refering to this Question Error when trying to explore my files and Folder of my Drive. But I am getting error that Selected directory get return null. Could you please help me.
I want to have a Back Button. I tried this Code:
private DelegateCommand _goBackCommand;
public DelegateCommand GoBackCommand =>
_goBackCommand ?? (_goBackCommand = new DelegateCommand(ExecuteGoBackCommand));
void ExecuteGoBackCommand()
{
_selectedDirectory.InputFilePath = Path.GetFullPath(Path.Combine(SelectedDirectory.InputFilePath, ".."));
ListDirectoryContent(_selectedDirectory);
ListDrives();
}
Xmal:
<Button x:Name="BackButton" Command="{Binding GoBackCommand}" Content="Back" Grid.Column="1" Grid.Row="0" Background="Pink" FontSize="10">
Related
My Xamarin Forms 5 app will allow users to upload their own images which can be large. I noticed that large images were taking a long time to show so I installed FFImageLoading and followed the instructions on their Github page at https://github.com/luberda-molinet/FFImageLoading/wiki/Xamarin.Forms-API.
Specifically, I installed the following packages:
Xamarin.FFImageLoading Version="2.4.11.982"
Xamarin.FFImageLoading.Forms Version="2.4.11.982"
Xamarin.FFImageLoading.Svg.Forms Version="2.4.11.982"
Xamarin.FFImageLoading.Transformations Version="2.4.11.982"
I also initialized it as follows:
Under Android, in OnCreate method of MainActivity.cs, I added FFImageLoading.Forms.Platform.CachedImageRenderer.Init(enableFastRenderer:true); AND FFImageLoading.Forms.Platform.CachedImageRenderer.InitImageViewHandler();
Under iOS, in FinishedLaunching() method of AppDelegate.cs, I added FFImageLoading.Forms.Platform.CachedImageRenderer.Init(); AND FFImageLoading.Forms.Platform.CachedImageRenderer.InitImageSourceHandler();
I first tried it without changing anything in my XAML files, meaning I used the regular Image control and images would NOT show at all.
I then tried the following and I see NOTHING at all:
...
xmlns:ffil="clr-namespace:FFImageLoading.Forms;assembly=FFImageLoading.Forms"
...
<ffil:CachedImage
Source="{Binding FileUrl}"
DownsampleWidth="150"
DownsampleToViewSize="True"/>
IMPORTANT:
I also want to mention that the images are displayed within CollectionView controls AND in all cases, their source is a URL and NOT a local path.
Any idea what maybe the issue here and how to fix it?
As I'm aware FFImageLoading is not maintained anymore. A lot of apps are still using the package but keep in mind that reported open issues will most likely not be fixed. It is sad because this is one of the most popular packages for Xamarin Forms, but it looks like we will have to start looking for alternatives.
Good luck with this.
I checked your steps that you followed the instructions.Obviously,your steps are correct and I manage to display the image{using URL} with CollectionView as you said,hope it can give you some insights.
Model:
MyModel.cs
public class MyModel
{
public int id { get; set; }
public string FileUrl { get; set; }
}
View:
MainPage.xaml
<CollectionView ItemsSource="{Binding MyModels}">
<CollectionView.ItemsLayout>
<GridItemsLayout Orientation="Vertical" Span="2" />
</CollectionView.ItemsLayout>
<CollectionView.ItemTemplate>
<DataTemplate>
<ContentView Padding="0">
<ffil:CachedImage
Source="{Binding FileUrl}"
DownsampleWidth="150"
DownsampleToViewSize="True"/>
</ContentView>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
Bind the ViewModel in backend:
BindingContext = new MainPageViewModel();
ViewModel:
MainPageViewModel.cs
public class MainPageViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private ObservableCollection<MyModel> myModels;
public ObservableCollection<MyModel> MyModels
{
get { return myModels; }
set { myModels = value; }
}
public MainPageViewModel()
{
MyModels = new ObservableCollection<MyModel>
{
new MyModel{id = 1, FileUrl = "http://loremflickr.com/600/600/nature?filename=simple.jpg"},
new MyModel{id = 2, FileUrl ="http://loremflickr.com/600/600/nature?filename=simple.jpg"},
new MyModel{id = 3, FileUrl = "http://loremflickr.com/600/600/nature?filename=simple.jpg"},
new MyModel{id = 4, FileUrl ="http://loremflickr.com/600/600/nature?filename=simple.jpg"},
new MyModel{id = 5, FileUrl = "http://loremflickr.com/600/600/nature?filename=simple.jpg"},
new MyModel{id = 6, FileUrl ="http://loremflickr.com/600/600/nature?filename=simple.jpg"}
};
}
}
Update:
In Android, it works well.However,in iOS there's already a reported issue:
github.com/luberda-molinet/FFImageLoading/issues/1498
In my view I have:
<ContentView.BindingContext>
<vm:HomeViewModel />
</ContentView.BindingContext>
In that viewmodel I have:
public void test(object sender, EventArgs e)
{
var x = 0;
}
That's just for testing so I can hit a breakpoint, but I can't seem to Bind the function to the View:
<StackLayout BackgroundColor="White">
<StackLayout.GestureRecognizers>
<TapGestureRecognizer Command="{Binding test }" />
</StackLayout.GestureRecognizers>
I've tried to hook it up with Tapped property as well, adding parentheses, I keep getting:
Severity Code Description Project File Line Suppression State
Error Position 57:51. No method OnTapGestureRecognizerTapped with correct signature found on type
I know I'm missing something here, can anyone shed some light on my problem?
You need a command in your viewmodel binding to:
public ICommand cmdTest { get { return new Command(() => test())
Now in your view you are able to bind to cmdTest:
<TapGestureRecognizer Command="{Binding cmdTest}" />
I have the following Xamarin Forms page that throws an exception on this line...
The first time this page is loaded, the OnAppearing works fine, sets the focus properly, and doesn't throw an exception.
When I navigate back to this page (ie, logout), OnAppearing is throwing the following...
System.ObjectDisposedException: Cannot access a disposed object.
Object name: 'Xamarin.Forms.Platform.Android.EntryRenderer'.
What is the best way to set focus to a control on a page in Xamarin Forms?
I'm not sure what is in your XAML, but if you define the x:Name="_entry" on the Entry in XAML, and use that name to access the control directly instead of FindByName, it should work fine.
I try to reproduce your issue at my side, but it works fine and there is no issue when I click Button to navigate another page and coming back. Please take a look my code:
<StackLayout>
<Label
HorizontalOptions="CenterAndExpand"
Text="Welcome to Xamarin.Forms!"
VerticalOptions="CenterAndExpand" />
<Entry
x:Name="UserNameentry"
HorizontalOptions="FillAndExpand"
VerticalOptions="CenterAndExpand" />
<Button
x:Name="btn1"
Clicked="btn1_Clicked"
HeightRequest="50"
HorizontalOptions="FillAndExpand"
Text="btn1"
VerticalOptions="CenterAndExpand"
WidthRequest="200" />
</StackLayout>
public Page4()
{
InitializeComponent();
}
protected override void OnAppearing()
{
base.OnAppearing();
var usernameentry = FindByName("UserNameentry") as Entry;
usernameentry.Focus();
}
private async void btn1_Clicked(object sender, EventArgs e)
{
Page3 page = new Page3();
await Navigation.PushModalAsync(page);
}
If you still have this issue, please provide some code about xaml here.
first of all sorry for my english.
I am developing a WP7 app, and I still haven't completely understood the data binding structure. I have a page that has some data obtained through data binding. Data is generated within the .cs, and it works fine.
But on another page I have some data that is obtained from data binding too, but I want it to come from a UI input text instead. It's simple, just a textbox and a textblock, so the user writes something on the textbox and so it shows up on the textblock that's on the same page. But it's not working, the textblock remains empty.
It's something like this:
<TextBox Name="TestInput">
<TextBlock Text="{Binding TestText}">
Above is what's on the XAML.
public partial class NewItem : PhoneApplicationPage
{
public String TestText { get; set; }
public NewItem()
{
InitializeComponent();
TestText = "TestInput.Text";
}
}
And this above is what's on the C#.
BUT!! It doesn't end here. Since the textblock wasn't showing anything, I ended desperately trying to assign some plain String to the TestText property. Like this:
TestText = "HELLO WORLD";
But when the app starts and the page loads, the textblock shows nothing. I just don't understand what am I missing, or doing wrong.
I will appreciate if someone could clear me up the databinding structure, or at least explain me what did I do wrong so I can figure it out myself.
Thanks in advance guys!
You have to assign the DataContext before you want the binding effect.So whenever there is a change in the text box, you write the code in the textchanged event.
this.DataContext=TestText
And one more change that you need to perform is that you are not actually setting the property.It should be like
TestText=TestInput.Text
for your understanding of binding i am putting a simple working example..just follow this..
this is you page on which you bind the data of textbox to someproperty textboxText..when you finished writing in this textbox.then all the writtentext automatically come ino this property. and this property is also binded to textbloack so when your textbloack got focus it will got to the get of the property and automatically fill it.
<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
<StackPanel Orientation="Horizontal" >
<TextBox x:Name="testTextbox" Height="50" Width="200" Text="{Binding TextboxText,Mode=TwoWay}" />
<TextBlock x:Name="testTextblock" Height="50" Width="1000" Text="{Binding TextboxText,Mode=OneWay}" Foreground="White" />
</StackPanel>
</Grid>
this is your page.cs class in which i have also shown you how to implement inotifyproperty changed..it will help you in future..
public sealed partial class MainPage : Page,INotifyPropertyChanged
{
public MainPage()
{
this.InitializeComponent();
this.DataContext = this;
}
private string _TextboxText;
public string TextboxText
{
get
{
return _TextboxText;
}
set
{
_TextboxText = value;
FirePropertyChanged("TextboxText");
testTextblock.UpdateLayout();
}
}
protected override void OnNavigatedTo(NavigationEventArgs e)
{
}
public event PropertyChangedEventHandler PropertyChanged;
protected void FirePropertyChanged(string propertyName)
{
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
I was trying to use the MVVM pattern on my first (very simple) WP7 app but I got seriously stuck and now I am just trying to get it working without caring about MVVM.
I have a MainViewModel for my MainPage, which works fine. I have a button that passes some data and navigates to a "details page." I had setup a navigation service to navigate to the details page and pass parameters, which works fine. I just couldn't get the databinding to the view working. Since it is a simple app, I decided I would pass the data from the DetailsPageVieModel.cs to the DetailsPage.xaml.cs code behind and do the work there. Here is what that veiw model portion looks like.
public override void Initialize(IDictionary<string, string> parameters)
{
DetailsPage dp = new DetailsPage();
//DetailsPage dp = Application.Current.RootVisual as DetailsPage;
base.Initialize(parameters);
parameters.TryGetValue("url", out vidUrl);
dp.LoadVideoData(vidUrl);
}
In my DetailsPage.xaml.cs I have the following:
public void LoadVideoData(string url)
{
HtmlWeb doc = new HtmlWeb();
doc.LoadAsync("http://mydomain.com/video.php?url=" + url);
doc.LoadCompleted += doc_LoadCompleted;
}
private void doc_LoadCompleted(object sender, HtmlDocumentLoadCompleted e)
{
this.vidTitle.Text = e.Document.GetElementbyId("title").InnerText;
vidId = e.Document.GetElementbyId("youtubeId").InnerText;
this.vidUrl.Source = new Uri("http://mydomain.com/video.php?url=" + vidUrl, UriKind.Absolute);
BitmapImage bi = new BitmapImage();
using (IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication())
{
using (IsolatedStorageFileStream fileStream = myIsolatedStorage.OpenFile("temp.jpg", FileMode.Open, FileAccess.Read))
{
bi.SetSource(fileStream);
this.vidImg.Height = bi.PixelHeight;
this.vidImg.Width = bi.PixelWidth;
}
}
this.vidImg.Source = bi;
}
And here is the relevant DetailsPage.xaml code
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<StackPanel>
<TextBlock x:Name="vidTitle" Canvas.ZIndex="99" />
<TextBlock Canvas.ZIndex="99" Text="Tap on the image to view the video." FontSize="14" Margin="0"/>
<Button Margin="0 -50" Padding="0" BorderThickness="0">
<Image x:Name="vidImg" Height="225" />
</Button>
<StackPanel Canvas.ZIndex="99" Height="516">
<phone:WebBrowser x:Name="vidUrl" IsScriptEnabled="True" Height="516" Margin="0"/>
</StackPanel>
</StackPanel>
</Grid>
I am guessing the problem lies with the following
DetailsPage dp = new DetailsPage();
//DetailsPage dp = Application.Current.RootVisual as DetailsPage;
Neither of these lines of code works. The first line executes properly but the page doesn't get updated with the proper data. And the second line gives me a runtime error message when it gets to the dp.LoadVideoData(vidUrl); line.
This is my first Windows Phone app and I would appreciate any help anyone can provide.
Kamal
After digging around some more, I found the following solution.
DetailsPage currentPage = (App.Current as App).RootFrame.Content as DetailsPage;
I put this code in DetailsPageViewModel.cs. But for other newbies like me, there is nothing special about the name of the file. It could have very well been Monkey.cs. The above code just gives you access to the code behind of the current page being displayed.