I am trying to read a text file that I have included with the project folder itself in a separate folder. I am trying to read this text file and then add each line to a list, each line as a separate item in the list, then I am looking to bind it to a listbox and each listbox item (each line previously) would be a hyperlink in the listbox. It's been very frustrating since the app just freezes every single time as soon as the code starts executing at runtime. What could be the problem?
I tried searching here a lot. I tried several of the similar problems' solutions but no use.
Code:
public partial class Page2 : PhoneApplicationPage
{
public Page2()
{
InitializeComponent();
// Will contain the names of malls added through a text file
List<string> Mall_List = new List<string>();
using(StreamReader reader = new StreamReader("/Mall_List/Mall_List.txt"))
{
while(reader.Peek() >= 0)
{
Mall_List.Add(reader.ReadLine());
}
reader.Close();
}
Malllist.ItemsSource = Mall_List;
}
}
XAML:
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<ListBox Height="426" HorizontalAlignment="Left" Margin="6,6,0,0" Name="Malllist" VerticalAlignment="Top" Width="444">
<ListBox.ItemTemplate>
<DataTemplate>
<HyperlinkButton Name="MallNameLinkButton"
Content="{Binding}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Grid>
Instead of just reading from "local file",
using(StreamReader reader = new StreamReader("/Mall_List/Mall_List.txt"))
you should know WP7 has Isolated Storage, for every app.
Please make sure you are familiar with it by reading following article:
http://www.windowsphonegeek.com/tips/all-about-wp7-isolated-storage--intro-to-isolated-storage
More precisely, reading files is described in following article:
http://www.windowsphonegeek.com/tips/all-about-wp7-isolated-storage-read-and-save-text-files
Related
Say I have a simple ItemTemplate for a ListView
<ListView ItemsSource="{x:Bind ListItems}">
<ListView.ItemTemplate>
<DataTemplate x:DataType="local:TextItem">
<TextBlock Text="{x:Bind Item}"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
MainPage.xaml
When I run the app, I get a ListView populated with TextBlocks - one for each item in ListItems (which is a behind defined variable). However, in the XAML designer, I see nothing.
So, is there a way to preview the ItemTemplate/DataTemplate in the XAML designer, with a set number of placeholder TextBlocks with placeholder text replacing the Text="{x:Bind Item}"? Or just preview a single TextBlock?
This is not a duplicate of
Design View of a DataTemplate in a ResourceDictionary in Visual Studio - because I can't use Blend. Everything I've looked up that says use Blend in a certain way merely gives me the message 'This feature is not available for projects targeting "Windows 10 Fall Creators Update (10.0; Build 16299)"'
Can I preview my DataTemplate(s) in my collection-based controls in the designer? - well, perhaps it is, but I don't understand the accepted answer, which is now several years old. An answer containing an example tailored to my question would be really helpful.
Microsoft actually posted a (semi helpful) tutorial on this in April of this year: link
Requirements
Whatever you want to display, you will need this at the top of your XAML code (should be there by default if you created the page using VS's templates):
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
A simple list of strings
For something simple like a list of strings, something like this will work just fine (taken from the above mentioned MSDN page):
<ListView>
<d:ListView.Items>
<system:String>Item One</system:String>
<system:String>Item Two</system:String>
<system:String>Item Three</system:String>
</d:ListView.Items>
</ListView>
Display something more complex
If you want to use a data source from somewhere else in your code, it gets a little more ugly:
First you need to set your data context (usually done at the page level, but you can also add it just on the element where you want to use it):
d:DataContext="{d:DesignInstance
yournamespace:YourDataSourceClass,
IsDesignTimeCreatable=True}"
And on the ListView add:
d:ItemsSource="{Binding data}"
If you are using an ItemTemplate, you will need to add "d:" variants for everything you want to pull from your data source.
Full example code:
XAML:
<Page
x:Class="exampleApp.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:exampleApp"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
d:DataContext="{d:DesignInstance local:DesignTimeData,
IsDesignTimeCreatable=True}"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid>
<Grid>
<ListView ItemsSource="{x:Bind ListItems}" d:ItemsSource="{Binding DummyData}">
<ListView.ItemTemplate>
<DataTemplate x:DataType="local:TextItem">
<TextBlock Text="{x:Bind Item}" d:Text="{Binding Item}"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</Grid>
</Grid>
</Page>
C#:
using System.Collections.ObjectModel;
using Windows.UI.Xaml.Controls;
namespace exampleApp {
public sealed partial class MainPage : Page {
public ObservableCollection<TextItem> ListItems;
public MainPage() {
this.InitializeComponent();
//populate you ListItems list
}
}
public class TextItem {
public string Item { get; set; }
}
public class DesignTimeData {
public ObservableCollection<TextItem> DummyData { get; set; } = new ObservableCollection<TextItem> {
new TextItem { Item = "foo" },
new TextItem { Item = "bar" },
new TextItem { Item = "bla" },
new TextItem { Item = "blubb" }
};
}
}
Remarks
It seems you have to use "Binding" rather than "x:Bind" for the design-time bindings. From what I understand, x:Bind works using code generated at compile time, which is not executed by the XAML designer
When you change your Binding declarations or data source code, you will have to recompile to see the changes in the designer. Other design changes will reflect in real time
Binding is more limited than x:Bind in some regards (notably you cannot bind to class methods using Binding, only x:Bind). Keep that in mind when writing your design-time data
Sadly some of the more convenient ways of getting design-time data into your app are WPF and Xamarin only (Blends' data window, data declared in XAML file, and especially auto-generated sample data)
(Everything was tested using Visual Studio 2019 version 16.10.3.)
I'm trying to save a file to the device.
The problem is that I'm hardcoding the filename from code behind.
My requirement is to ask the user to save a file with a user defined filename. How can I ask the user to save a file by opening a filesave dialog in Xamarin.Forms?
Have you solved it? Can you post your solution in case?
This question could fit your requirements, it uses this plugin: Xam.plugin.filepicker Xam.Plugin.FilePicker Works fine but can't get file
Here is the easiest popup page using Rg.Plugins.Popup
cs:
public partial class PromptPopup : PopupPage
{
public event EventHandler Oked;
public event EventHandler Canceled;
public PromptPopup(string title, string text)
{
InitializeComponent();
PopupText.Text = text;
PopupTitle.Text = title;
}
private void OnCancel(object sender, EventArgs e)
{
this.Canceled(sender, e);
PopupNavigation.PopAsync(false);
}
private void OnOk(object sender, EventArgs e)
{
this.Oked(sender, e);
PopupNavigation.PopAsync(false);
}
}
its xaml:
<StackLayout VerticalOptions="Center" HorizontalOptions="FillAndExpand" Padding="20, 20, 20, 20">
<StackLayout BackgroundColor="White" Padding="10, 10, 10, 10">
<Label x:Name="PopupTitle" Text="PromptPopupTitle" TextColor="Gray" FontSize="20" HorizontalOptions="Center" />
<ScrollView>
<StackLayout>
<StackLayout Orientation="Horizontal">
<Label x:Name="PopupText"
HorizontalOptions="FillAndExpand"
HorizontalTextAlignment="Center"
TextColor="Gray"></Label>
</StackLayout>
<StackLayout Orientation="Horizontal" HorizontalOptions="FillAndExpand">
<Button Text="{i18n:Translate PopupButtonCancel}" Clicked="OnCancel" HorizontalOptions="FillAndExpand"></Button>
<Button Text="{i18n:Translate PopupButtonOk}" Clicked="OnOk" HorizontalOptions="FillAndExpand"></Button>
</StackLayout>
</StackLayout>
</ScrollView>
</StackLayout>
(this page comes from a PopupPage instead of ContentPage)
and you can call it like this
var page = new PromptPopup("title", "text");
page.Oked += Page_OkedLogout;
page.Canceled += Page_CanceledLogout;
await PopupNavigation.PushAsync(page);
further deep support: https://github.com/rotorgames/Rg.Plugins.Popup
You have to implement the file picker yourself, there's no built in way to do that, best to go out to GitHub and look around if that's what you're after.
It sounds to me like you could easily achieve what you're after by just popping a text box, having a user enter a file name, validate the filename with a regex or something and then just saving the file with that file name, you could even just save the file and give them the option to rename the file by listing them all out, but that's all too broad for me to give you an exact implementation, so the best I can do for you is tell you the simple way to do what you're wanting to do.
After selecting file you just open Popup with "Entry" and save file using Entry Text. you can open popup using "Rg.Plugins.Popup"
Does anyone know how to make a listbox with multiple images. I want to be able to capture an image and then display on the screen, then capture another and display after the first one and so on. It is basically images gallery page that I want to create. I would like to store them somewhere on the phone, so they can be retrieved when the application runs again.
So it should be something like in the picture: http://blog.xamarin.com/wp-content/uploads/2012/02/wp2.png
Thank you in advance, I have been doing researches about it but can't find anything.
Well, that is fairly easy. You use a ListBox set the ItemsPanel to a WrapPanel, and either bind ItemsSource to a ObservableCollection (or List/Array, but ObservableCollection is better suited for Bindings).
There are multible ways to do it
Lets take the easiest approach. In xaml you define your ListBox:
<ListBox x:Name="listbox">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<toolkit:WrapPanel />
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Margin="5"
Background="{StaticResource PhoneChromeBrush}"
Height="180"
Width="180">
<Image Source="{Binding}" />
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
In your code behind, you can load the images with something like this:
ObservableCollection<BitmapImage> images = new ObservableCollection<BitmapImage>();
List<String> bitmapuris = ....
using (IsolatedStorageFile isoStore = IsolatedStorageFile.GetUserStoreForApplication())
{
foreach(var bitmapuri in bitmapuris)
{
System.Windows.Media.Imaging.BitmapImage bitmap = new System.Windows.Media.Imaging.BitmapImage();
if (isoStore.FileExists(bitmapuri))
{
using (IsolatedStorageFileStream stream = isoStore.OpenFile(bitmapuri, System.IO.FileMode.Open, System.IO.FileAccess.Read))
{
bitmap.CreateOptions = System.Windows.Media.Imaging.BitmapCreateOptions.BackgroundCreation;
bitmap.SetSource(stream);
}
}
images.Add(bitmap);
}
}
listbox.ItemsSource = images;
With bitmapuris being a List with all of your saved images urls.
Thats basicly what I'm using in some of my apps (though I use ViewModels and Bindings and don't set ItemsSource manually)
Hope this helps
edit:
On how to capture and save images you can read this article:
http://www.c-sharpcorner.com/UploadFile/mahakgupta/capture-save-and-edit-image-in-windows-phone-7/
I would save the Images in a specific folder i.e. "/Images/". That way you can load all images you previously captured on you app start with the code I posted above with List<String> bitmapuris set with this method:
List<String> getFiles(String folderpath)
{
IsolatedStorageFile storage = IsolatedStorageFile.GetUserStoreForApplication();
return storage.GetFileNames(folderpath).ToList();
}
like this List<String> bitmapuris = getFiles("/Images/*");
and when you captured an image you can simple add your image to your ListBox this way:
System.Windows.Media.Imaging.BitmapImage bitmap = new System.Windows.Media.Imaging.BitmapImage();
bitmap.CreateOptions = System.Windows.Media.Imaging.BitmapCreateOptions.BackgroundCreation;
bitmap.SetSource(myimagestream);
images.Add(bitmap);
providing images is the ObservableCollection<BitmapImage> you set as an ItemsSource to your ListBox.
This is now almost your fully working app, when compined with the link from above.
I'm developing a Windows Phone 7 app, and I have two xaml pages. From the first one, I embed two app bar links to select an image from gallery or capture an image using the camera. I would like the image chosen on the first page to be displayed on a second page, with the app bar buttons showing a confirm yes or no. As of now, I have an image control on the first page (barcodeImage) that gets updated with the choice.
MainPage.xaml
<controls:PanoramaItem Header="welcome">
<ScrollViewer Name="sv1" VerticalScrollBarVisibility="Auto">
<StackPanel Height="1100">
<TextBlock TextWrapping="Wrap">Random text here.
</TextBlock>
<Grid x:Name="Grid2" Grid.Row="1" Margin="12,0,12,0">
<Image Height="150" Margin="28,30,168,0" Name="barcodeImage" Stretch="Fill" VerticalAlignment="Top" d:LayoutOverrides="VerticalAlignment" />
</Grid>
</StackPanel>
</ScrollViewer>
</controls:PanoramaItem>
MainPage.xaml.cs
void cameraCaptureTask_Completed(object sender, PhotoResult e)
{
if (e.TaskResult == TaskResult.OK)
{
BitmapImage bmp = new BitmapImage();
bmp.SetSource(e.ChosenPhoto);
barcodeImage.Source = bmp;
}
}
Confirm.xaml
<!--ContentPanel - place additional content here-->
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<Image Margin="64,36,57,100" x:Name="barcodeImageFinal" Stretch="Fill" />
</Grid>
I'd like barcodeImageFinal to display the final bitmap. How can I make this work? Thanks for looking :)
As I understand your question, you want to create a bitmap in a member of MainPage and then access it from Confirm. One approach would be to create a public static property of some class for your bitmap. For example, maybe create public static BitmapImage FinalBitmap in your App. Then you could set the value of the property in your cameraCaptureTask_Completed and then create a Loaded handler in your Confirm class that sets image source to the stored bitmap.
I think the answer to your question title is yes if you make the member static, although the other class isn't really "external". A normal class member won't be accessible because you don't have an instance of that class.
This has to be simple, at least it was in good old .Net where it took maybe four lines of code. I'm working in VS2010, C#, WPF4.
I have a user control with a textbox. When I click a button in the main window, I want my user control textbox to reflect some text. Is this possible in WPF4 with less than 500 lines of esoteric code?
The problem is that while I know the textbox is getting the new text as evidenced from breakpoints in the user control code, that text is never being reflected to the main window. The main window still shows the original text. It has to be some kind of binding thing, and I really don't think I should have to create templates and resources and all for this simple situation. It's got to be something simple that I'm forgetting in the forest of WPF4. Below is what I have. After clicking the button, the textbox is still blank; it does not say "hello earthlings."
In the user control code:
public partial class UserControl1 : UserControl
{
public static readonly DependencyProperty TextProperty;
public UserControl1()
{
InitializeComponent();
}
static UserControl1()
{
TextProperty = DependencyProperty.Register("Text", typeof(string), typeof(UserControl1), new UIPropertyMetadata(null));
}
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
}
User control xaml:
<UserControl x:Class="WTFUserControlLibrary.UserControl1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006">
<Grid Height="164" Width="220">
<TextBox Name="txtTest" BorderBrush="red" BorderThickness="2" Height="25" Text="{Binding ElementName=UserControl1, Path=Text, Mode=TwoWay}"></TextBox>
</Grid>
(I have no idea what the text binding is supposed to be doing in this case.)
Main window code:
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void button1_Click(object sender, RoutedEventArgs e)
{
WTFUserControlLibrary.UserControl1 uc = new WTFUserControlLibrary.UserControl1();
uc.Text = "hello earthlings";
}
}
and the main window xaml:
<Window x:Class="WpfApplication2.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:my="clr-namespace:WTFUserControlLibrary;assembly=WTFUserControlLibrary"
Title="MainWindow" Height="350" Width="525">
<Grid>
<Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="71,65,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" />
<my:UserControl1 HorizontalAlignment="Left" Margin="71,94,0,0" Name="userControl11" VerticalAlignment="Top" Height="116" Width="244" />
</Grid>
Thanks Earthlings (and also those who designed this mess!)
In your method button1_Click you are creating a new user control. This is not the usercontrol in the window and is never displayed.
Instead, give your usercontrol a name in the XAML:
x:Name="uc"
Then in the button1_Click method you just remove that first line where you create a new usercontrol.
update
You want the user control XAML to look more like this:
<UserControl x:Class="WTFUserControlLibrary.UserControl1"
x:Name="thisControl"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006">
<Grid Height="164" Width="220">
<TextBox Name="txtTest" BorderBrush="red"
BorderThickness="2" Height="25"
Text="{Binding ElementName=thisControl, Path=Text, Mode=TwoWay}" />
</Grid>
I added x:Name="thisControl" to the root UserControl element, and then referenced this in the binding.
I'll try to explain the binding:
You have this textbox inside your user control, but you want to be able to bind the text value to something outside the user control. What you've done is set up a dependency property on the user control, and bound that textbox to it, so you are using the binding infrastructure pass values from the top level of the UserControl to constituent controls inside it.
Basically, it looks like this:
data
---> bind UserControl1.Text to data
---> bind TextBox.Text to UserControl1.Text