I created a Prism Unity App (from the prism extension pack - really nice), added 2 new views and set up basic navigation between the views. This all worked fine without any hiccups.
What I really want is to use DryIoc (company policy). So I proceeded to remove the unity packages (Unity and Prism.Unity.Forms) and installed the DryIoc Packages (DryIoc and Prism.DryIoc.Forms). Fixed the App.xaml to use the correct namespace (xmlns:prism="clr-namespace:Prism.DryIoc;assembly=Prism.DryIoc.Forms") and alos fixed all the other references to use DryIoc and not the Unity References.
This all compiles and runs without any exceptions. But when I debug it is clear that the AutoWireup does not work as expected (at least as I expect it to). The breakpoint in the ViewModel's constructor (or any other place) is not hit and the Title bindings does not pull through.
Is there a Configuration/Setup or reference that I am missing?
My Code:
App.xaml:
<?xml version="1.0" encoding="utf-8" ?><prism:PrismApplication xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:prism="clr-namespace:Prism.DryIoc;assembly=Prism.DryIoc.Forms"
x:Class="XamFormsPrism.App"></prism:PrismApplication>
App.xaml.cs:
public partial class App : Prism.DryIoc.PrismApplication
{
public App(IPlatformInitializer initializer = null) : base(initializer) { }
protected override void ConfigureContainer()
{
base.ConfigureContainer();
}
protected override void OnInitialized()
{
this.InitializeComponent();
this.NavigationService.NavigateAsync(NavigationLinks.MainPage);
}
protected override void RegisterTypes()
{
this.Container.RegisterTypeForNavigation<MainPage>();
this.Container.RegisterTypeForNavigation<ViewA>();
this.Container.RegisterTypeForNavigation<ViewB>();
}
}
MainPage.xaml:
<?xml version="1.0" encoding="utf-8" ?><ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:prism="clr-namespace:Prism.Mvvm;assembly=Prism.Forms"
prism:ViewModelLocator.AutowireViewModel="True"
x:Class="XamFormsPrism.Views.MainPage"
Title="MainPage"><StackLayout HorizontalOptions="Center" VerticalOptions="Center">
<Label Text="{Binding Title}" />
<Button Text="{Binding NavigateText}" Command="{Binding NavigateCommand}" /> </StackLayout></ContentPage>
MainPageViewModel.cs:
public class MainPageViewModel : BindableBase, INavigationAware
{
private INavigationService navigationService = null;
private string _title = "Jose Cuervo";
public string Title
{
get { return _title; }
set { SetProperty(ref _title, value); }
}
public DelegateCommand NavigateCommand { get; private set; }
public MainPageViewModel(INavigationService navigationService)
{
this.navigationService = navigationService;
this.NavigateCommand = new DelegateCommand(this.navigate, this.canNavigate);
}
private void navigate()
{
this.navigationService.NavigateAsync("ViewA");
}
private bool canNavigate()
{
return true;
}
public void OnNavigatedFrom(NavigationParameters parameters)
{
}
public void OnNavigatedTo(NavigationParameters parameters)
{
if (parameters.ContainsKey("title"))
Title = (string)parameters["title"] + " and Prism";
}
}
As seen above I use the standard naming convention of PageName & PageNameViewModel with the AutoWireUp set to True.
This all worked fine with Unity but I am missing something in DryIoc...but what escapes me.
I have searched the entire project, there is no reference or trace left of Unity.
Any help is much appreciated.
I finally had time again to have a look at this. If I explicit register the ViewModels in the container everything works fine. So I am guessing that there is either a rule missing for the DryIoC container or when using DryIoC you have to explicitly register the ViewModels.
Related
I'm developing Multiplatform app through Xamarin.
I'm using custom entry in a separate view and I'm using in some pages of my app
This is my simple code for entry
<ContentView
xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="prova.MyView">
<ContentView.Content>
<Entry x:Name="MyEntry"
TextChanged="MyEntry_TextChanged"
Margin="100"/>
</ContentView.Content>
and cs file
public partial class MyView : ContentView
{
public MyView()
{
InitializeComponent();
}
void MyEntry_TextChanged(System.Object sender, Xamarin.Forms.TextChangedEventArgs e)
{
}
}
in my pages I insert entry with this simple code
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="prova.MainPage"
xmlns:pages="clr-namespace:prova">
<StackLayout>
<pages:MyView/>
</StackLayout>
I wonder how can I get when MyEntry_TextChanged is fired in my ContentPage?
one solution is to use MessaggingCenter but I wonder if there's a better and more elegant solution
There are two ways I can think of to do this.
1. Inherit from the Entry class as Jason commented.
public class MyView : Entry
{
public MyView()
{
InitializeComponent();
}
}
This will expose the bindable TextChanged property which you can reference in XAML like you want to do.
2. Create the binding yourself
You can create the binding to a custom "TextChanged" property yourself, but this is more complicated and may achieve the same result with extra effort. You will also need to create a bindable "Text" property. The code below is untested, but uses the bindings I found in the Xamarin.Forms InputView class (which is what Entry derives from). This will be along the lines of what you need to do if you do not do it the way of #1. Exposing bindable properties to XAML will look like this:
public class MyView : ContentView
{
public MyView()
{
InitializeComponent();
}
public string Text
{
get
{
return (string)GetValue(TextProperty);
}
set
{
SetValue(TextProperty, value);
}
}
public static readonly BindableProperty TextProperty = BindableProperty.Create("Text", typeof(string), typeof(MyView), defaultValue: "", propertyChanged:
(bindable, oldValue, newValue) => ((MyView)bindable).OnTextChanged((string)oldValue, (string)newValue));
public event EventHandler<TextChangedEventArgs> TextChanged;
protected virtual void OnTextChanged(string oldValue, string newValue)
{
TextChanged?.Invoke(this, new TextChangedEventArgs(oldValue, newValue));
}
}
I hope my more comprehensive answer helps you choose the direction you want to go for this. If you want to learn more about Bindable Properties, check out Edward's link.
We have an app written with Pages and no pattern and I want to re-write it using MVVM. Currently we use a Picker for language selection and when the culture changes we set all label.Text controls again in order to redraw them in the new language.
I re-wrote the same page using MVVM and now SelectedItem in the Picker is bound to a Language object. In the setter for SelectedItem I also change the culture of my resx (AppResources.Culture) but the UI bound to it (e.g. Text="{x:Static resources:AppResources.Title) doesn't change language.
Full code in my SelectedItem setter:
SetProperty(ref selectedLanguage, value);
AppResources.Culture = value.Culture;
cultureManager.SetLocale(value.Culture);
How should I update all the Text of my UI? Is there any clean way to do something like this, it seems like a basic translation need... or it wasn't meant to be done, especially not without closing the view/app?
The approaches I found for localization using IMarkupExtension and this thread on Xamarin forums which in the end effectively re-creates the page...
My goal is to ideally reload text without having to re-create the view/close the app, using MVVM and clean code. I have about 10 views so it has to be something reusable.
Create you RESX Resources first. I use en, nl, fr for example.
Create the view model to binding the LocalizedResources.
public class ViewModelBase : INotifyPropertyChanged
{
public LocalizedResources Resources
{
get;
private set;
}
public ViewModelBase()
{
Resources = new LocalizedResources(typeof(LocalizationDemoResources), App.CurrentLanguage);
}
public void OnPropertyChanged([CallerMemberName]string property = null)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(property));
}
public event PropertyChangedEventHandler PropertyChanged;
}
In SettingsPage, use a picker to choose the language.
<StackLayout>
<Label Text="{Binding Resources[PickLng]}" />
<Picker ItemsSource="{Binding Languages}" SelectedItem="{Binding SelectedLanguage, Mode=TwoWay}" />
</StackLayout>
View model of SettingsPage.
public class SettingsViewModel : ViewModelBase
{
public List<string> Languages { get; set; } = new List<string>()
{
"EN",
"NL",
"FR"
};
private string _SelectedLanguage;
public string SelectedLanguage
{
get { return _SelectedLanguage; }
set
{
_SelectedLanguage = value;
SetLanguage();
}
}
public SettingsViewModel()
{
_SelectedLanguage = App.CurrentLanguage;
}
private void SetLanguage()
{
App.CurrentLanguage = SelectedLanguage;
MessagingCenter.Send<object, CultureChangedMessage>(this,
string.Empty, new CultureChangedMessage(SelectedLanguage));
}
}
Do not forget to binding the context.
I have upload on GitHub, you could download from DynamicallyBindingRESXResources folder on my GitHub for reference.
https://github.com/WendyZang/Test.git
I have Template1 that inherits from ContentView. For the purpose of this question I removed a lot of things in the template to make it simple.
<?xml version="1.0" encoding="UTF-8"?>
<ContentView xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:local="clr-namespace:Japanese;assembly=Japanese" x:Class="Japanese.Template1" x:Name="this">
<Label Grid.Column="0" Text="{Binding Text, Source={x:Reference this}}" />
</ContentView>
and the Template1 C# back end
namespace Japanese
{
public partial class Template1 : ContentView
{
public CardOrderTemplate()
{
InitializeComponent();
}
}
}
I would like this template to share bindings in this class and so I tried some different ways to do this but none seem to work. Here's what I was trying. Not sure but I guess I need something like a ViewModel for the template but I am not sure how I could go about implementing this.
namespace Japanese
{
public class SegBase : ContentView
{
public static readonly BindableProperty TextProperty = BindableProperty.Create(nameof(Text), typeof(string), typeof(SegTemplate), default(string));
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
}
}
Does anyone know how I can do this? I tried making the Template1 class inherit from SegBase but it gives me an error because the XAML is a type ContentView and the C# is not inheriting from ContentView.
I have a viewmodel that inherits from BindableBase and implements IApplicationLifecycle. However, IApplicationLifecycle.OnResume() and IApplicationLifecycle.OnSleep() is never called on neither iOS nor android.
How do you use IApplicationLifecycle? I cant seem to find any documentation for it. Thanks in advance!
In my App.xaml.cs i have:
NavigationService.NavigateAsync("NavigationPage/MainPage");
and my MainPage.xaml looks like this:
<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:PrismApp.Views;assembly=PrismApp"
xmlns:prism="clr-namespace:Prism.Mvvm;assembly=Prism.Forms"
prism:ViewModelLocator.AutowireViewModel="True"
x:Class="PrismApp.Views.MainPage"
Title="MainPage">
<TabbedPage.Children>
<local:APage Icon="tabicon_mapspage.png" />
<local:BPage Icon="tabicon_profilepage.png" />
<local:CPage Icon="tabicon_statuspage.png" />
</TabbedPage.Children>
Finally my MainPageViewModel looks like this:
public class MainPageViewModel : BindableBase, IApplicationLifecycle
{
private string _title;
public string Title
{
get { return _title; }
set { SetProperty(ref _title, value); }
}
public void OnResume()
{
var debug = 42;
}
public void OnSleep()
{
var debug = 42;
}
}
I have put a minimal project of it here: https://github.com/RandomStuffAndCode/PrismApp
Since you are in a TabbedPage the IApplicationAware methods are only being invoked on the TabbedPage.CurrentPage (SelectedTab), as that is the current active page.
By the way, you can change this behavior by overriding the OnResume and OnSleep methods in your app class to achieve your goal. Use the existing code as a guide: https://github.com/PrismLibrary/Prism/blob/master/Source/Xamarin/Prism.Forms/PrismApplicationBase.cs#L171
A bit confused here, I seem to have followed the steps that would allow me to make use of value converters.
I have my converter defined with a key, as such:
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage Title="Article"
xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:controls="clr-namespace:XamarinMobile.Controls;assembly=XamarinMobile"
xmlns:converters="clr-namespace:XamarinMobile.Converters;assembly=XamarinMobile"
x:Class="XamarinMobile.ArticlePage">
<ContentPage.Resources>
<ResourceDictionary>
<converters:FontSizeConverter x:Key="FontSizeMapper"></converters:FontSizeConverter>
</ResourceDictionary>
</ContentPage.Resources>
I then make use of my converter in my XAML, as such:
<ContentView Padding="10,-10,10,0" Grid.Row="2" Grid.Column="0">
<StackLayout>
<Label x:Name="LabelAuthor" FontSize="{Binding 20, Converter={StaticResource FontSizeMapper}, ConverterParameter=20}" />
<Label x:Name="LabelPublishDate" FontSize="{Binding 10, Converter={StaticResource FontSizeMapper}, ConverterParameter=10}"/>
</StackLayout>
</ContentView>
And here is my actual converter code:
namespace XamarinMobile.Converters
{
public class FontSizeConverter : Xamarin.Forms.IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if(value is double)
{
return App.NormalizeFontSize((double)value);
} else
{
return value;
}
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
}
I then put a break point in my value converter, but it never hits. Is there something obvious that I'm missing here? I'm pretty sure I followed the directions to a tee.
Your breakpoint isn't being hit due to what Gerald Versluis said. Your binding is broken. What your binding is saying is: Bind to the property named "10" on the BindingContext, and use the Converter FontSizeMapper, passing it an extra ConverterParameter of 10. "10" isn't a valid property name, so the binding is breaking. If you look in your logs, you should see a message similar to: "Binding: '10' property not found on ..."
One way to fix it would be to remove the "Path" you're trying to bind to and only make use of the ConverterParameter (assuming you don't need to bind to any real properties):
FontSize="{Binding Converter={StaticResource FontSizeMapper}, ConverterParameter=20}"
Note that you'll need to make use of the parameter in the converter, rather than the value (eg. if (parameter is double)).
If you don't need to bind to any properties, another way to fix it would be to use a custom markup extension instead.
[ContentProperty("FontSize")]
public class FontSizeMapperExtension : IMarkupExtension
{
public double FontSize { get; set; }
public object ProvideValue(IServiceProvider serviceProvider)
{
return App.NormalizeFontSize(FontSize);
}
}
Then you could use it in your XAML like:
FontSize="{converters:FontSizeMapper FontSize=10}
Edit
An example of binding to a property on an object:
public class YourViewModel
{
public double VMFontSize { get; set; }
}
public partial class ArticlePage : ContentPage
{
public ArticlePage()
{
InitializeComponent();
// NOTE: You'd probably get your view-model another way
var viewModel = new YourViewModel { VMFontSize = 10 };
BindingContext = viewModel;
}
}
Now that your view-model is set as the binding context, you can set the binding like:
FontSize="{Binding VMFontSize, Converter={StaticResource FontSizeMapper}}"
What this says is: Bind the FontSize property on the label to the VMFontSize property on the current BindingContext (your view-model), using the converter to map between the view-model's VMFontSize and the Label's FontSize. I left the ConverterParameter off here as it isn't really needed in this example, but you could pass one if you need it.
I would do this a different way, using a custom attached property, see more on attached properties here https://developer.xamarin.com/guides/xamarin-forms/xaml/attached-properties/
Here is a sample for your scenario, first we need to define an attached property, it can be in any class, I called mine FontHelper
namespace App23
{
public static class FontHelper
{
public static readonly BindableProperty FontSizeProperty =
BindableProperty.CreateAttached("FontSize", typeof(double), typeof(FontHelper), 0d, propertyChanging:OnPropertyChanging);
public static bool GetFontSize(BindableObject view)
{
return (bool)view.GetValue(FontSizeProperty);
}
public static void SetFontSize(BindableObject view, bool value)
{
view.SetValue(FontSizeProperty, value);
}
private static void OnPropertyChanging(BindableObject bindable, object oldValue, object newValue)
{
if (bindable is Label)
{
var label = bindable as Label;
double fontSize = (double)newValue;
// normalize your font size here
label.FontSize = fontSize;
}
}
}
}
Then to use it in XAML, it looks like this:
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:App23"
x:Class="App23.MainPage">
<Label Text="Welcome to Xamarin Forms!"
VerticalOptions="Center"
HorizontalOptions="Center" local:FontHelper.FontSize="50"/>
</ContentPage>