I'm trying to get the result of variable into a textblock.text proprety, I'm using
this code:
bool isavailable = NetworkInterface.GetIsNetworkAvailable();
result = isavailable.ToString();
<TextBlock Height="62" HorizontalAlignment="Left" Margin="12,60,0,0"
Name="textBlock1" Text="{Binding result}" VerticalAlignment="Top"
Width="400" Foreground="White" TextWrapping="Wrap" />`
Do you need to keep the binding? The simplest approach here would be to simply use:
textBlock1.Text = result;
However, the better approach would be to use a ViewModel implementing INotifyPropertyChanged with an appropriate property. Then you would make your TextBlock bind to the property, and set the property from your code. The property would raise the appropriate event, and the UI would update accordingly.
Related
I have this code and somehow I want to get the text value of the first label to the tapped event in the CS code. As the tapped event is on the grid I had an idea of putting the text value into x:Name.
<ViewCell >
<Grid VerticalOptions="CenterAndExpand" x:Name="{Binding [0].Name}" Tapped="atiSelectValueX" >
<local:StyledLabel Text="{Binding [0].Name}" HorizontalOptions="StartAndExpand" />
<local:StyledLabel IsVisible="{Binding [0].IsSelected}" TextColor="Gray" HorizontalOptions="End" Text="x" />
</Grid>
</ViewCell>
The CS code I have so far:
void atiSelectValueX(object sender, EventArgs e)
{
var cell = sender as Grid;
if (cell == null)
return;
var selected = cell. <<< I want to get the name here
What I would like to do is to get the x:Name value in the CS code. I was hoping to get the sender information but it seems like I cannot enter
cell.Name
Is there another way I can get a parameter like the name (which is the same as the text in the first label always) in the C# code?
The x:Name is metadata used by the XAML tools, not an actual property of the object. You could also bind Name to an unused property, like StyleID, and access that instead
<Grid VerticalOptions="CenterAndExpand" StyleId="{Binding [0].Name}" ...
and then
var selected = cell.StyleId;
I have a books list displayed in my long list selector like this
<DataTemplate x:Key="BooksItemTemplate">
<StackPanel Grid.Column="1" Grid.Row="0" VerticalAlignment="Top">
<TextBlock Name="booktitle" Text="{Binding BookTitle,Mode=OneWay}" Style="{StaticResource PhoneTextNormalStyle}" TextWrapping="Wrap" FontFamily="{StaticResource PhoneFontFamilySemiBold}"/>
<TextBlock Text="{Binding AuthorName,Mode=OneWay}" Style="{StaticResource PhoneTextNormalStyle}" TextWrapping="Wrap" FontFamily="{StaticResource PhoneFontFamilySemiLight}"/>
<Button Content="Add To Favourites" Tag="{Binding BookId,Mode=OneWay}" Click="Button_Click_1" ></Button>
</StackPanel>
</Grid>
</DataTemplate>
<phone:LongListSelector x:Name="bookslist" Grid.Row="1"
ListFooter="{Binding}"
ItemsSource="{Binding BooksList}"
Background="Transparent"
IsGroupingEnabled="False"
ListFooterTemplate ="{StaticResource booksListFooter}"
ItemTemplate="{StaticResource BooksItemTemplate}"/>
so there is an add to favourites button beside every book in the list . pressing that button i am entering the pressed book's id in my isolatedstoragesetting like this
private void Button_Click_1(object sender, RoutedEventArgs e)
{
Button bt = (Button)sender;
IsolatedStorageSettings settings = IsolatedStorageSettings.ApplicationSettings;
List<long> ListFavourites;
if (settings.Contains("ListFavourites"))
{
ListFavourites = settings["ListFavourites"] as List<long>;
}
else
{
ListFavourites = new List<long>();
}
if(!ListFavourites.Contains(Convert.ToInt64(bt.Tag)))
{
ListFavourites.Add(Convert.ToInt64(bt.Tag));
}
settings["ListFavourites"] = ListFavourites;
settings.Save();
}
problem:
now when loading the above book list(longlistselector) when the page loads i want to show or hide the add to favorites button based on whether the bookid is present in the isolatedstoragesetting or not. what i have tried here is that i have tried to bind the converter to the add to favourite button and also bind the convertparameter with bookid. but the convertparameter doesn't support binding.
so what is the technique i can use to show or hide the add to favourite button based on the book id presence in the favourite list in the isolatedstoragesetting?
how can i hide the button based when clicking it based on the bookid?
You are almost there in thinking to use a converter. The actual idea, when materialized, should look something like this.
First, you will need to implement a converter, in this case, you will need to convert the bookid to a Visibility value.
public class BookIdToVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, string language)
{
//value is booking id here, which means that you just need to check against the isolatedStorageSettings
return Visibility.Collapsed;
}
public object ConvertBack(object value, Type targetType, object parameter, string language)
{
return null;
}
}
In your DataTemplate, the binding should take place like this:
<Button Content="Add To Favourites" Tag="{Binding BookId,Mode=OneWay}"
Click="Button_Click_1" Visibility={Binding BookId,Converter={StaticResource TheConverterCreatedAbove}} >
</Button>
That should do the trick.
The MVVM way would be to expand your ViewModel. It would be much better to add an AddToFavoritesCommand to BookViewModel instead of putting the logic in code behind. If the button is bound to that Command it would automatically go disabled when the Command would properly (with CanExecuteChanged) switch CanExecute to false.
In your case, you can add a property IsFavourite or CanAddToFavoirtes and then use a standard BoolToVisibility converter (the Command execution would set this property and the BookViewModel would be initialized with the correct value read from IsolatedStorage).
All logic behind the presentation of Book and functionalities related to Book belong to BookViewModel.
I want to use a WriteableBitmap to render a programmatically instantiated UserControl to a jpg/png image to use it as a live tile background image in a Windows Phone 7.1 project, but DataBinding is not working as expected when rendering the control.
In general, the UserControl is something like this:
<UserControl>
<Grid x:Name="LayoutRoot" Height="173" Width="173" >
<Grid.Background >
<SolidColorBrush Color="{StaticResource PhoneAccentColor}" />
</Grid.Background >
<Grid.RowDefinitions>
<RowDefinition Height="27"/>
<RowDefinition Height="146"/>
</Grid.RowDefinitions >
<ItemsControl Grid.Row="1" Margin="10,0,0,0" ItemsSource="{Binding}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<StackPanel />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding MyBindingProperty, FallbackValue=xxx}" />
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
<TextBlock Text="Hello World" FontSize="22" Margin="5,0,0,0"/>
<TextBlock TextWrapping="Wrap" Text="{Binding Count, FallbackValue=-1}" FontSize="18.667" Margin="123,0,0,0"/>
</Grid>
</UserControl>
When I now put this control onto a PhoneApplicationPage and assign a list with items of my data structure to the DataContext property of the UserControl, everything works fine and I see one TextBlock for each list item and the Text property of that TextBlock is correctly displaying the value of the property of my data structure. Also the last TextBlock on the Grid displays correctly the current count of list items.
BUT when I'm now trying to programmatically create that UserControl, assign the same list to the DataContext and then use a WriteableBitmap to render it to an image file, it seems that all DataBindings within the DataTemplate of the ItemsControl aren't working anymore, they're displaying the FallbackValue now. Although the DataBinding of the outer TextBlock in the Grid is still working perfectly and also I got the correct number of TextBlocks in the StackPanel (= items in the bound list).
Here is my code for creating the the WriteableBitmap:
var tile = new MyTileControl { DataContext = this._myList };
tile.Arrange(new Rect(0, 0, 173, 173));
tile.Measure(new Size(173, 173));
var bmp = new WriteableBitmap(173, 173);
bmp.Render(tile, null);
bmp.Invalidate();
What's the problem with the DataBindings in the DataTemplate when rendering through a WriteableBitmap and how can I solve it?
I think, that your control not fully created yet, and you can't grab bitmap just after creation. Try to use Dispatcher.BeginInvoke or something else for delayed grabbing of image.
Also, add this control to your page and look where is a problem - in control creation or in bitmap? This give you more information about a problem.
I can't seem to get this to work right. Basically, I have an ObservableCollection that is bound to a list. Inside this collection, I have an object that I need to use to pass as a variable to a Command when it's executed. My plan was to pass this as CommandParameter, but I can't get it to work. The object is actually an Enum value, but I can't get it to work with anything but static text. Below is the code, it's using a MVVM concept using Interactivity(wi)and blend's dll(sl). The property is public on the ListItem, and does implement INotifyPropertyChanged.
Thanks.
<ListBox ItemsSource="{Binding Path=MyList}" ScrollViewer.VerticalScrollBarVisibility="Disabled">
<wi:Interaction.Triggers>
<wi:EventTrigger EventName="SelectionChanged">
<sl:InvokeDataCommand CommandParameter="{Binding MyList.ListItem.Property}" Command="{Binding Source={StaticResource Locator}, Path=MyTestPage.TestExecute}" />
</wi:EventTrigger>
</wi:Interaction.Triggers>
...
<ListBox x:Name="listBox" ItemsSource="{Binding Path=MyList}" ScrollViewer.VerticalScrollBarVisibility="Disabled">
<wi:Interaction.Triggers>
<wi:EventTrigger EventName="SelectionChanged">
<sl:InvokeDataCommand CommandParameter="{Binding ElementName=listBox, Path=SelectedItem.Property}" Command="{Binding Source={StaticResource Locator}, Path=MyTestPage.TestExecute}" />
</wi:EventTrigger>
</wi:Interaction.Triggers>
How about doing this? You want to bind to the selectedItem, not ?
MyList is your ObservableCollection ?
I'm having an issue when I try to pass the selectedIndex of my list from my "List" screen.
On my List screen I have the following binding:
Code Behind:
lbPrograms.ItemsSource = App.ViewModel.Items;
XAML:
<ListBox x:Name="lbPrograms" ItemsSource="{Binding Items}" SelectionChanged="lbPrograms_SelectionChanged">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel x:Name="DataTemplateStackPanel" Orientation="Horizontal">
<Image x:Name="ItemImage" Source="/images/ArrowImg.png" Height="43" Width="43" VerticalAlignment="Top" Margin="10,0,20,0"/>
<StackPanel>
<TextBlock x:Name="ItemText" Text="{Binding programName}" Margin="-2,-13,0,0" Style="{StaticResource PhoneTextExtraLargeStyle}"/>
<TextBlock x:Name="DetailsText" Text="{Binding createDate}" Margin="0,-6,0,3" Style="{StaticResource PhoneTextSubtleStyle}"/>
<TextBlock x:Name="programId" Text="{Binding programId}" Margin="0,-6,0,3" Style="{StaticResource PhoneTextSubtleStyle}"/>
</StackPanel>
<!--<Image x:Name="ItemFavs" Source="/images/favs.png" Height="43" Width="43" VerticalAlignment="Top" Margin="10,0,20,0"/>
<Image x:Name="ItemDelete" Source="/images/delete.png" Height="43" Width="43" VerticalAlignment="Top" Margin="10,0,20,0"/>-->
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
In my detail screen I look up using the selectedIndex value:
App.ViewModel.Refresh();
DataContext = App.ViewModel.Items[index].nValDictionary;
However, since I can't figure out how to just update a value in my iEnumerable collection I have been removingAt[index] and then re-adding to the collection.
So can anyone tell me, how do use update an existing element in my collection? If not, can I pass the programId (that is in my binding) instead of the selectedIndex as the indexes are getting all messed up after the Delete/Add functionality.
Please Advise.
UPDATE:
After speaking in several forums I should clear up that I am implement INotifyChanged Event on my properties in my object.
Basically the following snippet of code is my current issue:
private void FavBtn_Click(object sender, EventArgs e)
{
foreach (var item in App.ViewModel.Items)
{
if ((item.currentProgram == true) && (item.programId != index))
{
item.currentProgram = false;
}
if (item.programId == index)
{
item.currentProgram = true;
}
}
When I run this everything looks to be ok.
However, when I navigate to another page, I re-load the object and the changes are lost. It is almost like I need to save them before navigating, however, if I do a item.Save(); I get duplicates in my list.
I'm guessing you haven't implemented INotifyPropertyChanged on your Items class yet.
Implementing this will allow updates made in these objects to be updated through your data bindings.
Here's a walkthrough on how to implement INotifyPropertyChanged.
How to: Implement the INotifyPropertyChanged Interface
Is App.ViewModel.Items of type ObservableCollection<T>?
If so, when you modify a property of one of the collection items and raise a property change event (via INotifyPropertyChanged) indicating the collection property that your ListBox.ItemsSource is bound to, the DataTemplate bindings will do the rest.