Develop Reference

Windows 8.1 App C# XAML help: Show message if no radio buttons are selected

I'm trying to code my ESurvey application. I have a list of radio buttons. Here is the code on SurveyPage1.xaml:
<StackPanel Grid.Row="1" Margin="-10,10,10,-10">
<TextBlock Text="PARLIAMENT VISITOR CENTRE SURVEY" FontWeight="Bold" FontSize="48" Margin="100,0,0,0" VerticalAlignment="Top"/>
<TextBlock Text="1. How would you describe your overall visit experience?" Margin="100,100,0,0" FontSize="18"/>
<RadioButton Name="radioExcellent" Content="Excellent" Margin="100,10,0,0" FontSize="12"/>
<RadioButton Name="radioGood" Content="Good" Margin="100,10,0,0" FontSize="12"/>
<RadioButton Name="radioAverage" Content="Average" Margin="100,10,0,0" FontSize="12"/>
<RadioButton Name="radioPoor" Content="Poor" Margin="100,10,0,0" FontSize="12"/>
</StackPanel>
<Button Name="nextButton1" Content="Next" HorizontalAlignment="Left" Margin="1250,525,0,0" Grid.Row="1" VerticalAlignment="Center" Background="#FFED2E38" Click="Button_S1_S2"/>
And my SurveyPage1.xaml.cs:
private void Button_S1_S2(object sender, RoutedEventArgs e)
{
if (this.Frame != null)
{
this.Frame.Navigate(typeof(SurveyPage2));
}
}
What I want to do is that if no radio button is checked, it will not proceed to the next page(clicking nextButton1 would show an error saying "Please enter an option.")
Can someone help me on this? Much appreciated!

You can just check the IsChecked property of all the RadioButtons in a nextButton1 click handler:
private async void Button_S1_S2(object sender, RoutedEventArgs e)
{
if (radioExcellent.IsChecked != true && radioGood.IsChecked != true && radioAverage.IsChecked != true && radioPoor.IsChecked != true)
{
MessageDialog md = new MessageDialog("Please rate the content before proceeding!");
await md.ShowAsync();
}
else
{
if (this.Frame != null)
{
this.Frame.Navigate(typeof(SurveyPage2));
}
}
}

In the click event handler for the next button, you check if some of the radiobuttons are set

How to use (if possible) same source a tap event uses in a ContextMenu button click?

Im tweaking a Sound Player app to try and include a Save as Ringtone function. App uses Tiles and a Viewmodel. Tapping each tile plays a sound. I added a Context Menu to the Data Template to give the option on a Tap and Hold event to save that sound as a Ringtone. I am having some issues figuring out just how to use the same source as the Tiles use to play the sound. Below, first code is portion of the Mainpage.xaml. Then the c# code. What I have set at the bottom of the MainPage.cs for the _customRingtone Source is wrong. The emulator stops at "SoundData data = selector.SelectedItem as SoundData;" I cant figure out how to do the source in a similar way the Tile taps get the audio for playing it. I didnt post the ViewModel but can if you want me to. That is where the Tile Groups and sounds are loaded.
<phone:PhoneApplicationPage.Resources>
<DataTemplate x:Key="SoundTileDataTemplate">
<StackPanel>
<toolkit:ContextMenuService.ContextMenu>
<toolkit:ContextMenu>
<toolkit:MenuItem Click="Save_Click" Header="Save as Ringtone" />
</toolkit:ContextMenu>
</toolkit:ContextMenuService.ContextMenu>
<Grid Background="{StaticResource PhoneAccentBrush}"
Margin="0, 0, 12, 12">
<Grid VerticalAlignment="Top"
HorizontalAlignment="Right"
Width="40"
Height="40"
Margin="0, 6, 6, 0">
<Ellipse Stroke="{StaticResource PhoneForegroundBrush}"
StrokeThickness="3" />
<Image Source="/Assets/AppBar/Play.png" />
</Grid>
<StackPanel VerticalAlignment="Bottom">
<TextBlock Text="{Binding Title}" Margin="6, 0, 0, 6" />
</StackPanel>
</Grid>
</StackPanel>
</DataTemplate>
</phone:PhoneApplicationPage.Resources>
<!--LayoutRoot is the root grid where all page content is placed-->
<Grid x:Name="LayoutRoot" Background="Transparent">
<MediaElement
Name="AudioPlayer"
Volume="1" />
<!--Pivot Control-->
<phone:Pivot Title="{Binding Path=LocalizedResources.ApplicationTitle,
Source={StaticResource LocalizedStrings}}">
<phone:PivotItem Header="{Binding Animals.Title}">
<phone:LongListSelector x:Name="Animal"
SelectionChanged="LongListSelector_SelectionChanged"
Margin="0,0,-12,0"
ItemsSource="{Binding Animals.Items}"
LayoutMode="Grid"
GridCellSize="150,150"
ItemTemplate="{StaticResource SoundTileDataTemplate}"
/>
</phone:PivotItem>
public partial class MainPage : PhoneApplicationPage
{
private readonly SaveRingtoneTask
_CustomRingtone;
// Constructor
public MainPage()
{
InitializeComponent();
// Set the data context of the listbox control to the sample data
DataContext = App.ViewModel;
_CustomRingtone = new SaveRingtoneTask();
_CustomRingtone.Completed +=
customeRingtone_Completed;
BuildLocalizedApplicationBar();
}
// Load data for the ViewModel Items
protected override void OnNavigatedTo(NavigationEventArgs e)
{
if (!App.ViewModel.IsDataLoaded)
{
App.ViewModel.LoadData();
}
}
private void LongListSelector_SelectionChanged(object sender,
SelectionChangedEventArgs e)
{
LongListSelector selector = sender as LongListSelector;
// verifying our sender is actually a LongListSelector
if (selector == null)
return;
SoundData data = selector.SelectedItem as SoundData;
// verifying our sender is actually SoundData
if (data == null)
return;
private void customeRingtone_Completed(object sender, TaskEventArgs e)
{
if (e.TaskResult == TaskResult.OK)
{
MessageBox.Show(#"Saved");
}
else if (e.TaskResult == TaskResult.Cancel)
{
MessageBox.Show(#"Canceled");
}
else
{
MessageBox.Show(#"Not Saved");
}
}
private void Save_Click(object sender, System.Windows.RoutedEventArgs e)
{
LongListSelector selector = sender as LongListSelector;
SoundData data = selector.SelectedItem as SoundData;
**_CustomRingtone.Source = new Uri(data.FilePath, UriKind.RelativeOrAbsolute**);
_CustomRingtone.DisplayName = "Ring";
_CustomRingtone.Show();
}

You Save_Click event handler is not passed a LLS, but a context MenuItem. The DataContext of the MenuItem is the object you are after.
private void Save_Click(object sender, System.Windows.RoutedEventArgs e)
{
var element = (FrameworkElement)sender;
SoundData data = element.DataContext as SoundData;
_CustomRingtone.Source = new Uri(data.FilePath, UriKind.RelativeOrAbsolute**);
_CustomRingtone.DisplayName = "Ring";
_CustomRingtone.Show();
}

Tap and hold Listbox Windows Phone

Does anybody know how can I add event whenever I press my listbox it will directly run my code. I need it to change my listbox selected item. This is my xaml:
<ListBox x:Name="ListNabi" SelectionChanged="ListNabi_SelectionChanged" ItemsSource="{Binding}" Tap="ListNabi_Tap" Hold="ListNabi_Hold">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Margin="5,0,5,0">
<!--<Image Source="{Binding ImageSource}" Stretch="None"/>-->
<Grid Width="480" Background="White">
<Image x:Name="listDaun" Source="/Images/Button/Button List.png"
Margin="0,5,5,5" Width="38" HorizontalAlignment="Left"></Image>
<TextBlock x:Name="namaNabi" TextWrapping="NoWrap"
Text="{Binding Name}" FontFamily="{StaticResource PhoneFontFamilyNormal}"
FontSize="36" Foreground="#00ADCE" Margin="40,5,0,5"></TextBlock>
<Rectangle Margin="0,50,0,0" Height="2" Fill="#00ADCE" Width="480"/>
</Grid>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
And in CS I did like this:
private void ListNabi_Hold(object sender, System.Windows.Input.GestureEventArgs e)
{
changeColor("#00ADCE", "#FFFFFF", "#FFFFFF", "/Images/Button/Button List1.png");
}
private void ListNabi_Tap(object sender, System.Windows.Input.GestureEventArgs e)
{
if (ListNabi.SelectedIndex != -1)
{
id = ListNabi.SelectedIndex;
}
MessageBox.Show("tes");
changeColor("#00ADCE", "#FFFFFF", "#FFFFFF", "/Images/Button/Button List1.png");
}
private void ListNabi_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (ListNabi.SelectedIndex != -1)
{
id = ListNabi.SelectedIndex;
changeColor("#00ADCE", "#FFFFFF", "#FFFFFF", "/Images/Button/Button List1.png");
NavigationService.Navigate(new Uri("/Pages/25_Nabi/DetailPage.xaml?id="
+ ListNabi.SelectedIndex, UriKind.Relative));
ListNabi.SelectedIndex = -1;
}
}
But it will only run my code (in this context changeColor()) whenever I hold my listbox after some time or after I release my finger. Is there any event I can use to start run my code whenever my finger start touch?

For that use the following events: ManipulationStarted, ManipulationDelta and ManipulationCompleted. You will get everything you need from positions to the number of different touch points.
You can do sophisticated things with it like dragging and pinching.

How to select an item from a listbox in windows phone?

I've a list of data,
Each row will show a data and will have a button, when i click the data shown i want give some data to the previous page and when i click the button in the same row i want to send that same data to next page.
My Xaml code,
<ListBox x:Name="List" HorizontalAlignment="Left" Height="612" Margin="6,7,0,0" VerticalAlignment="Top" Width="443" SelectionChanged="List_SelectionChanged_1">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" Width="420" Height="50">
<TextBlock x:Name="tbName" Width="400" Height="44" FontSize="22" FontWeight="Bold" Text="{Binding Name}" />
<Button x:Name="DetailButton" Height="44" Width="20" Content=">" FontWeight="Bold" Click="DetailButton_Click_1"/>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
and the code for List_SelectionChanged_1 event handler is,
private void List_SelectionChanged_1(object sender, SelectionChangedEventArgs e)
{
Display selectedItemData = (sender as ListBox).SelectedValue as Display;
NavigationService.Navigate("/Page1.xaml",selectedItemData);
}
and my DetailButton_Click_1 event handler is,
private void DetailButton_Click_1(object sender, RoutedEventArgs e)
{
Display selectedItemData = (sender as ListBox).SelectedValue as Display;
NavigationService.Navigate("/page3.xaml", selectedItemData);
}
Things work fine for *List_SelectionChanged_1*, but i get an exception while executing
Display selectedItemData = (sender as ListBox).SelectedValue as Display;
of the DetailButton_Click_1 , i get an exception a null exception,
An exception of type 'System.NullReferenceException' occurred in ExpenseApp.DLL but was not handled in user code
What should i do make it work?

The underlying problem is that the sender of the button click event is the button, not the ListBox.
Also note that clicking the button on your data template will not necessarily select that item in the list. Try to grab the clicked item's data context and use that instead of .SelectedItem
private void DetailButton_Click_1(object sender, RoutedEventArgs e)
{
var clickedUIElement = sender as Button;
if (null == clickedUIElement) { Return; }
Display selectedItemData = clickedUIElement.DataContext as Display;
if(null != selectedItemData)
{
NavigationService.Navigate("/page3.xaml", selectedItemData);
}
}
Your code, as it stands, will have a null reference since you can't cast a Button as a ListBox.

try verify if the selectvalue is null before execute the code:
private void DetailButton_Click_1(object sender, RoutedEventArgs e)
{
If ((sender as ListBox).SelectedValue != null){
Display selectedItemData = (sender as ListBox).SelectedValue as Display;
NavigationService.Navigate("/page3.xaml", selectedItemData);
}
}

How to extract value from selected TextBlock element in a ListBox?

I'm using a ListBox to display all values contained in Dictionary<> object:
<ListBox Height="519" x:Name="ContactsListBox" Width="460" Margin="0,0,0,0" SelectionChanged="ContactsListBox_SelectionChanged">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical">
<TextBlock Text="{Binding Key}" Margin="5" Foreground="{StaticResource PhoneAccentBrush}"/>
<TextBlock x:Name ="LastNameData" Text="{Binding Value}" Margin="20, 0" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Content is filled by the following code:
Dictionary<long, Contact> contacts = new Dictionary<long, Contact>();
this.ContactsListBox.ItemsSource = contacts;
Now, I would like to 'know' which specific "Contact" in ListBox is currently selected, either by knowing its Key, or just by extracting value from "LastNameData" TextBlock.
I tried doing something like that, but obviosly it doesn't work:
private void ContactsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ListBox lb = this.ContactsListBox.SelectedItem as ListBox;
this.Test_SomeOtherTextBlock.Text = lb.ToString();
}
I would really appreciate your help!

you can even do the follwing:
<ListBox Height="519" x:Name="ContactsListBox" Width="460" Margin="0,0,0,0" >
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical">
<TextBlock Text="{Binding Key}" Margin="5"/>
<TextBlock x:Name ="LastNameData" Text="{Binding Value}" Margin="20, 0" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<Grid DataContext="{Binding ElementName=ContactsListBox, Path=SelectedItem}" Margin="0,470,0,0">
<TextBlock Text="{Binding Value}"/>
</Grid>
So you don't need code behind...
BR,
TJ

There are several problems:
In Xaml you probably don't want to display the class name, but a reasonable string, for example:
<TextBlock x:Name ="LastNameData" Text="{Binding Value.LastName}" Margin="20, 0" />
In the selection processing the selected item is KeyValuePair<...>. You could easily find it yourself, if you looked at the returned type in debugger. (Should be kind of a reflex for a programmer, hence a questions like above should never appear :))
private void ContactsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e) {
KeyValuePair<long, Contact> kv = (KeyValuePair<long, Contact>)this.ContactsListBox.SelectedItem;
Contact c = (Contact)kv.Value;
Debug.WriteLine(c.LastName);
}

Your code is good, using ListBox.SelectedItem is the right approach.
I think the problem is that you should cast it as ListBoxItem, not ListBox. And also to get to its value using DataContext, so something like along these lines (not tested, I'm not sure about accessing DataContext value in the last line):
private void ContactsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ListBoxItem lbi = this.ContactsListBox.SelectedItem as ListBoxItem;
var dataContext = lbi.DataContext;
this.Test_SomeOtherTextBlock.Text = dataContext.Value.ToString();
}

Try this it works for me, will help you to...
private void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ListBox ContactListBox = sender as ListBox;
ListBoxItem listBoxItem = ContactListBox .ItemContainerGenerator.ContainerFromItem(ContactListBox.SelectedItem) as ListBoxItem;
if (listBoxItem == null)
{
return;
}
TextBlock txtBlock = FindVisualChildByName(listBoxItem, "ListTextBlock");
MessageBox.Show(txtBlock.Text);
}
private static T FindVisualChildByName<T>(DependencyObject parent, string name) where T : DependencyObject
{
for (int i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
{
var child = VisualTreeHelper.GetChild(parent, i);
string controlName = child.GetValue(NameProperty) as string;
if (controlName == name)
{
return child as T;
}
T result = FindVisualChildByName<T>(child, name);
if (result != null)
return result;
}
return null;
}

private void ContactsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ListBox lb = this.ContactsListBox.SelectedItem as ListBox;
this.Test_SomeOtherTextBlock.Text = lb.ToString();
}
will go something like this..
private void ContactsListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ListBox lb = this.ContactsListBox.SelectedItem as ListBox;
DataTemplate template=lb.ContentTemplate;
//Now here you have to extract the content of the data template
and then you need to extract the TextBlock from that content.
}
This is just an overview of the functionality.Sorry not able to post complete code.