Templates

List Picker for Xamarin provides the following templates:

  • ItemTemplate(DataTemplate): Defines the template used for displaying the list of items.
  • SelectedItemTemplate(DataTemplate): Specifies the template used for visualizing the selected item from the list.

In addition to this you can define the following templates provided from the RadPickerBase class:

  • PlaceholderTemplate(ControlTemplate): Defines the template visualized for the placeholder.
  • DisplayTemplate(ControlTemplate): Defines the template visualized when an item from the list is selected.

And using RadPickerBase.SelectorSettings property(of type Telerik.XamarinForms.Input.PickerPopupSelectorSettings) you can define the following templates:

  • HeaderTemplate(ControlTemplate): Defines what will be displayed inside the dialog(popup) header.
  • FooterTemplate(ControlTemplate): Defines what will be displayed inside the dialog(popup) footer.

This is the Visual Srtucture of the List Picker Templates:

List Picker Visual Structure

In addition the List Picker for Xamarin provides the following properties:

  • ItemsSource(IList): Specifies the collection used to generate the content of the list picker.
  • ItemLength(double): Defines the length of the items inside the list.
  • ItemSpacing(double): Defines the spacing between the items inside the list.
  • SelectedItem(object): Specifies the selected item of the list picker
  • DisplayMemberPath(string): Defines the path of the property which is to be displayed as DisplayString.

Example

Here is a sample List Picker definition:

<telerikInput:RadListPicker PlaceholderTemplate="{StaticResource placeholderTemplate}"
                            ItemTemplate="{StaticResource itemTemplate}"
                            SelectedItemTemplate="{StaticResource selectedItemTemplate}"
                            ItemLength="40"
                            ItemSpacing="4"
                            ItemsSource="{Binding Items}" 
                            DisplayMemberPath="Name"
                            x:Name="listPicker">
    <telerikInput:RadListPicker.BindingContext>
        <local:ViewModel/>
    </telerikInput:RadListPicker.BindingContext>
    <telerikInput:RadListPicker.SelectorSettings>
        <telerikInput:PickerPopupSelectorSettings HeaderTemplate="{StaticResource headerTemplate}"
                                                  FooterTemplate="{StaticResource footerTemplate}"/>
    </telerikInput:RadListPicker.SelectorSettings>
</telerikInput:RadListPicker>

and the templates definition in the page resources:

Item Template

<DataTemplate x:Key="itemTemplate">
    <Label Text="{Binding Population}" 
           BackgroundColor="LightYellow"
           HorizontalTextAlignment="Center" 
           VerticalTextAlignment="Center"/>
</DataTemplate>

SelectedItem Template

<DataTemplate x:Key="selectedItemTemplate">
    <Label Text="{Binding Name}" 
           BackgroundColor="LightBlue"
           HorizontalTextAlignment="Center" 
           VerticalTextAlignment="Center"/>
</DataTemplate>

Placeholder Template

<ControlTemplate x:Key="placeholderTemplate">
    <Label Text="Tap to open list picker" 
           FontAttributes="Bold" 
           TextColor="White"
           BackgroundColor="#B73562" 
           HeightRequest="50"
           VerticalTextAlignment="Center"
           HorizontalTextAlignment="Center">
        <Label.GestureRecognizers>
            <TapGestureRecognizer Command="{TemplateBinding ToggleCommand}" />
        </Label.GestureRecognizers>
    </Label>
</ControlTemplate>

Header Template

<ControlTemplate x:Key="headerTemplate">
    <Label Text="Select city:" 
           TextColor="White"
           FontSize="16"
           VerticalTextAlignment="Center"
           HorizontalTextAlignment="Center"
           BackgroundColor="#B73562"/>
</ControlTemplate>
<ControlTemplate x:Key="footerTemplate">
    <StackLayout Orientation="Horizontal" Spacing="0" HorizontalOptions="FillAndExpand" BackgroundColor="#B73562">
        <Button Text="Cancel" 
                TextColor="White"
                BackgroundColor="Transparent"
                Command="{TemplateBinding CancelCommand}" />
        <Button Text="OK" 
                TextColor="White"
                BackgroundColor="Transparent"
                Command="{TemplateBinding AcceptCommand}" />
    </StackLayout>
</ControlTemplate>

and a sample business model:

public class City
{
    public string Name { get; set; }
    public int Population { get; set; }
}

and the ViewModel:

public class ViewModel
{
    public ViewModel()
    {
        this.Items = new ObservableCollection<City>
        {
            new City { Name = "Tokyo", Population = 13929286 },
            new City { Name = "New York", Population = 8623000 },
            new City { Name = "London", Population = 8908081 },
            new City { Name = "Madrid", Population = 3223334 },
            new City { Name = "Los Angeles", Population = 4000000},
            new City { Name = "Paris", Population = 2141000 },
            new City { Name = "Beijing", Population = 21540000 },
            new City { Name = "Singapore", Population = 5612000 },
            new City { Name = "New Delhi", Population = 18980000 },
            new City { Name = "Bangkok", Population = 8305218 },
            new City { Name = "Berlin", Population = 3748000 },
        };
    }

    public ObservableCollection<City> Items { get; set; }
}

also you will need to add the following namespace:

xmlns:telerikInput="clr-namespace:Telerik.XamarinForms.Input;assembly=Telerik.XamarinForms.Input"

This is the result:

List Picker Templates

A sample Templates example can be found in the ListPicker/Features folder of the SDK Samples Browser application.

See Also

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