Templates

The TemplatedPicker for .NET MAUI provides the following templates:

  • SelectorTemplate(ControlTemplate)—Defines the template used for displaying the selector of the picker.

  • PlaceholderTemplate(ControlTemplate)—Defines the template visualized for the placeholder.

  • DisplayTemplate(ControlTemplate)—Defines the template visualized when an item from the selector was picked.

When you use the 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.

Example

The following example demonstrates how to define the templates.

  1. Define a sample TemplatedPicker:

    <telerik:RadTemplatedPicker x:Name="picker"
                              SelectedValue="{Binding FromCity, Mode=TwoWay}"
                              DisplayMemberPath="Name"
                              SelectorTemplate="{StaticResource SelectorTemplate}">
      <telerik:RadTemplatedPicker.PopupSettings>
          <telerik:PickerPopupSettings HeaderTemplate="{StaticResource HeaderTemplate}"/>
      </telerik:RadTemplatedPicker.PopupSettings>
    </telerik:RadTemplatedPicker>
    

    Define the SelectorTemplate

    <ControlTemplate x:Key="SelectorTemplate">
      <Grid ColumnDefinitions="*, *"
            HeightRequest="250">
          <Grid.Style>
              <OnPlatform x:TypeArguments="Style">
                  <On Platform="WinUI">
                      <Style TargetType="Grid">
                          <Setter Property="WidthRequest" Value="{Binding Width, Source={x:Reference picker}}" />
                      </Style>
                  </On>
              </OnPlatform>
          </Grid.Style>
          <telerik:RadSpinner x:Name="countriesSpinner"
                              Grid.Column="0"
                              ItemsSource="{Binding Countries}"
                              DisplayMemberPath="Name" />
          <telerik:RadSpinner x:Name="citiesSpinner"
                              Grid.Column="1"
                              ItemsSource="{Binding SelectedItem.Cities, Source={x:Reference countriesSpinner}}"
                              SelectedItem="{TemplateBinding SelectedValue}"
                              DisplayMemberPath="Name" />
      </Grid>
    </ControlTemplate>
    

    Define the HeaderTemplate

    <ControlTemplate x:Key="HeaderTemplate">
      <Grid BackgroundColor="DarkGray">
          <Grid.ColumnDefinitions>
              <ColumnDefinition />
              <ColumnDefinition />
          </Grid.ColumnDefinitions>
          <Label Text="Origin Country"
                 HorizontalOptions="Center"
                 VerticalOptions="Center"
                 TextColor="White" />
          <Label Grid.Column="1"
                 Text="Origin City" 
                 HorizontalOptions="Center"
                 VerticalOptions="Center"
                 TextColor="White" />
      </Grid>
    </ControlTemplate>
    
  2. Add the following data item for the first spinner:

    public class Country : NotifyPropertyChangedBase
    {
    private string name;
    
    public Country()
    {
        this.Cities = new ObservableCollection<City>();
    }
    
    public string Name
    {
        get
        {
            return this.name;
        }
        set
        {
            if (value != this.name)
            {
                this.UpdateValue(ref this.name, value);
            }
        }
    }
    
    public ObservableCollection<City> Cities { get; }
    }
    
  3. Add the following data item for the second spinner:

    public class City : NotifyPropertyChangedBase
    {
    private string name;
    
    public string Name
    {
        get
        {
            return this.name;
        }
        set
        {
            if (value != this.name)
            {
                this.UpdateValue(ref this.name, value);
            }
        }
    }
    }
    
  4. Define a sample ViewModel:

    public class LocationViewModel : NotifyPropertyChangedBase
    {
    private Country fromCountry;
    private City fromCity;
    
    public LocationViewModel()
    {
        this.Countries = new ObservableCollection<Country>
        {
            new Country
            {
                Name = "Austria",
                Cities =
                {
                    new City { Name = "Graz" },
                    new City { Name = "Innsbruck" },
                    new City { Name = "Linz" },
                    new City { Name = "Ratz" },
                    new City { Name = "Salzburg" },
                    new City { Name = "Vienna" },
                    new City { Name = "Wolfsberg" },
                    new City { Name = "Zeltweg" }
                }
            },
            new Country
            {
                Name = "Belgium",
                Cities =
                {
                    new City { Name = "Antwerp" },
                    new City { Name = "Assesse" },
                    new City { Name = "Bruges" },
                    new City { Name = "Charleroi" },
                    new City { Name = "Lint" },
                    new City { Name = "Ranst" },
                    new City { Name = "Schaffen" },
                    new City { Name = "Veurne" },
                    new City { Name = "Zingem" },
                }
            },
            new Country
            {
                Name = "Denmark",
                Cities =
                {
                    new City { Name = "Aalborg" },
                    new City { Name = "Aarhus" },
                    new City { Name = "Billund" },
                    new City { Name = "Copenhagen" },
                    new City { Name = "Karup" },
                    new City { Name = "Odense" },
                    new City { Name = "Viborg" },
                    new City { Name = "Vojens" }
                }
            },
            new Country
            {
                Name = "France",
                Cities =
                {
                    new City { Name = "Aurillac" },
                    new City { Name = "Belley" },
                    new City { Name = "Carcassonne" },
                    new City { Name = "Caen" },
                    new City { Name = "Deauville" },
                    new City { Name = "La Rochelle" },
                    new City { Name = "Nice" },
                    new City { Name = "Marseille" },
                    new City { Name = "Paris" },
                    new City { Name = "Rodez" }
                }
            },
            new Country
            {
                Name = "Germany",
                Cities =
                {
                    new City { Name = "Baden-Baden" },
                    new City { Name = "Berlin" },
                    new City { Name = "Borkum" },
                    new City{ Name = "Bremen" },
                    new City{ Name = "Dortmund" },
                    new City{ Name = "Dresden" },
                    new City{ Name = "Hamburg" },
                    new City{ Name = "Hannover" },
                    new City{ Name = "Leipzig" },
                    new City{ Name = "Mannheim" },
                    new City{ Name = "Munich" },
                    new City{ Name = "Nuremberg" }
                }
            },
            new Country
            {
                Name = "Italy",
                Cities =
                {
                    new City { Name = "Aosta" },
                    new City { Name = "Bari" },
                    new City { Name = "Bologna" },
                    new City { Name = "Parma" },
                    new City { Name = "Rimini" },
                    new City { Name = "Rome" }
                }
            },
            new Country
            {
                Name = "Netherlands",
                Cities =
                {
                    new City { Name = "Amsterdam" },
                    new City { Name = "Bonaire" },
                    new City { Name = "Eindhoven" },
                    new City { Name = "Maastricht" },
                    new City { Name = "Rotterdam" }
                }
            },
            new Country
            {
                Name = "Portugal",
                Cities =
                {
                    new City { Name = "Braga" },
                    new City { Name = "Cascais" },
                    new City { Name = "Lisbon" },
                    new City { Name = "Porto" }
                }
            },
            new Country
            {
                Name = "Spain",
                Cities =
                {
                    new City { Name = "Alicante" },
                    new City { Name = "Barcelona" },
                    new City { Name = "Madrid" },
                    new City { Name = "Seville" },
                    new City { Name = "Valencia" },
                    new City { Name = "Zaragoza" }
                }
            },
            new Country
            {
                Name = "United Kingdom",
                Cities =
                {
                    new City { Name = "Bristol" },
                    new City { Name = "Liverpool" },
                    new City { Name = "London" },
                    new City { Name = "Manchester" },
                    new City { Name = "Norwich" },
                    new City { Name = "Southampton" }
                }
            },
        };
    }
    
    public Country FromCountry
    {
        get
        {
            return this.fromCountry;
        }
        set
        {
            if (value != this.fromCountry)
            {
                this.UpdateValue(ref this.fromCountry, value);
            }
        }
    }
    
    public City FromCity
    {
        get
        {
            return this.fromCity;
        }
        set
        {
            if (value != this.fromCity)
            {
                this.UpdateValue(ref this.fromCity, value);
            }
        }
    }
    
    public ObservableCollection<Country> Countries { get; }
    }
    
  5. Set the defined LocationViewModel as a BindingContext of the page:

    this.BindingContext = new LocationViewModel();
    
  6. In addition to this, you need to add the following namespace:

    xmlns:telerik="http://schemas.telerik.com/2022/xaml/maui"
    

The following image shows the TemplatedPicker visual structure:

TemplatedPicker

See Also

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