property in ViewModel named Interval.
I am trying to bind this Interval property to the SelectedValue property of the ComboBox. However, the ComboBox does not show the selected value corresponding to the value of the Interval property. This is my ComboBox XAML code:
<ComboBox SelectedValue="{Binding Path=Interval}" Height="25" ItemsSource="{StaticResource intervals}" HorizontalContentAlignment="Center" Margin="78,47,237,128" Name="comboBox1" VerticalContentAlignment="Center" Width="85" />
Hi you should try SelectedItem instead of SelectedValue because for SelectedVlue you also have to provide SelectedValuePath.
public partial class MainWindow
{
public MainWindow()
{
InitializeComponent();
DataContext = this;
}
public Int16 Interval { get; set; }
private void Button_Click(object sender, RoutedEventArgs e)
{
var a = Interval;
}
}
<Window.Resources>
<x:Array Type="{x:Type sys:Int16}" x:Key="intervals">
<sys:Int16>1</sys:Int16>
<sys:Int16>2</sys:Int16>
<sys:Int16>3</sys:Int16>
</x:Array>
</Window.Resources>
<Grid x:Name="LayoutRoot">
<StackPanel>
<ComboBox SelectedItem="{Binding Path=Interval}" Height="25" ItemsSource="{StaticResource intervals}" HorizontalContentAlignment="Center" Margin="78,47,237,128" Name="comboBox1" VerticalContentAlignment="Center" Width="85" />
<Button Content="ok" Click="Button_Click"/>
</StackPanel>
</Grid>
I hope this will help.
You created an array of short values. Your Interval property should then also be of type short.
public short Interval { get; set; }
If you intended to use int as item type, you would have to use sys:Int32 as the array element type.
Also, you should bind the SelectedItem property. Although it works in your case, SelectedValue is meant to work in conjunction with SelectedValuePath.
<ComboBox SelectedItem="{Binding Path=Interval}" ... />
Related
In the following xaml fragment SessoList is a list of string ("M" and "F").
<ComboBox IsEditable="False" Margin="5" SelectedValue="{Binding Sesso}" ItemsSource="{Binding SessoList}" Width="40" Height="28"/>
The combobox works as expected and it is pre-populated reflecting the value of Sesso in the viewmodel.
The combobox selectable items are only two and fixed so I tried to simplify defining them in xaml:
<ComboBox IsEditable="False" Margin="5" SelectedValue="{Binding Sesso}" SelectedValuePath="{Binding Tag}" Width="40" Height="28" Name="Primo">
<ComboBoxItem Content="M" Tag="M" />
<ComboBoxItem Content="F" Tag="F" />
</ComboBox>
This combobox is capable of updating the viewmodel property sesso, but is not pre-populated with the correct value.
The following error is reported:
BindingExpression path error: 'Tag' property not found on 'object'
How can I successfully define the combobox items in xaml and have it display the right value based on SelectedValue databinding ?
Forgot to mention I'm using .Net 4.0
As I can understand, you want to define the ComboBox ItemsSource in XAML,
here is the solution that worked for me:
Xaml Window resources:
<Window.Resources>
<x:Array x:Key="Array" Type="{x:Type nirHelpingOvalButton:ComboObjectModel}">
<nirHelpingOvalButton:ComboObjectModel Content="M_Content" Tag="M_Tag"/>
<nirHelpingOvalButton:ComboObjectModel Content="F_Content" Tag="F_Tag"/>
</x:Array>
Xaml Combo:
<Grid>
<ComboBox IsSynchronizedWithCurrentItem="True" IsEditable="False" SelectedIndex="0" Margin="5" ItemsSource="{StaticResource Array}"
SelectedValue="{Binding Content, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"
SelectedValuePath="Tag" Width="90" Height="28" Name="Primo">
<i:Interaction.Behaviors>
<nirHelpingOvalButton:CustomComboSelectionBehavior/>
</i:Interaction.Behaviors>
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Content}"></TextBlock>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox></Grid>
View model combo SelectedValue binded property:
public string Content
{
get { return _content; }
set
{
_content = value;
OnPropertyChanged("Content");
}
}
List item Behavior Code:
protected override void OnAttached()
{
base.OnAttached();
AssociatedObject.Loaded += OnLoaded;
}
private void OnLoaded(object sender, RoutedEventArgs e)
{
var firstItem = AssociatedObject.ItemsSource.Cast<object>().FirstOrDefault();
AssociatedObject.SelectedItem = firstItem;
}
protected override void OnDetaching()
{
base.OnDetaching();
AssociatedObject.Loaded -= OnLoaded;
}
regards
What I need to find is when a textbox's value is changing or the dropdown's value changes inside my datatemplate item, I need to be notified in my ViewModel.cs.
So basically as a user edits a textbox inside the listbox, the viewmodel will be notified as the values are changing.
The reason is I need to go through all my Entries and update something as items inside the listbox's datatemplate change.
Any suggetion?
I have the following in my XAML.
<ListBox x:Name="EntriesListBox"
ItemsSource="{Binding Path=Entries}"
Grid.Row="1">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<ComboBox x:Name="EntriesPropertyName"
Width="215"
Margin="0,0,5,0"
SelectedItem="{Binding Path=Property, Mode=TwoWay}"
ItemsSource="{Binding Source={StaticResource DataContextProxy},Path=DataSource.EntityTypeProperties}" />
<TextBox x:Name="EntriesPropertyValue"
Width="215"
Margin="0,0,5,0"
Text="{Binding Path=Value, Mode=TwoWay, BindsDirectlyToSource=True}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
The following is in my VM (ViewModel.cs)
public ObservableCollection<Entry> Entries { get; set; }
The following is in my business object (Entry.cs)
public class Entry
{
public PropertyItem Property { get; set; }
public string Value { get; set; }
}
On your binding, set the UpdateSourceTrigger... Also implement INotifyPropertyChanged
Provided that you have setup your view model class properly (by implementing INotifyPropertyChanged), following is what you may want to do:
<TextBox x:Name="EntriesPropertyValue"
Width="215"
Margin="0,0,5,0"
Text="{Binding Path=Value, Mode=TwoWay, BindsDirectlyToSource=True, UpdateSourceTrigger=PropertyChanged}" />
This seems to work. Any reason not to do it this way?
private void EntriesPropertyValue_TextChanged(object sender, TextChangedEventArgs e)
{
(sender as TextBox).GetBindingExpression(TextBox.TextProperty).UpdateSource();
this.ViewModel.UpdateFinalQuery();
}
I am trying to declaratively bind a ComboBox within a DataGrid CellEditingTemplate using a ViewModel. The ComboBox is not being bound. What am I doing wrong?
XAML:
<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:ed="http://schemas.microsoft.com/expression/2010/drawing"
xmlns:data="clr-namespace:SilverlightApplication1"
mc:Ignorable="d"
x:Class="SilverlightApplication1.EmployeeDetail"
Width="640" Height="480">
<UserControl.Resources>
<data:EmployeeDetailsViewModel
x:Key="ViewModel"
d:IsDataSource="True" />
</UserControl.Resources>
<Grid x:Name="LayoutRoot" DataContext="{Binding Source={StaticResource ViewModel}}" Background="White">
<sdk:DataGrid ItemsSource="{Binding Employees,Mode=TwoWay}" AutoGenerateColumns="False" CanUserSortColumns="True" CanUserReorderColumns="True" CanUserResizeColumns="True" GridLinesVisibility="All" Height="317" HorizontalAlignment="Left" Margin="12,136,0,0" Name="EmployeesGrid" VerticalAlignment="Top" Width="605">
<sdk:DataGrid.Columns>
<!-- snipped from brevity -->
<sdk:DataGridTemplateColumn Header="Status">
<sdk:DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<TextBlock Text="{Binding EmployeeStatus.Description}" TextWrapping="Wrap"></TextBlock>
</DataTemplate>
</sdk:DataGridTemplateColumn.CellTemplate>
<sdk:DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<ComboBox ItemsSource="{Binding Path=EmployeeStatuses}" SelectedItem="{Binding EmployeeStatus, Mode=TwoWay}" />
</DataTemplate>
</sdk:DataGridTemplateColumn.CellEditingTemplate>
</sdk:DataGridTemplateColumn>
</sdk:DataGrid.Columns>
</sdk:DataGrid>
<TextBlock x:Name="SearchLabel" HorizontalAlignment="Left" Margin="12,95,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="106" Height="34"><Run FontWeight="Bold" Text="Search By Name: "/><Run FontSize="9.333" Text="(Last, First)"/></TextBlock>
<TextBox x:Name="SearchParam" HorizontalAlignment="Left" Margin="144,101,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="162"/>
<Button x:Name="SearchButton" Content="Search" HorizontalAlignment="Right" Margin="0,102,242,0" VerticalAlignment="Top" Width="75" Click="SearchButton_Click"/>
</Grid>
</UserControl>
VIEW MODEL:
using System.Collections.ObjectModel;
using SilverlightApplication1.EmployeeService;
using SilverlightApplication1.ViewModels;
namespace SilverlightApplication1
{
public class EmployeeDetailsViewModel : ViewModelBase
{
readonly IEmployeeServiceAgent _serviceAgent;
ObservableCollection<EmployeeStatus> _employeeStatuses { get; set; }
ObservableCollection<Employee> _employees { get; set; }
public EmployeeDetailsViewModel() : this(new EmployeeServiceAgent()) { }
public EmployeeDetailsViewModel(IEmployeeServiceAgent serviceAgent)
{
if (!IsDesignTime)
{
_serviceAgent = serviceAgent;
GetAllEmployees();
GetEmployeeStatuses();
}
}
public ObservableCollection<Employee> Employees
{
get { return _employees; }
set
{
if(_employees!=value)
{
_employees = value;
OnNotifyPropertyChanged("Employees");
}
}
}
public ObservableCollection<EmployeeStatus> EmployeeStatuses
{
get { return _employeeStatuses; }
set
{
if (_employeeStatuses != value)
{
_employeeStatuses = value;
OnNotifyPropertyChanged("EmployeeStatuses");
}
}
}
private void GetAllEmployees()
{
_serviceAgent.GetAll((s, e) => Employees = e.Result);
}
private void GetEmployeeStatuses()
{
_serviceAgent.GetEmployeeStatuses((s, e) => EmployeeStatuses = e.Result);
}
}
}
Update:
This seems wrong but I figured out how to get the binding working by re-referencing the ViewModel in the ItemSource Binding:
<ComboBox ItemsSource="{Binding Source={StaticResource ViewModel},Path=EmployeeStatuses}"
DisplayMemberPath="Description"
SelectedItem="{Binding EmployeeStatus, Mode=TwoWay}" />
However, a am now experiencing a problem where the SelectedItem is not bound! What am I doing wrong?
The problem is a common one that people run into. When you're in the data template of the column, you're no longer bound the the view model. At that point your data context is the EmployeeStatus object (which doesn't have an EmployeeStatuses property to bind to).
So to get the combobox binding to work you can use the ElementName=LayoutRoot to bind back up the tree to the root ViewModel.
Update: Here would be the full syntax for your binding:
{Binding DataContext.EmployeeStatuses, ElementName=LayoutRoot}
Update2: I've actually run into this as well and there is a workaround you have to implement to get the element name binding to work inside a datagrid.
If Bryant's solution does not work (in SL4), use static resources. See this link: http://blog.digitaltools.com/post/2011/05/06/Binding-a-Datagride28099s-ComboBox.aspx
Or, by creating the static resource in xaml: http://forums.silverlight.net/post/370135.aspx
I have a ListBox whose ItemsSource is bound to a list of objects. The Listbox has a ItemTemplate with a DataTemplate containing a TextBlock. The textblock's Text is bound to the object's Name property (i.e. Text="{Binding Name}").
I would like to provide a radio button to show different views of the same list. For example allow a user to toggle between the Name property and an ID property.
I found a SO answer for this at 2381740 but I also have border and a textbox style set in data template (see code below).
Is there anyway to just reset the Textblock binding? I don't want to have to recreate the entire datatemplate. Actually I'm not even sure how to do that, is there an easy way to translating xaml to code?.
Thanks
Cody
<DataTemplate>
<Border Margin="0 0 2 2"
BorderBrush="Black"
BorderThickness="3"
CornerRadius="4"
Padding="3">
<TextBlock Style="{StaticResource listBoxItemStyle}"
Text="{Binding Name}" />
</Border>
</DataTemplate>
Wallstreet Programmer's solution works well for you because you are using radio buttons. However there is a more general solution that I thought I should mention for future readers of this question.
You can change your DataTemplate to use plain "{Binding}"
<DataTemplate x:Key="ItemDisplayTemplate">
<Border ...>
<TextBlock ...
Text="{Binding}" />
</Border>
</DataTemplate>
Then in code you don't have to recreate a full DataTemplate. All you have to do is recreate this:
<DataTemplate>
<ContentPresenter Content="{Binding Name}" ContentTemplate="{StaticResource ItemDisplayTemplate}" />
</DataTemplate>
which is easy:
private DataTemplate GeneratePropertyBoundTemplate(string property, string templateKey)
{
var template = FindResource(templateKey);
FrameworkElementFactory factory = new FrameworkElementFactory(typeof(ContentPresenter));
factory.SetValue(ContentPresenter.ContentTemplateProperty, template);
factory.SetBinding(ContentPresenter.ContentProperty, new Binding(property));
return new DataTemplate { VisualTree = factory };
}
This is particularly convenient if you have many properties, even in your radio button example.
Just make it simple for yourself and use two textblocks and hide one of them.
XAML:
<Window x:Class="Test.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Height="300" Width="300">
<Window.Resources>
<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" />
</Window.Resources>
<StackPanel>
<RadioButton Name="nameRadioBtn" Content="Name" IsChecked="True"/>
<RadioButton Name="lengthRadioBtn" Content="Length" />
<ListBox
ItemsSource="{Binding Path=Items}">
<ListBox.ItemTemplate>
<DataTemplate>
<Border BorderBrush="Red" BorderThickness="1">
<Grid>
<TextBlock
Text="{Binding .}"
Visibility="{Binding Path=IsChecked, ElementName=nameRadioBtn,
Converter={StaticResource BooleanToVisibilityConverter}}" />
<TextBlock
Text="{Binding Path=Length}"
Visibility="{Binding Path=IsChecked, ElementName=lengthRadioBtn,
Converter={StaticResource BooleanToVisibilityConverter}}" />
</Grid>
</Border>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
</Window>
Code behind:
using System.Collections.Generic;
using System.Windows;
namespace Test
{
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
DataContext = this;
}
public IEnumerable<string> Items
{
get
{
return new List<string>() {"Bob", "Sally", "Anna"};
}
}
}
}
You can also use a value converter to pick any property of your data object. You will need to bind to the whole object instead of individual properties. If your data object implements INotifyPropertyChanged then this solution will not work for you.
XAML
<Window x:Class="Test.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:Test="clr-namespace:Test"
Height="300" Width="300">
<Window.Resources>
<Test:PropertyPickerConverter x:Key="PropertyPickerConverter" />
</Window.Resources>
<StackPanel>
<RadioButton Content="Name" Click="OnRadioButtonClick" IsChecked="True"/>
<RadioButton Content="Length" Click="OnRadioButtonClick" />
<ListBox
ItemsSource="{Binding Path=Items}"
Name="_listBox">
<ListBox.ItemTemplate>
<DataTemplate>
<Border BorderBrush="Red" BorderThickness="1">
<StackPanel>
<TextBlock
Text="{Binding ., Converter={StaticResource PropertyPickerConverter}}" />
</StackPanel>
</Border>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
</Window>
code behind:
using System.Collections.Generic;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
namespace Test
{
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
_propertyPickerConverter = FindResource("PropertyPickerConverter") as PropertyPickerConverter;
_propertyPickerConverter.PropertyName = "Name";
DataContext = this;
}
public IEnumerable<string> Items
{
get
{
return new List<string>() {"Bob", "Sally", "Anna"};
}
}
private void OnRadioButtonClick(object sender, RoutedEventArgs e)
{
_propertyPickerConverter.PropertyName = (sender as RadioButton).Content as string;
_listBox.Items.Refresh();
}
private PropertyPickerConverter _propertyPickerConverter;
}
public class PropertyPickerConverter : IValueConverter
{
public string PropertyName { get; set; }
#region IValueConverter Members
public object Convert(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
string item = value as string;
switch (PropertyName)
{
case "Name": return item;
case "Length": return item.Length;
default: return null;
}
}
public object ConvertBack(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new System.NotImplementedException();
}
#endregion
}
}
Near total WPF noob. So I hooked up a combobox to have checkboxes using the following item template:
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox Checked="{Binding IsSelected}"
Width="20" Name="chkDayName" Click="chkDayName_Click"/>
<TextBlock Text="{Binding DayOfWeek}"
Width="100" Name="txtDayName" />
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
On the actual event of a person clicking a checkbox, i catch the event in chkDayName_Click method. I have the following questions:
How do I find out values of the corresponding TextBlock in the item template?
How do i find out the index of the item that was clicked?
Is there a way to get to the parent?
Thanks.
If I understand it you want to know which combobox items are checked? You can use the chkDayName_Click for that and add the name of the day as Tag of the CheckBox. This feels very Winforms. In WPF you normally let your databinding handle functionality like this. Below is some code that will display selected item in a textbox and a list of checked weekdays.
XAML:
<Window x:Class="DayComboBoxDemo.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">
<Window.Resources>
<CollectionViewSource x:Key="checkedWeekdays" Source="{Binding Path=WeekDays}" Filter="IsCheckedFilter" />
</Window.Resources>
<StackPanel>
<ComboBox
ItemsSource="{Binding Path=WeekDays}"
SelectedItem="{Binding Path=SelectedWeekDay}">
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox
IsChecked="{Binding Path=IsChecked}"
Width="20" Click="chkDayName_Click"/>
<TextBlock
Text="{Binding DayOfWeek}" Width="100" />
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
<TextBlock Text="{Binding Path=SelectedWeekDay.DayOfWeek}" />
<ListBox
DisplayMemberPath="DayOfWeek"
ItemsSource="{Binding Source={StaticResource checkedWeekdays}}" />
</StackPanel>
</Window>
Code behind:
using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Data;
namespace DayComboBoxDemo
{
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
List<WeekDay> weekDays = new List<WeekDay>();
foreach (DayOfWeek dayOfWeek in System.Enum.GetValues(typeof(DayOfWeek)))
{
weekDays.Add(new WeekDay() { DayOfWeek = dayOfWeek });
}
WeekDays = weekDays;
_checkedWeekdays = FindResource("checkedWeekdays") as CollectionViewSource;
DataContext = this;
}
public IEnumerable<WeekDay> WeekDays { get; set; }
public WeekDay SelectedWeekDay
{
get { return (WeekDay)GetValue(SelectedWeekDayProperty); }
set { SetValue(SelectedWeekDayProperty, value); }
}
public static readonly DependencyProperty SelectedWeekDayProperty =
DependencyProperty.Register("SelectedWeekDay",
typeof(WeekDay),
typeof(Window1),
new UIPropertyMetadata(null));
private void chkDayName_Click(object sender, RoutedEventArgs e)
{
_checkedWeekdays.View.Refresh();
}
private void IsCheckedFilter(object sender, FilterEventArgs e)
{
WeekDay weekDay = e.Item as WeekDay;
e.Accepted = weekDay.IsChecked;
}
private CollectionViewSource _checkedWeekdays;
}
public class WeekDay
{
public DayOfWeek DayOfWeek { get; set; }
public bool IsChecked { get; set; }
}
}
You can try ComboBox's SelectedIndex or SelectedValue to tell the SelectedItem. In the MVVM fashion, you can have a two-way binding between SelectedIndex and one of you ViewModel properties.