I'm building Xamarin.Forms application.
My View:
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="TestApp.Mobile.Views.MainView">
<Grid>
<Frame x:Name="TheFrame" />
</Grid>
</ContentPage>
Then In App.cs I want to access TheFrame. Like this:
MainView mainWindow = new MainView ();
someFunction(mainWindow.TheFrame);
But! This is how auto-generated MainView.cs looks like:
public partial class MainView : ContentPage {
private Frame MainFrame;
private void InitializeComponent() {
this.LoadFromXaml(typeof(MainView));
MainFrame = this.FindByName<Frame>("MainFrame");
}
}
WHY?! How can I access TheFrame in App.cs?
You would only be able to access the Frame from the code-behind using the x:Name property. Why do you need to access it from App.cs?
You could declare the Frame in App.cs and then add it to your page, which would allow it to be accessed from anywhere.
Related
I'm using the AnimationNavigationPage nuget package (found here) to try and create a page slide animation going from right to left. So far it seems that all I'm able to get is left to right and it doesn't reflect when I change the animation type / subtype.
I'm sure I'm just missing something small but for the life of me I can't see it.
MainPage.xaml.cs
using FormsControls.Base;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
namespace PageNavigationExample
{
// Learn more about making custom code visible in the Xamarin.Forms previewer
// by visiting https://aka.ms/xamarinforms-previewer
[DesignTimeVisible(false)]
public partial class MainPage : AnimationPage
{
public MainPage()
{
InitializeComponent();
}
private async void Button_Clicked(object sender, EventArgs e)
{
await Navigation.PushAsync(new Page1());
}
}
}
MainPage.xaml
<?xml version="1.0" encoding="utf-8" ?>
<controls:AnimationPage
xmlns:controls="clr-namespace:FormsControls.Base;assembly=FormsControls.Base" xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
x:Class="PageNavigationExample.MainPage">
<controls:AnimationPage.PageAnimation>
<controls:SlidePageAnimation Duration="Short" Type="Slide" Subtype="FromRight"/>
</controls:AnimationPage.PageAnimation>
<StackLayout>
<!-- Place new controls here -->
<Label Text="Main page"
HorizontalOptions="Center"
VerticalOptions="CenterAndExpand" />
<Button Text="Main page button"
Clicked="Button_Clicked"/>
</StackLayout>
</controls:AnimationPage>
And then just basic content pages for navigation purposes that I haven't modified...Page1, Page2, etc.
What am I missing here to just get the slide animation to slide in from the right when I click a button and slide in from the left when I click the Back button?
And then just basic content pages for navigation purposes that I
haven't modified...Page1, Page2, etc.
Have you let your Page1, Page2, etc to inherit AnimationPage and set the PageAnimation?
for example:
app.xaml.cs :
public App()
{
InitializeComponent();
MainPage = new AnimationNavigationPage(new MainPage());
}
MainPage.xaml.cs:
public partial class MainPage : AnimationPage
{
public MainPage()
{
InitializeComponent();
}
private async void Button_Clicked(object sender, EventArgs e)
{
await Navigation.PushAsync(new Page1());
}
}
MainPage.xaml:
<?xml version="1.0" encoding="utf-8" ?>
<controls:AnimationPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
xmlns:controls="clr-namespace:FormsControls.Base;assembly=FormsControls.Base"
x:Class="App18.MainPage">
<controls:AnimationPage.PageAnimation>
<controls:SlidePageAnimation Duration="Medium" Subtype="FromRight" />
</controls:AnimationPage.PageAnimation>
<StackLayout>
<!-- Place new controls here -->
<Label Text="Main page"
HorizontalOptions="Center"
VerticalOptions="CenterAndExpand" />
<Button Text="Main page button"
Clicked="Button_Clicked"/>
</StackLayout>
</controls:AnimationPage>
Page1.xaml.cs:
public partial class Page1: AnimationPage
{
public Anim2()
{
InitializeComponent();
}
}
Page1.xaml:
<?xml version="1.0" encoding="utf-8" ?>
<controls:AnimationPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
xmlns:controls="clr-namespace:FormsControls.Base;assembly=FormsControls.Base"
x:Class="App18.Page1">
<controls:AnimationPage.PageAnimation>
<controls:SlidePageAnimation Duration="Short" Type="Slide" Subtype="FromRight"/>
</controls:AnimationPage.PageAnimation>
<StackLayout>
<Label Text="Welcome to Xamarin.Forms!"
VerticalOptions="CenterAndExpand"
HorizontalOptions="CenterAndExpand" />
</StackLayout>
</controls:AnimationPage>
the effect like:
I ask this question with reference to this website https://developer.xamarin.com/guides/xamarin-forms/user-interface/images/#Local_Images
I tried the xaml code on the website and it works, however after I created a new xamarin PCL project and tested the c# code. It failed to display images.
What I did:
Removed everything from the AboutPage.xaml till 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"
x:Class="EmbbedImages.Views.AboutPage"
xmlns:vm="clr-namespace:EmbbedImages.ViewModels;"
Title="{Binding Title}">
<ContentPage.BindingContext>
<vm:AboutViewModel />
</ContentPage.BindingContext>
</ContentPage>
And then for the AboutPage.xaml.cs, I modified it such that it looks like the following:
using Xamarin.Forms;
namespace EmbbedImages.Views
{
public partial class AboutPage : ContentPage
{
public AboutPage()
{
InitializeComponent();
var beachImage = new Image { Aspect = Aspect.AspectFit };
beachImage.Source = ImageSource.FromFile("butterfly.jfif");
}
}
}
I have ensured that the butterfly.jfif image is added into my android drawable folder, however no images are being displayed. As I am new to xamarin and Android and c# any help would be greatly appreciated.
The image probably won't display, because it's not part of the Page.
If you've added it to the Page and it still won't show it would have to be a problem in loading / opening the file / decoding it.
Either you add it in XAML or edit your code to the following:
using Xamarin.Forms;
namespace EmbbedImages.Views
{
public partial class AboutPage : ContentPage
{
public AboutPage()
{
InitializeComponent();
var beachImage = new Image { Aspect = Aspect.AspectFit };
beachImage.Source = ImageSource.FromFile("butterfly.jfif");
this.Content = beachImage;
}
}
}
Adding it in XAML would look like that:
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="EmbbedImages.Views.AboutPage"
xmlns:vm="clr-namespace:EmbbedImages.ViewModels;"
Title="{Binding Title}">
<ContentPage.BindingContext>
<vm:AboutViewModel />
</ContentPage.BindingContext>
<ContentPage.Content>
<Image x:Name="beachImage" Aspect="AspectFit">
</ContentPage.Content>
</ContentPage>
And the code behind:
using Xamarin.Forms;
namespace EmbbedImages.Views
{
public partial class AboutPage : ContentPage
{
public AboutPage()
{
InitializeComponent();
beachImage.Source = ImageSource.FromFile("butterfly.jfif");
}
}
}
I have a problem when trying to load the Icon of a ToolbarItem in Xamarin: It doesn't show up. The toolbar certainly exists. I have handled the Click method and it works, but the Icon is not visible. the ".ico" file exists in all the "drawable" folders in the Android project. It's the same .ico file I use in another solution and there it works just fine as the icon of a ToolbarItem, but here it doesn't work. I have tried to load an embedded image, but it doesn't work either. If I set its Text property, it is shown properly. I have a HomePage which is a MasterDetailPage, and the detail of this page is RootPage. On RootPage I have the ToolbarItem. Here are my xaml codes and the code behind:
HomePage:
<?xml version="1.0" encoding="utf-8" ?>
<MasterDetailPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:views="clr-namespace:ITEC.Views;assembly=ITEC"
x:Class="ITEC.Views.HomePage"
IsPresented="True">
<MasterDetailPage.Master>
<ContentPage Title="Home" Padding="0,20,0,0">
<StackLayout>
<ListView x:Name="listView">
<ListView.ItemTemplate>
<DataTemplate>
<TextCell Text="{Binding Title}"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</ContentPage>
</MasterDetailPage.Master>
<MasterDetailPage.Detail>
<views:RootPage/>
</MasterDetailPage.Detail>
</MasterDetailPage>
Code behind:
using ITEC.Services;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace ITEC.Views
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class HomePage : MasterDetailPage
{
private OptionService _optionService;
public HomePage()
{
InitializeComponent();
Detail=new NavigationPage(new RootPage());
_optionService = new OptionService();
listView.ItemsSource = _optionService.GetOptions();
}
}
}
RootPage:
<?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:embedded="clr-namespace:ITEC.MarkupExtensions"
x:Class="ITEC.Views.RootPage">
<ContentPage.ToolbarItems>
<ToolbarItem Icon="settings.ico" Clicked="MenuItem_OnClicked"></ToolbarItem>
</ContentPage.ToolbarItems>
<StackLayout>
<Label>Hello world</Label>
</StackLayout>
</ContentPage>
Code behind:
using System;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;
namespace ITEC.Views
{
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class RootPage : ContentPage
{
public RootPage()
{
InitializeComponent();
}
private void MenuItem_OnClicked(object sender, EventArgs e)
{
DisplayAlert("Hello", "OK", "No");
}
}
}
Try png file for your icon. i think it might be work.
I want to develop a simple project with Xamarin.Form and MVVM. In my solution (named XamarinPOC) i have (in addition to standard Xamarin.Forms projects) one separate project for the model (XamarinPOC.Model) and one separate project for the ViewModel (XamarinPOC.ViewModel).
I defined in a XamarinPOC.ViewModel project an abstract class for a BaseViewModel class (that implements the INotifyPropertyChanged Interface) and after I've created a SummaryViewModel class that extend BaseViewModel class with a simple property:
namespace XamarinPOC.ViewModel
{
public class SummaryViewModel : BaseViewModel
{
private string _test = "The binding is OK!";
public String test
{
get
{
return _test;
}
set
{
_test = value;
OnPropertyChanged("test");
}
}
public SummaryViewModel(){}
}
}
Next I created a simple ContentPage (SummatyView) in a XamarinPOC project that contain only a label that i want show the text defined in ViewModel. I want to use a XAML for defining the View and the binding but when I run the app nothing is displayed, I no errors on compile-time and runtime but the text are not displayed. My XAML is 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:XamarinPOC.ViewModel,assembly=XamarinPOC.ViewModel"
x:Class="XamarinPOC.Summary"
Title="Summary List"
BindingContext="XamarinPOC.ViewModel.SummaryViewModel">
<StackLayout>
<Label Text="{Binding test}"/>
</StackLayout>
</ContentPage>
and finally my app.cs is:
namespace XamarinPOC
{
public class App : Application
{
public App()
{
MainPage = new Summary();
}
}
}
In the XamarinPOC project I've added a reference to XamarinPOC.ViewModel and XamarinPOC.Model assemblies.
I think the problem is in the XAML definition of binding, but i don't find the error. Where am I wrong?
To bind the view to the viewmodel from Xaml in your case do it like this
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:viewModels="clr-namespace:XamarinPOC.ViewModel; assembly=XamarinPOC.ViewModel"
x:Class="XamarinPOC.Summary"
Title="Summary List">
<ContentPage.BindingContext>
<viewModels:SummaryViewModel/>
</ContentPage.BindingContext>
<StackLayout>
<Label Text="{Binding test}"/>
</StackLayout>
</ContentPage>
One side note I noticed is with naming conventions, it is better to put all your ViewModels, even if it is only one viewModel, inside a folder named "ViewModels" So the namespace in your case would be XamarinPOC.ViewModels
Im trying to add some items to a Listview which i added using Xamarin.Forms markup in an xaml file.
The button can be accessed by hooking with the click event.But since the listview is empty i need the event like ondraw like in winforms, so that i can hook to it when it is drawn.
In the XAML file I have :
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="ButtonXaml.ButtonXamlPage">
<StackLayout>
<Button Text="Tap for click count!"
BorderWidth="10"
TextColor="Red"
HorizontalOptions="Center"
Clicked="OnButtonClicked" />
<ListView
HorizontalOptions="Center"
/>
</StackLayout>
</ContentPage>
In the .cs file i have
using System;
using Xamarin.Forms;
namespace ButtonXaml
{
public partial class ButtonXamlPage
{
int count = 0;
public ButtonXamlPage()
{
InitializeComponent();
}
public void OnButtonClicked(object sender, EventArgs args)
{
((Button)sender).Text = "You clicked me";
}
}
}
So should i hook to events in Listview or can i do something like Resource.getElementbyID like we do in android
To access a Forms control in the code-behind, you need to assign it a name, using the x:Name attribute
in XAML:
<ListView HorizontalOptions="Center" x:Name="MyList" />
in code:
MyList.ItemsSource = myData;
There is a bug in Xamarin where VS doesn't see the defined x:Name
http://forums.xamarin.com/discussion/25409/problem-with-xaml-x-name-and-access-from-code-behind
Say you've defined an image in XAML:
<Image x:Name="myImageXName" />
Then this should work in code behind:
this.FindByName<Image>("myImageXName");
In my case the problem was lack of line XamlCompilation(XamlCompilationOptions.Compile)] in .xaml.cs file.
Example:
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
BindingContext = new MainPageViewModel();
}
...
}