I know Autocompleteboxes generally are for binding items and selected items.
But what If I enter text in it and the item doesn't exist. And I want to bind it to a string variable is that possible?
For example
<telerik:RadAutoCompleteBox Text="{Binding Value}"
MVVM side
public string Value {get; set;}
Use SearchText property instead, e.g.:
<telerik:RadAutoCompleteBox
x:Name="acb"
SearchText="{Binding SearchText, Mode=TwoWay}"
ItemsSource="{Binding Items}" />
Don't forget to implement INotifyPropertyChanged interface to sync changes between view and viewmodel.
Related
I have a class PricingData and PricingSchedule. Where PricingSchedule is a List<> inside PricingData class. I want to bind data of this class to UWP controls.
Sample code is available to download here : https://github.com/jigneshdesai/SampleOfBindingIssue1.git
How Code looks: i have a start page(mainpage) that hosts ListView control, Listview has PricingUserControl within it. PricingUserControl looks like this
<TextBlock x:Name="lblPriceHeader" Text="{Binding PricingTitle}" Margin="0,0,50,0" />
<ComboBox x:Name="cbPriceValueList" ItemsSource="{x:Bind dpl}" DisplayMemberPath="PriceValue" SelectedValuePath="PriceValue" SelectedValue="{Binding DisplayPricing}" />
<ListView x:Name="lbPriceChangeSchedule" ItemsSource="{Binding PricingScheduleList}">
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel>
<StackPanel Orientation="Horizontal">
<ComboBox x:Name="cbSchedulePriceValueList" ItemsSource="{x:Bind dpl}" DisplayMemberPath="PriceValue" SelectedValuePath="PriceValue" />
<TextBlock Text="{Binding SchedulePricingTimeZone }" />
</StackPanel>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
What i want to achieve: Combobox should populate a list of values (eg. 1USD, 2USD, 3USD etc.). Then when you provide List of records from database, the listbox will repeat PricingUserControl and combobox within it should set its value property (SelectedValue) as per record.
Issue:
ComboBox x:Name="cbPriceValueList" uses x:bind dpl where dpl is a local variable of PricingUserControl. It populates the list properly. The trouble is ComboBox x:Name="cbSchedulePriceValueList" it also has x:bind dpl but during compilation it display error "Invalid binding path 'dpl' : Property 'dpl' not found on type 'DataTemplate'."
I am wondering why x:bind dpl does not work at this point. ?
I have now realized that your problem is in fact that you need to reach to a Page property from within the DataTemplate, so here is a updated answer.
You cannot use x:Bind if you need to access an outside element's property from within a DataTemplate. Instead, you can use classic {Binding} expression. First add a name to your page:
<Page
...
x:Name="Page">
And now refer to this name from within the DataTemplate:
<ComboBox
x:Name="cbSchedulePriceValueList"
ItemsSource="{Binding ElementName=Page, Path=dpl}"
DisplayMemberPath="PriceValue"
SelectedValuePath="PriceValue" />
Original answer
To be able to use x:Bind inside of a DataTemplate, you must specify the data type the individual items of the control will have, using x:DataType. Suppose your PricingScheduleList is a List<MyApp.Models.MyType>, then you will first need to add this XML namespace to the <Page> element:
xmlns:models="using:MyApp.Models"
And then set the x:DataType attribute as follows:
<DataTemplate x:DataType="models:MyType">
...
</DataTemplate>
You can confirm this works by the fact that IntelliSense should now suggest you the properties of MyType when you start writing the x:Bind expression.
By checking your code, the reason why SelectedValue does not take effect is when you choose the item from ComboBox, you didn't notify your DisplayPricing to change. So you need to implement INotifyPropertyChanged interface in your PricingData. Do the same behavior in PricingSchedule.
public class PricingData : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged = delegate { };
......
public string DisplayPricing
{
get => $"{PricingValue} {PricingCurrency}";
set
{
var sp = value.Split(' ');
PricingValue = sp.First();
PricingCurrency = sp.Last();
OnPropertyChanged();
}
}
public void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
PScheduleUserControl.xaml:
<ComboBox x:Name="cbPriceValueList" ItemsSource="{x:Bind myList}" DisplayMemberPath="PriceValue" SelectedValuePath="PriceValue" SelectedValue="{Binding DisplayPricing,Mode=TwoWay}" />
I implemented editable ListBox items like it is posted in this answer Inline editing TextBlock in a ListBox with Data Template (WPF)
.
But the new value does not get updated in the ItemsSource object of my ListBox.
This is the XAML:
<ListBox Grid.Row="2" Name="ds_ConfigProfiles" ItemsSource="{Binding ConfigProfiles}" SelectedItem="{Binding ActiveConfigProfile}" IsSynchronizedWithCurrentItem="True" Panel.ZIndex="-1">
<ListBox.ItemTemplate>
<DataTemplate>
<!-- TODO: this is meant for allowing edit of the profile names, but the new name does not get stored back to ConfigProfiles -->
<local:TextToggleEdit Text="{Binding Path=., Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" MinWidth="40" Height="23" />
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
This is the ConfigProfiles property in the view model:
/// <summary>Configuration profiles that were found in the active storage path</summary>
public ObservableCollection<string> ConfigProfiles { get; private set; } = new ObservableCollection<string>();
Did I understand something wrong?
May it be the reason, that the items source is of type ObservableCollection<string> instead of ObservableCollection<ProperClassImplementation> (which is of legacy reasons).
I am relatively new to WPF and am out of ideas on how to debug this.
May it be the reason, that the items source is of type ObservableCollection<string> instead of ObservableCollection<ProperClassImplementation> (which is of legacy reasons).
Yes, exactly. You can't modify a string since it is immutable. You need to bind to a string property of a class which means that you need to replace the ObservableCollection<string> with an ObservableCollection<ProperClassImplementation>.
I am afraid the binding engine won't replace the string in the ObservableCollection<string> with a new string for you if that's what you had hoped for.
I am trying to bind a ListBox to another ListBox within the same window. The left hand sided Listbox has data in it that one can select. But I want a user to be able to click on the item(s) in the left hand listbox and those same item(s) would be displayed in the other listbox on the right hand side.
EDITED: Of course you can bind a UI property to another UI property (Dependency Property actually) using ElementName, but I recommend to bind the properties to one view model. See a simplified example below.
View model:
public ObservableCollection<ItemObject> Items { get; set; }
public ObservableCollection<ItemObject> SelectedItems { get; set; }
Left:
<ListBox ItemsSource="{Binding Items}" SelectedItems="{Binding SelectedItems}" />
(Note that there is no SelectedItems dependency property actually. See question like: Select multiple items from a DataGrid in an MVVM WPF project)
Right:
<ListBox ItemsSource="{Binding SelectedItems}" />
This works fine. Furthermore, with this approach, the list on the right hand can be customized with ease (eg order, filter, ... by using CollectionView).
private ICollectionView _collectionView;
private ICollectionView _CollectionView {
get { return _collectionView
?? (_collectionView = CollectionViewSource.GetDefaultView(SelectedItems)); }
}
public ICollectionView FilteredItems {
get { _CollecitionView.Filter(...); }
}
<ListBox ItemsSource={"Binding FilteredSelectedItems"} />
Such an MVVM approach is sometimes laborious, but eventually found as beneficial.
You name the first listbox, then any other control on the xaml will bind to that control using it's name in the ElementName attribute of the binding.
For example there are two listboxes and one text box. The top listbox has multiselections and those selection(s) are shown on the lower listbox. While the textbox only gets the first item selected.
<StackPanel Orientation="Vertical">
<StackPanel.Resources>
<converters:PathToFilenameConverter x:Key="FilenameConverter" />
<x:Array x:Key="FileNames" Type="system:String">
<system:String>C:\Temp\Alpha.txt</system:String>
<system:String>C:\Temp\Beta.txt</system:String>
<system:String>C:\Temp\Gamma.txt</system:String>
</x:Array>
</StackPanel.Resources>
<ListBox Name="lbFiles"
SelectionMode="Multiple"
ItemsSource="{StaticResource FileNames}"
Margin="10"/>
<ListBox ItemsSource="{Binding SelectedItems, ElementName=lbFiles }" Margin="10" />
<TextBlock Text="{Binding SelectedItem,
ElementName=lbFiles,
Converter={StaticResource FilenameConverter}}"
Margin="10" />
</StackPanel>
Note...the code is binding using the SelectedItems property for the lower list box and not SelectedItem used by the TextBlock.
As an aside, another answer has the use of an ObservableCollection, that is not needed unless the array is dynamically changing; otherwise any array can be used. Depending on loading, say from a VM, it may need to adheres to the INotifyPropertyChanged.
I have a list of notifications:
public List<Notification> Notifications { get; set; }
A ListBox in my UI binds to this list:
<ListBox ItemsSource="{Binding Notifications}" DisplayMemberPath="ServiceAddress" Name="NotificationsList"/>
In my UI, I also have this TextBox:
<TextBox Name="MatchWindowTextBox"/>
MatchWindow is a property in Notification objects...so I can access it like this from the above list: Notifications[SomeIndex].MatchWindow. Anyways, when someone changes the selection on the ListBox, this effectively selects a different Notification...so is there some way to bind my TextBox to the selected notification's MatchWindow property?
one quick way is to use an ElementName binding:
<TextBox Text="{Binding SelectedItem.MatchWindow,
ElementName=NotificationsList}"/>
However, a better approach would be to create a SelectedItem property of type Notification in the ViewModel and bind to that instead:
<ListBox ItemsSource="{Binding Notifications}"
SelectedItem="{Binding SelectedNotification}"/>
<!-- ... -->
<TextBox Text="{Binding SelectedNotification.MatchWindow}"/>
I'm using silverlight framework 4: I'm trying to list my items in a generic list to a listbox control: But the only data a receive is the classname itself.
lsBox => the listbox control
lsTags => generic type
My question is: how can I add my items in the generic list, to the listbox control?
my code is:
lsBox.ItemsSource = lsTags;
You can use DisplayMemberPath and SelectedValuePath properties of your ListBox control to tell ListBox which property's value should be displayed for every item and which property should be used for determening ListBox.SelectedValue property. Or use ListBox.ItemTemplate to display a complex data like this:
<ListBox x:Name="usersInGroupLBox">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<CheckBox IsChecked="{Binding IsActive, Mode=TwoWay}" />
<TextBlock Text="{Binding User.UserName}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Do not forget, you can use only public properties for binding. Check you class Tag.
The default behavior of ListBox (and most other controls) for displaying user types is to call the ToString() method. The default behavior of that is to display the class name.
What you should do depends on what you want to display, but if it's something simple like displaying the value of the Name property, just set the DisplayMemberPath property:
<ListBox Name="lsBox" DisplayMemberPath="Name" />