Develop Reference

In WPF Can I have a button event in the MainWindow.xaml reference code in my own class? [duplicate]

On a button's click, i want it to execute an event handler method that is another class apart from the window class.
I believe creating a ObjectDataProvider object which is binded to the event handler method in the other class, then binding said object to the Click event would do the trick, but it didn't.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using System.Windows.Media.Animation;
using System.Windows.Threading;
using System.Data.SqlClient;
namespace LoginNS
{
/// <summary>
/// Interaction logic for Window1.xaml
/// </summary>
public partial class LoginWindow : Window
{
public LoginWindow()
{
InitializeComponent();
}
}
public class SQLServerClass
{
public void ConnectSQLServer(object sender, RoutedEventArgs e)
{
try
{
SqlConnection conn = new SqlConnection("Data Source=tcp:172.16.1.71;Initial Catalog=Sample;User ID=sa;Password=hbkrko");
conn.Open();
MessageBox.Show("success");
}
catch
{
MessageBox.Show("db error");
}
}
}
}
Here is the resource and how i'm using it which is incorrect because i get an error message:
<ObjectDataProvider x:Key="loginFunction" ObjectType="{x:Type local:SQLServerClass}" MethodName="ConnectSQLServer"/>
<Grid DataContext="{Binding Path=LoginNS}" Width="400" Height="200">
<Button x:Name="LoginButton" Style="{StaticResource LoginButton}" Click="{Binding Source={StaticResource loginFunction}}"/>
</Grid>
Immediate run-time error:
Additional information: 'Provide value on 'System.Windows.Data.Binding' threw an exception.' Line number '24' and line position '75'.

ObjectDataProvider is used to create object instances that can be used as binding source. In your case ConnectSQLServer method does not return any object that can be used for binding.
The best option for your scenario is to use RelayCommand. You can read about how to achieve this at http://www.codeproject.com/Articles/126249/MVVM-Pattern-in-WPF-A-Simple-Tutorial-for-Absolute
In your case, with RelayCommand your SQLServerClass will be something like this
public class SQLServerClass
{
public SQLServerClass()
{
LoginCommand = new RelayCommand<object>(LoginCommandExecute, LoginCommandCanExecute);
}
public void ConnectSQLServer(object sender, RoutedEventArgs e)
{
try
{
SqlConnection conn = new SqlConnection("Data Source=tcp:172.16.1.71;Initial Catalog=Sample;User ID=sa;Password=hbkrko");
conn.Open();
MessageBox.Show("success");
}
catch
{
MessageBox.Show("db error");
}
}
public ICommand LoginCommand { get; set; }
private void LoginCommandExecute(object arg)
{
ConnectSQLServer(this, new RoutedEventArgs());
}
private bool LoginCommandCanExecute(object arg)
{
return true;
}
}
And your XAML
<Window.Resources>
<ObjectDataProvider x:Key="loginFunction" ObjectType="{x:Type local:SQLServerClass}"/>
</Window.Resources>
<Grid>
<Grid Width="400" Height="200">
<Button x:Name="LoginButton" Command="{Binding Path=LoginCommand, Source={StaticResource loginFunction}}"/>
</Grid>
</Grid>
Note that you can use the MvvmLight library. It already contains an implementation of the RelayCommand class and other useful classes for WPF MVVM application.

Why can't you use this:
InitializeComponent();
sqlServerInstance = new SQLServerClass();
LoginButton.Click += MainConnectSQLServer()
And
private void MainConnectSQLServer(object sender, RoutedEventArgs e)
{
sqlServerInstance.ConnectSQLServer(sender, e);
}

UserControl Data Binding retrieve value

with this simple code:
MainWindows:
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace itemcontrole_lesson
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public class TodoItem
{
public string Username { get; set; }
public int Completion { get; set; }
}
public partial class MainWindow : Window
{
List<TodoItem> items = new List<TodoItem>();
public MainWindow()
{
InitializeComponent();
items.Add(new TodoItem() { Username = "Eric", Completion = 45 });
items.Add(new TodoItem() { Username = "Maxwell", Completion = 80 });
items.Add(new TodoItem() { Username = "Sarah", Completion = 60 });
icTodoList.ItemsSource = items;
}
}
Mainwindows XAML:
<Window x:Class="itemcontrole_lesson.MainWindow"
xmlns:local="clr-namespace:itemcontrole_lesson"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<ItemsControl x:Name="icTodoList">
<ItemsControl.ItemTemplate>
<DataTemplate DataType="{x:Type local:UserControl1}">
<local:UserControl1 />
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</Grid>
</Window>
then a simple UserControle:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace itemcontrole_lesson
{
/// <summary>
/// Interaction logic for UserControl1.xaml
/// </summary>
public partial class UserControl1 : UserControl
{
public UserControl1()
{
InitializeComponent();
//String CurentUserName = ????????
//Int Progress = ????????
}
private void Button_Click(object sender, RoutedEventArgs e)
{
///hows to remove the user from items in main windows??
}
}
}
UserControle XAML
<UserControl x:Class="itemcontrole_lesson.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"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="54.181" Width="399.331">
<Grid Margin="0,0,-155,0">
<Label Content="{Binding Username}" HorizontalAlignment="Left" Margin="23,23,0,0" VerticalAlignment="Top"/>
<Button Content="Close this UC" HorizontalAlignment="Left" Margin="414,22,0,0" VerticalAlignment="Top" Width="119" Click="Button_Click"/>
<ProgressBar HorizontalAlignment="Left" Value="{Binding Completion}" Height="10" Margin="204,23,0,0" VerticalAlignment="Top" Width="154"/>
</Grid>
</UserControl>
Pressing F5 everything will bind ok if you test.
But! how I'm supposed to retrieve my variable value in my usercontrole code?
see where I put comment in UC.
1- I need at least to find a way to remove this control from UI and from Items list?.
2-I'd like access username in my control and set it into a var
any suggestion?

Solution 1:
Use Tag property of button like below:
<Button Content="Close this UC" HorizontalAlignment="Left" Margin="414,22,0,0"
VerticalAlignment="Top" Width="119" Click="Button_Click" Tag="{Binding RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}" />
Event handler:
private void Button_Click(object sender, RoutedEventArgs e)
{
var button = sender as Button;
List<object> list = (button.Tag as ItemsControl).ItemsSource.OfType<TodoItem>().ToList<object>();
list.Remove(button.DataContext);
(button.Tag as ItemsControl).ItemsSource = list;
}
Solution 2:
More elegant solution:
Create this Style in your MainWindow:
<Window.Resources>
<Style TargetType="Button">
<EventSetter Event="Click" Handler="Button_Click"/>
</Style>
</Window.Resources>
So now the Handler of any Button Click event is in the MainWindow.xaml.cs.
Then change handler definition like below:
private void Button_Click(object sender, RoutedEventArgs e)
{
var button = sender as Button;
items.Remove(button.DataContext as TodoItem);
icTodoList.ItemsSource = null;
icTodoList.ItemsSource = items;
}

MediaElement doesn't play sound (Minimum Viable Example)

I'm developing a Windows App (Windows 8.1). In my xaml I have a MediaElement linked to a .wav file in the /Assets folder. I'd like to play the sound when I click on a button, but I can't achieve it. This is a minimum viable example that reproduces the issue. Can you help me?
This is the XAML file:
<Page
x:Class="TrySoundsDesktop.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:TrySoundsDesktop"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<StackPanel Orientation="Vertical">
<TextBlock FontSize="50" HorizontalAlignment="Center">
TRY PLAY SOUND
</TextBlock>
<MediaElement x:Name="clickSound"
Loaded="clickSound_Loaded"
MediaFailed="clickSound_MediaFailed"
MediaOpened="clickSound_MediaOpened"
MediaEnded="clickSound_MediaEnded"
AudioCategory="ForegroundOnlyMedia"
Height="100"
Width="100"
Opacity="1"
Source="/Assets/applause.wav"
AutoPlay="False"
/>
<Button Click="Button_Click" Content="CLICK TO PLAY SOUND"/>
</StackPanel>
</Page>
And this is the code behind:
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
// The Blank Page item template is documented at http://go.microsoft.com/fwlink/?LinkId=234238
namespace TrySoundsDesktop
{
/// <summary>
/// An empty page that can be used on its own or navigated to within a Frame.
/// </summary>
public sealed partial class MainPage : Page
{
public MainPage()
{
this.InitializeComponent();
}
private void Button_Click(object sender, RoutedEventArgs e)
{
clickSound.Play(); //The sound doesn't play
}
private void clickSound_MediaFailed(object sender, ExceptionRoutedEventArgs e)
{
//Not fired
}
private void clickSound_MediaOpened(object sender, RoutedEventArgs e)
{
//Not fired
}
private void clickSound_MediaEnded(object sender, RoutedEventArgs e)
{
//Not fired
}
private void clickSound_Loaded(object sender, RoutedEventArgs e)
{
//THIS METHOD FIRES
}
}
}
As you can see it's a very basic example. But it doesn't work. Thank you in advance.

On a button's click event, execute event handler in another class

On a button's click, i want it to execute an event handler method that is another class apart from the window class.
I believe creating a ObjectDataProvider object which is binded to the event handler method in the other class, then binding said object to the Click event would do the trick, but it didn't.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using System.Windows.Media.Animation;
using System.Windows.Threading;
using System.Data.SqlClient;
namespace LoginNS
{
/// <summary>
/// Interaction logic for Window1.xaml
/// </summary>
public partial class LoginWindow : Window
{
public LoginWindow()
{
InitializeComponent();
}
}
public class SQLServerClass
{
public void ConnectSQLServer(object sender, RoutedEventArgs e)
{
try
{
SqlConnection conn = new SqlConnection("Data Source=tcp:172.16.1.71;Initial Catalog=Sample;User ID=sa;Password=hbkrko");
conn.Open();
MessageBox.Show("success");
}
catch
{
MessageBox.Show("db error");
}
}
}
}
Here is the resource and how i'm using it which is incorrect because i get an error message:
<ObjectDataProvider x:Key="loginFunction" ObjectType="{x:Type local:SQLServerClass}" MethodName="ConnectSQLServer"/>
<Grid DataContext="{Binding Path=LoginNS}" Width="400" Height="200">
<Button x:Name="LoginButton" Style="{StaticResource LoginButton}" Click="{Binding Source={StaticResource loginFunction}}"/>
</Grid>
Immediate run-time error:
Additional information: 'Provide value on 'System.Windows.Data.Binding' threw an exception.' Line number '24' and line position '75'.

ObjectDataProvider is used to create object instances that can be used as binding source. In your case ConnectSQLServer method does not return any object that can be used for binding.
The best option for your scenario is to use RelayCommand. You can read about how to achieve this at http://www.codeproject.com/Articles/126249/MVVM-Pattern-in-WPF-A-Simple-Tutorial-for-Absolute
In your case, with RelayCommand your SQLServerClass will be something like this
public class SQLServerClass
{
public SQLServerClass()
{
LoginCommand = new RelayCommand<object>(LoginCommandExecute, LoginCommandCanExecute);
}
public void ConnectSQLServer(object sender, RoutedEventArgs e)
{
try
{
SqlConnection conn = new SqlConnection("Data Source=tcp:172.16.1.71;Initial Catalog=Sample;User ID=sa;Password=hbkrko");
conn.Open();
MessageBox.Show("success");
}
catch
{
MessageBox.Show("db error");
}
}
public ICommand LoginCommand { get; set; }
private void LoginCommandExecute(object arg)
{
ConnectSQLServer(this, new RoutedEventArgs());
}
private bool LoginCommandCanExecute(object arg)
{
return true;
}
}
And your XAML
<Window.Resources>
<ObjectDataProvider x:Key="loginFunction" ObjectType="{x:Type local:SQLServerClass}"/>
</Window.Resources>
<Grid>
<Grid Width="400" Height="200">
<Button x:Name="LoginButton" Command="{Binding Path=LoginCommand, Source={StaticResource loginFunction}}"/>
</Grid>
</Grid>
Note that you can use the MvvmLight library. It already contains an implementation of the RelayCommand class and other useful classes for WPF MVVM application.

Why can't you use this:
InitializeComponent();
sqlServerInstance = new SQLServerClass();
LoginButton.Click += MainConnectSQLServer()
And
private void MainConnectSQLServer(object sender, RoutedEventArgs e)
{
sqlServerInstance.ConnectSQLServer(sender, e);
}

WPF - Unable to set properties of dynamically added User Control via deserialization

File des.txt --> this file is deserialized to xaml tree
<NewLabel NewText="some new text" LabelText="yes" xmlns="clr-namespace:WpfPractice;assembly=WpfPractice" xmlns:av="http://schemas.microsoft.com/winfx/2006/xaml/presentation"><av:Grid><av:Canvas><av:TextBox Width="100" Height="30">yes</av:TextBox></av:Canvas></av:Grid></NewLabel>
Mainwindow.xaml
<Window x:Class="WpfPractice.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfPractice"
Title="MainWindow"
Width="525"
Height="350">
<Grid Name="theGrid">
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<Button Grid.Row="1"
Width="50"
Height="25"
Click="Button_Click_2"
Content="Click" />
</Grid>
MainWindow.xaml.cs
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Markup;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Xml;
namespace WpfPractice
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
NewLabel someNewLabel;
public MainWindow()
{
InitializeComponent();
someNewLabel = (NewLabel)DeserializeXaml(File.ReadAllText(#"D:\des.txt"));
theGrid.Children.Add(someNewLabel);
}
void Serialize()
{
NewLabel theNewLabel = new NewLabel();
theNewLabel.NewText = "some new text";
string xamlString = XamlWriter.Save(theNewLabel);
XmlReader reader = XmlReader.Create(new StringReader(xamlString));
UIElement copy = XamlReader.Load(reader) as UIElement;
}
private void Button_Click_2(object sender, RoutedEventArgs e)
{
someNewLabel.LabelText = "new value";
someNewLabel.SetLabelValue("asdfsadgsafgreg");
//Serialize();
}
public object DeserializeXaml(string xaml)
{
StringReader stringReader = new StringReader(xaml);
XmlReader xmlReader = XmlReader.Create(stringReader);
return System.Windows.Markup.XamlReader.Load(xmlReader);
}
}
}
NewLabel.xaml
<UserControl x:Class="WpfPractice.NewLabel"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
d:DesignHeight="300"
d:DesignWidth="300"
mc:Ignorable="d">
<Grid Name="theGrid">
</Grid>
NewLabel.xaml.cs
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace WpfPractice
{
/// <summary>
/// Interaction logic for NewLabel.xaml
/// </summary>
public partial class NewLabel : UserControl, INotifyPropertyChanged
{
public static DependencyProperty NameProperty =
DependencyProperty.Register("NewText",
typeof(string),
typeof(NewLabel),
new PropertyMetadata(String.Empty));
public string NewText
{
get { return (string)GetValue(NameProperty); }
set { SetValue(NameProperty, value); }
}
private string _labelText = "yes";
public string LabelText
{
get
{
return _labelText;
}
set
{
_labelText = value;
OnPropertyChanged("LabelText");
}
}
Label theLabel;
public NewLabel()
{
InitializeComponent();
theLabel = new Label();
theLabel.Height = 30;
theLabel.Width = 100;
theLabel.Content = "old value";
Canvas theCanvas = new Canvas();
theCanvas.Children.Add(theLabel);
theGrid.Children.Add(theCanvas);
Binding b = new Binding("LabelText");
b.Source = this;
theLabel.SetBinding(TextBox.TextProperty, b);
theLabel.MouseDoubleClick += theLabel_MouseDoubleClick;
this.DataContext = this;
}
void theLabel_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{
MessageBox.Show("clicked!");
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(propertyName));
}
public void SetLabelValue(string val)
{
theLabel.Content = val;
}
}
}
Question:
Both these statements in MainWindow.xaml.cs
someNewLabel.LabelText = "new value";
someNewLabel.SetLabelValue("asdfsadgsafgreg");
do not work. In other words, I am unable to set the textbox property to "new value"

You are creating the binding in NewLable constructor, but then you load a new visual tree from a file which overrides the original one. That why you cant update the label nor by binding neither by setting the value directly because its not in the visual tree anymore.