Develop Reference

code generated control not found in code wpf

I created control in WPF from C# and find that control on button click but not found
public MainWindow()
{
InitializeComponent();
TextBox textBox = new TextBox();
textBox.Name = "childTextBox";
TextBoxes.Add(textBox);
StackPanelParent.Children.Add(textBox);
}
private void Button_Click(object sender, RoutedEventArgs e)
{
var findTextBox = (TextBox)this.FindName("childTextBox");
//it's give null
}
XAML Code
<StackPanel Margin="152,103,191,56">
<Label Name="Loader" Visibility="Collapsed">Loader</Label>
<Button Content="Click Me" HorizontalAlignment="Left" Margin="342,199,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click"/>-->
<StackPanel Name="StackPanelParent">
</StackPanel>
<Button Click="Button_Click">Check</Button>
</StackPanel>

When you dynamically create a component they cannot be found by FindName unless you register them first like this:
public MainWindow()
{
InitializeComponent();
TextBox textBox = new TextBox();
textBox.Name = "childTextBox";
TextBoxes.Add(textBox);
StackPanelParent.Children.Add(textBox);
// register name
RegisterName(textBox.Name, textBox);
}

Get TextBlock inside Button

I have a Button with a TextBlock embedded inside. When the Button is clicked, I want to be able to fetch the TextBlock inside it and modify it's members.
Here is how my button is setup:
<Button Click="Select_Click" Style="{StaticResource ButtonStyle}" HorizontalAlignment="Left" Padding="0,20,20,20">
<TextBlock Text="My text" FontSize="20" Style="{StaticResource TextBlockStyle}"/>
</Button>
In my code behind I want to be able to access the embedded TextBlock:
public void Select_Click(object sender, RoutedEventArgs e)
{
// Get the `TextBlock` from `sender` here
}
I've taken a look at the visual tree of the Button but I'm not seeing the TextBlock. I called GetVisualChildren() on the Button but I only see a Grid and no way to get to the Textblock.

The content of the Button is stored in its Content property and in your case, the TextBlock is the content of the Button.
public void Select_Click(object sender, RoutedEventArgs e)
{
Button button = (Button)sender;
TextBlock textBlock = (TextBlock)button.Content;
}

Just do some casting and it's pretty simple
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
Establish_handlers();
}
void Establish_handlers()
{
Mybutton.Click += Mybutton_Click;
}
private void Mybutton_Click(object sender, RoutedEventArgs e)
{
Button clicked_button = (Button)sender;
TextBlock desired_text = (TextBlock)clicked_button.Content;
Textbox_Show_Button_Content.Text = desired_text.Text;
}
}
<StackPanel>
<Button x:Name="Mybutton">
<TextBlock>Hello</TextBlock>
</Button>
<TextBox x:Name="Textbox_Show_Button_Content"></TextBox>
</StackPanel>

Delete Row In a DataGrid for a WPF browser Application

I m trying to build a WPF browser application after using a lot WinForms.
I don't find out the way to delete a row in my dataGrid.
The update and insert part work fine.
I've read a lot of answers about ObservableCollection, but I think it s not suitable in my case.
I tried this on:
foodSupplierDataGrid.Items.Remove(foodSupplierDataGrid.SelectedItem);
But it gives an error.
Operation is not valid while ItemsSource is in use. Access and modify elements with ItemsControl.ItemsSource instead.
So what should i do?
XAML
<
<Page
<Page.Resources>
<local:larotis_general_testDataSet x:Key="larotis_general_testDataSet"/>
<CollectionViewSource x:Key="foodSupplierViewSource" Source="{Binding foodSupplier, Source={StaticResource larotis_general_testDataSet}}"/>
</Page.Resources>
<Grid Background="#FF066E19" Margin="-463,-198,-465,-234">
<dg:DataGrid x:Name="foodSupplierDataGrid" AutoGenerateColumns="True" EnableRowVirtualization="True" ItemsSource="{Binding}" Margin="296,134,288,224" RowDetailsVisibilityMode="VisibleWhenSelected" Loaded="foodSupplierDataGrid_Loaded" CanUserDeleteRows="True" />
<Menu>
...
</Menu>
<Button x:Name="Delete" Content="Button" HorizontalAlignment="Left" Margin="933,836,0,0" VerticalAlignment="Top" Width="75" Click="Delete_Click"/>
</Grid>
</Page>
The code behind
public partial class Supplier : Page
{
larotis_general_testDataSetTableAdapters.foodSupplierTableAdapter adapter = new larotis_general_testDataSetTableAdapters.foodSupplierTableAdapter();
larotis_general_testDataSet dataset = new larotis_general_testDataSet();
public Supplier()
{
InitializeComponent();
}
private void foodSupplierDataGrid_Loaded(object sender, RoutedEventArgs e)
{
adapter.Fill(dataset.foodSupplier);
this.DataContext = dataset.foodSupplier.DefaultView;
dataset.foodSupplier.foodSupplierRowChanged += new larotis_general_testDataSet.foodSupplierRowChangeEventHandler(SupplierRowModified);
dataset.foodSupplier.foodSupplierRowDeleted += new larotis_general_testDataSet.foodSupplierRowChangeEventHandler(SupplierRowModified);
}
void SupplierRowModified(object sender, larotis_general_testDataSet.foodSupplierRowChangeEvent e)
{
adapter.Update(dataset.foodSupplier);
}
private void Delete_Click(object sender, RoutedEventArgs e)
{
}
}

Finally found it by myself.
It was quite simple.
private void Delete_Click(object sender, RoutedEventArgs e)
{
dataset.foodSupplier.DefaultView.Delete(foodSupplierDataGrid.SelectedIndex);
this.DataContext = dataset.foodSupplier.DefaultView;
}

How to navigate to other page with button in WPF

I have a second .xaml page set up under the name Page2.xaml and I want to make it so that when my button is clicked, the user is taken to Page2.xaml
I have this for my button inside of my Page1.xaml:
<Grid>
<Button x:Name="localModeBtn"
Style="{StaticResource MainButtonStyle}"
Content="local mode"
Click="localModeBtn_Click" />
</Grid>
And for the button event handler:
private void localModeBtn_Click(object sender, RoutedEventArgs e)
{
Uri uri = new Uri("Page2.xaml", UriKind.Relative);
this.NavigationService.Navigate(uri);
}
Upon clicking the button I receive an error that says "Cannot locate resource page2.xaml"
The thing is that Page2.xaml is in the same folder as Pag1.xaml so I can't see where I've gone wrong?

Solution to my own question:
I feel a bit silly providing a solution to my own question but thanks to Jasti's link I was able to sort my code out. As he had only posted a comment, I can't mark it as an answer, so here is the solution.
I changed the NavigationWindow to a Window and inserted:
<DockPanel>
<Frame x:Name="_NavigationFrame" NavigationUIVisibility="Hidden" />
</DockPanel>
And within the constructor of the MainWindow.xaml.cs I added:
_NavigationFrame.Navigate(new Page1());
Then the last step was to adjust the button event handler to:
this.NavigationService.Navigate(new Uri("Pages/Page2.xaml", UriKind.Relative));

You should use this, this worked for me:
var Page2= new Page2(); //create your new form.
Page2.Show(); //show the new form.
this.Close(); //only if you want to close the current form.
There is a variable type of a page with the page.xaml right name in your solution.
after that, you should use its methods to do it functionally.

Use any container and bind the content to any property in your viewmodel or codebehind.
After that you just have to update the property by setting a new page and call the PropertyChanged-event (see INotifyPropertyChanged interface). This will update the content of your container and you can display anything you want.

In case you want a separate window
NavigationWindow navWIN = new NavigationWindow();
navWIN.Content = new pageWFbchAdmin();
navWIN.Show();
//winBchAdmin.ShowDialog();

You don't need any C# code for this, just do it in XML:
<Button Content="local mode"
Command="NavigationCommands.GoToPage"
CommandParameter="/Page2.xaml"/>
(Reformatted code not tested)

private void Navigate_Click(object sender, RoutedEventArgs e)//By Prince Jain
{
this.NavigationService.Navigate(new Uri("Page3.xaml", UriKind.Relative));
}

My solution was adding a frame in the main window MainWindow.xaml
<Frame Name="Main" Content="" Margin="127,0,0,0" Background="#FFFFEDED" />
For navigation:
1- Navigating from the main windows on button click:
private void Button_Click(object sender, RoutedEventArgs e)
{
// navigate to pages/projects.xaml inside the main frame
Main.Content = new MyProject.Pages.Projects();
}
2- In case of navigation from the page inside a frame ex Projects.xaml
// declare a extension method in a static class (its your choice if you want to reuse)
// name the class PageExtensions (you can choose any name)
namespace MyProject
{
public static class PageExtensions
{
public static void NavigateTo(this Page page, string path)
{
Frame pageFrame = null;
DependencyObject currParent = VisualTreeHelper.GetParent(page);
while (currParent != null && pageFrame == null)
{
pageFrame = currParent as Frame;
currParent = VisualTreeHelper.GetParent(currParent);
}
if (pageFrame != null)
{
pageFrame.Source = new Uri(path, UriKind.Relative);
}
}
}
}
// to navigate from 'pages/projects.xaml' to another page
// heres how to call the extension on button click
this.NavigateTo("NewProject.xaml");
In addition, you can add another extension method that expects another Page object, in case you want to pass parameters to the constructor
// overloading NavigateTo
public static void NavigateTo(this Page page, Page anotherPage)
{
Frame pageFrame = null;
DependencyObject currParent = VisualTreeHelper.GetParent(page);
while (currParent != null && pageFrame == null)
{
pageFrame = currParent as Frame;
currParent = VisualTreeHelper.GetParent(currParent);
}
// Change the page of the frame.
if (pageFrame != null)
{
pageFrame.Navigate(anotherPage);
}
}
// usage
this.NavigateTo(new Pages.EditProject(id));

First of all, you'll need a frame in your window to hold the pages, so in my MainWindow.xaml I'll add a frame like this:
<Frame x:name="mainFrame"/>
Then We'll add an event listener to our navigation button in our MainWindow.xaml like this:
<Button
x:Name="navBtn"
Content="LIVE VIEW"
Click="NavBtn_Click">
</Button>
Now after we've set our window xaml up, we'll go to MainWindow.xaml.cs and write our code:
//this function should be automatically generated
private void NavBtn_Click(object sender, RoutedEventArgs e)
{
//we'll write this line, which opens our page
mainFrame.Content = new YourPage();
}
and that's it your navigation is ready!

In View (.xaml file):
<StackPanel>
<TextBlock>Outside area of frame</TextBlock>
<StackPanel Height="20" Width="400" VerticalAlignment="Top" Orientation="Horizontal">
<Button Content="Page 1" Width="200" Click="Button_Click"/>
<Button Content="Page 2" Width="200" Click="Button_Click_1"/>
</StackPanel>
<Frame Name="Main" Height="300" Width="700" Background="LightGray">
</Frame>
</StackPanel>
In code behind (.xaml.cs file):
private void Button_Click(object sender, RoutedEventArgs e)
{
Main.Content = new Page1();
}
private void Button_Click_1(object sender, RoutedEventArgs e)
{
Main.Content = new Page2();
}
Thesse two buttons will now help you to navigate between pages named Page1 and Page2. (Please take care of namespaces if the pages are present in folders or so).

Windows 8 Store App - MediaElement no longer playing Audio

I am trying to play an audio file (.wav) when a toggle button is pressed (and pause when pressed again). I had it working initially, but now I must of messed something up and am looking for help. This is how I'm doing it:
Create MediaElement in XAML
<MediaElement x:Name="myMediaElement" HorizontalAlignment="Center" VerticalAlignment="Center" PosterSource="vuvuzela.png" IsLooping="True" Source="Assets/vuvuzela.wav" Grid.Row="1" AutoPlay="False"/>
Then My ToggleButton is this:
<ToggleButton x:Name="ToggleButton" Content="Activate" HorizontalAlignment="Center" VerticalAlignment="Center" Grid.Row="2" FontSize="32" Style="{StaticResource ToggleButtonStyle1}" Checked="Tog_Checked" Unchecked="Tog_Unchecked"/>
And in my Code-behind, I have the ToggleButton's checked/unchecked handlers:
private void Tog_Checked(object sender, RoutedEventArgs e)
{
myMediaElement.Play();
}
private void Tog_Unchecked(object sender, RoutedEventArgs e)
{
myMediaElement.Pause();
}
Any ideas as to what might be going wrong or how to check it? Thanks!
EDIT: Debugged some more. Looks like the myMediaElement is not getting past the Opening state?

Apparently it was a hardware problem. My computer (MacBook running Bootcamp) was the issue. Finally found that answer in this post --> MediaElement in WinRT / Win8 does not work at all
Thanks for all the help though everyone

Is it important to you that your media element be visual like that?
Try this in your click event instead:
var _Media = new Windows.UI.Xaml.Controls.MediaElement() { AutoPlay = false };
var _Location = Windows.ApplicationModel.Package.Current.InstalledLocation;
var _Folder = await _Location.GetFolderAsync("Assets");
var _File = await _Folder.GetFileAsync("Ding.wav");
var _Stream = await _File.OpenAsync(Windows.Storage.FileAccessMode.Read);
_Media.SetSource(_Stream, _File.ContentType);
_Media.Play();

Have shown code required to play audio file. (code for playing next audio is bonus )
1.Add media element, play/pause/stop buttons to the XAML file.
<MediaElement x:Name="media" Source="Assets/page1/para1.mp3"
Grid.Column="0" Grid.Row="0" AutoPlay="True" />
<Button Click="StopMedia" Grid.Column="0" Grid.Row="1" Content="Stop" />
<Button Click="PauseMedia" Grid.Column="1" Grid.Row="1" Content="Pause" />
<Button Click="PlayMedia" Grid.Column="2" Grid.Row="1" Content="Play" />
2.Add the following code to the code-behind file:
private void StopMedia(object sender, RoutedEventArgs e)
{
media.Stop();
}
private void PauseMedia(object sender, RoutedEventArgs e)
{
media.Pause();
}
private void PlayMedia(object sender, RoutedEventArgs e)
{
media.Source = new Uri(this.BaseUri, "Assets/page1/para1.mp3");
media.Play();
}
protected override async void LoadState(Object navigationParameter, Dictionary<String, Object> pageState)
{
media.MediaEnded += media_MediaEnded;
}
private void media_MediaEnded(object sender, RoutedEventArgs e)
{
media.Source = new Uri(this.BaseUri, "Assets/page1/para2.mp3");
media.Play();
}