Cannot drag text into a WPF window - c#

I'm trying to set up a WPF window so that it can accept different types of data via Drag and Drop. If I make a new project and set the window to the following:
<Window x:Class="DropShare.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="300" Width="300" AllowDrop="True" DragEnter="Window_DragEnter">
<Grid>
</Grid>
</Window>
And set the code-behind to:
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
}
private void Window_DragEnter(object sender, DragEventArgs e)
{
}
}
I only ever get DragEnter firing for files. It never fires for anything else - text, images, etc.
Is there something I'm missing? All the tutorials I've read have seemed to suggest this is all that's needed as the DragEnter event handler let's me state what I accept.

So your code works fine for me. But try this...
In your Window:
<Label Background="Purple" HorizontalAlignment="Center" VerticalAlignment="Center" Content="Drag from here!" MouseDown="Label_MouseDown"/>
and in your code behind:
private void Label_MouseDown(object sender, MouseButtonEventArgs e)
{
DragDrop.DoDragDrop(this, "This is just a test", DragDropEffects.All);
}
Then drag from the label into the window and see if your event fires.
If this works, it may have something to do with the permissions level between Visual Studio and your outside environment (possibly).
See:
https://superuser.com/questions/59051/drag-and-drop-file-into-application-under-run-as-administrator

In WPF drag and drop feature always has to deal with DragDrop Class, Please check here how to do drag and drop across applications

Related

How can I capture WPF events from a Winforms app

I have an WPF User control which is is hosted in an Elementhost. I use elementhost to include an WPF user control in my classical Windows forms app.
Now, from Windows forms side I am trying to capture the mouseDown event that is produced in an WPF label but I don't know how to do it.
Any ideas?
A case might be able to help you. The winform form calls the wpf control.
Create a WPF custom control. The xaml code of the control is as follows.
<Grid>
<Image Margin="10,10,10,90" x:Name="img" Stretch="Uniform" Opacity="1">
<Image.BitmapEffect>
<DropShadowBitmapEffect Opacity="1" />
</Image.BitmapEffect>
</Image>
<TextBox Background="Transparent" Foreground="White" Height="40" FontSize="32" Margin="44,0,56,36" x:Name="txtBox1" Opacity="0.5" Text="" VerticalAlignment="Bottom" /> </Grid>
You need to add the corresponding function to set the effect. The code is as follows.
public void SetSource(string fileName)
{
img.Source = new BitmapImage(new Uri(fileName) );
}
public void SetOpacity(double opacity)
{
img.Opacity = opacity;
}
//
public string GetText()
{
return txtBox1.Text;
}
Create a Winform application and add a reference, otherwise the control will not work properly. The list of references is pictured below.
Regenerate the solution. On the left toolbar, a WPF control appears and drag it to the form.
Use the button control in the winform project to call the corresponding function.
private void button1_Click(object sender, EventArgs e)
{
((UserControl1)elementHost1.Child).SetSource(#"C:\Users\Admin\Pictures\Saved Pictures\9837f99502eba3d01d4fb671cab20c15.jpg");
}
private void button2_Click(object sender, EventArgs e)
{
((UserControl1)elementHost1.Child).SetOpacity(0.5);
}
private void button3_Click(object sender, EventArgs e)
{
string text = ((UserControl1)elementHost1.Child).GetText();
label1.Text = text;
}
Test items: The left side is the traditional Winform control. The right side is the imported WPF control. You can clearly see the "translucent" effect of the picture.
Not sure what exactly you're trying to achieve. Below is a simple example.You can edit the MouseDown event of the UserControl as needed.
If there is a problem, please make your problem clearer and show me the complete code sample that can reproduce your problem for analysis.
UserControl:
<Grid>
<Label x:Name="label" Content="Label" MouseDown="label_MouseDown" Background="AliceBlue" Width="300" Height="200" />
</Grid>
private void label_MouseDown(object sender, MouseButtonEventArgs e)
{
MessageBox.Show("hello");
}
Add the UserControl reference in the WinForms project, drag and drop the UserControl on the Form1 designer after rebuilding the WinForms project.
The result of running the project and clicking the Label in the UserControl is shown in the figure.

C#/AvaloniaUI - Click a button and change Text

I am very new to AvaloniaUI.
I am really struggling to change a text when I click a button.
Here is my code:
<Window xmlns="https://github.com/avaloniaui"
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"
mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
x:Class="ReadyForWar_Launcher.MainWindow"
Title="ReadyForWar_Launcher">
<StackPanel>
<TextBlock Name="TestBlock">Show my text here!</TextBlock>
<Button Command="{Binding RunTheThing}" CommandParameter="Hello World">Change the Text!</Button>
</StackPanel>
</Window>
Here is my MainWindow.xaml.cs:
using Avalonia;
using Avalonia.Controls;
using Avalonia.Markup.Xaml;
namespace ReadyForWar_Launcher
{
public class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
#if DEBUG
this.AttachDevTools();
#endif
}
private void InitializeComponent()
{
AvaloniaXamlLoader.Load(this);
}
public void RunTheThing()
{
}
}
}
Inside RunTheThing I don't know how can I select the TextBlock with Name="TestBlock" and change the text to "Hello World".
Can you please help me out on this ?
There are two approaches, the recommended one and straightforward one.
Recommended: Use MVVM pattern. Create a view model with ButtonTextProperty and RunTheThing command, make the command to change the property, assign that model to the DataContext and bind your button text and command to view model properties. The MVVM approach is basically the same as in WPF, so you can use documentation and tutorials from there (that applies to most of the Avalonia, BTW). For example, here is a good one (not advertising, 4th link from google).
Straightforward (aka winforms-way): add x:Name="MyButton" to your button and use this.FindControl<Button>("MyButton") after calling AvaloniaXamlLoader.Load(this);. This will give you a Button reference that you can manipulate from code. Instead of using commands, you can just subscribe to the click handler directly from codebehind, add public void MyButton_OnClick(object sender, RoutedEventArgs args){} to your MainWindow class and add replace Command and CommandParameter with Click="MyButton_OnClick". That way button click will trigger your event handler.
Note, that the second approach doesn't scale well with the application size and suffers from code complexity when handling lists.

WPF call Window_Closing event from code behind

Recently I have been experimenting with WPF. I was building a little program, but then I stumbled across a little problem. I tried to call the Window_Closing method from the code behind, it told me that I needed to give it cerntain parameters, but I don't have those parameters in the method I am trying to call it from.
This is my code:
private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
// My Window Closing code
}
private void Application_Exit(object sender, RoutedEventArgs e)
{
// Here is where I am trying to call it, giving a empty parameter with it.
// But it doesn't seem to work.
Window_Closing(null, EventArgs.Empty)
}
What I want
If a cenrtain button is called, I want the Window_Closing event to be called.
Anyone who knows the solution?
In your Designer, click on the Button and open its property window. There you select the "Events" - the "lightning" and choose the Click event to execute your Window_Closing method. There is a drop down in which you should be able to select it. If not, enter your method name there and press "Enter" to let VS generate the code-behind method.
Add "Window_Closing" & "Close_Click" in the XAML file (MainWindow.xaml) as follows.
<Window x:Class="WpfApp1.MainWindow"
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"
xmlns:local="clr-namespace:WpfApp1"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800" Closing="Window_Closing">
<Grid>
<Button x:Name="Close" Content="Close" Click="Close_Click" Width="100" Height="30"/>
</Grid>
Then in the code behind file (MainWindow.xaml.cs) add the following code. Here the window close command is called from the button click event handler which in turn closes the window, and then the 'Window_Closing' event handler will be automatically called.
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
}
private void Close_Click(object sender, RoutedEventArgs e)
{
Close();
}
}
Just close the window. Then the event will be called automatically, thats what it is there for to begin with.
And as it seems, you try calling it from your Application_Exit, which closes all the windows ... so .... What is your problem?
Just put a breakpoint in the Window_Closing and see, that is executed automatically. If not, maybe you should add the eventhander to all the windows Window_Closing events.

KeyDown event not raising from a grid

Here I have sample window with a grid. I need to capture event when key is pressed. But it is not raising when I click grid area and then press key. It will work only if Textbox is focused. I know it will work if I capture it from Window. But I have other application with few usercontrols and I need to capture it from distinct ones. I tried to set Focusable.false for Window and true for Grid but it not helps.
Any solutions?
<Window x:Class="Beta.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525" Closed="Window_Closed_1" Focusable="False">
<Grid KeyDown="Grid_KeyDown_1" Focusable="True">
<TextBox x:Name="tbCount" HorizontalAlignment="Left" Height="35" Margin="310,49,0,0" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="83"/>
</Grid>
Right this is weird. This is clearly a focus problem, still I can not understand why the grid do not take Focus, even when we click on it.
Though there is a workaround: create an handler for the loaded event of the grid:
<Grid x:Name="theGrid" KeyDown="Grid_KeyDown_1" Focusable="True" Loaded="TheGrid_OnLoaded">
And then force focus in your code behind:
private void TheGrid_OnLoaded(object sender, RoutedEventArgs e)
{
theGrid.Focus();
}
Your keydown event will work after that.
Hope it helps.
I had the same issue with a Universal Windows Platform (UWP) app. I attached the event to a grid in XAML but it would only work when the focus was on the TextBox. I found the answer (not just a workaround) on MSDN: https://social.msdn.microsoft.com/Forums/en-US/56272bc6-6085-426a-8939-f48d71ab12ca/page-keydown-event-not-firing?forum=winappswithcsharp
In summary, according to that post, the event won't fire because when focus to the TextBox is lost, it's passed higher up so the Grid won't get it. Window.Current.CoreWindow.KeyDown should be used instead. I've added my event handlers to the page loaded event like this:
private void Page_Loaded(object sender, RoutedEventArgs e)
{
Window.Current.CoreWindow.KeyDown += coreWindow_KeyDown;
Window.Current.CoreWindow.KeyUp += CoreWindow_KeyUp;
}
This works as expected for me.
I tried using the Focus Method too, to no avail, until I set the Focusable property to true ( It was default to False. )
I had the same problem, I've used PreviewKeyDownevent and it worked for me.

UserControl Events are very slow

I have recently started to move my user controls in DLLs. These controls usually look something like this:
<UserControl x:Class="DialogBase.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"
DataContext="{Binding RelativeSource={RelativeSource Self}}">
<Grid>
<Button Content="OK" Click="OkButton_Click"/>
</Grid>
</UserControl>
I want to able to use every button in the control like in a standard control. For example when somebody uses the control above, he should be able to handle the click event in an own method like this:
<lib:UserControl1
OkButtonClick="MyCostomClickMethod"
/>
I usualy achieve this like this: (code-behind file of user control)
public static RoutedEvent OkButtonClickEvent = EventManager.RegisterRoutedEvent("OkButtonClick", RoutingStrategy.Bubble, typeof(RoutedEventHandler), typeof(UserControl1));
public event RoutedEventHandler OkButtonClick
{
add
{
AddHandler(OkButtonClickEvent, value);
}
remove
{
RemoveHandler(OkButtonClickEvent, value);
}
}
private void OkButton_Click(object sender, RoutedEventArgs e)
{
RaiseEvent(new RoutedEventArgs(OkButtonClickEvent));
}
This works fine but very slow. The delay between a click and the resulting action can be up to a second. Can somebody tell me if there is a faster or in any way better way to do this?
I would create a Command in the class the you actually want the event. Then bind the Button Command to it. You can create your own Command or use something like a DelegateCommand

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