Develop Reference

Drag & Drop from explorer to wpf element

Everything seems to be simple and there are quite a few tutorials, but I cannot transfer data (in my case, an image) to a wpf window element. I was able to implement the transfer of an image from one element to another. But when I capture an image (for example, a desktop), when I transfer it to the desired element, the transfer option does not even appear, only a crossed-out circle and does not work out more than one event associated with drop (as if AllowDrop = false)
My code:
XAML
<Image x:Name="mainContent" Grid.Column="1" Stretch="Fill" AllowDrop="True" Drop="MainContent_Drop" />
C#
private void SpImageLeft_MouseDown(object sender, MouseButtonEventArgs e)
{
Image image = sender as Image;
DragDrop.DoDragDrop(image, image, DragDropEffects.Copy);
}
private void MainContent_Drop(object sender, DragEventArgs e)
{
Image image = (Image)e.Data.GetData(typeof(Image));
mainContent.Source = image.Source;
}
I understand that when I take an image from explorer it will be different there, something like this, but it still does not even show that you can add an image
private void MainContent_Drop(object sender, DragEventArgs e)
{
string[] arr = (string[])e.Data.GetData(DataFormats.FileDrop);
mainContent.Source = (ImageSource)new ImageSourceConverter().ConvertFromString(arr[0]);
}

The following worked for me as a Drop event handler for an Image control:
private void OnMainImageDrop(object sender, DragEventArgs e)
{
if (sender is Image image && e.Data.GetDataPresent(DataFormats.FileDrop))
{
if (e.Data.GetData(DataFormats.FileDrop) is string[] filePaths)
{
image.Source.Freeze();
string filePath = filePaths[0];
var uriSource = new Uri(filePath);
var imageSource = new BitmapImage(uriSource);
image.Source = imageSource;
}
}
}
I used a placeholder image to make sure the image had a size and served as a mouse hover surface.
XAML:
<Image x:Name="MainImage" Grid.Row="1"
Source="Images/DotNetLogo.png"
Stretch="Uniform"
AllowDrop="True" Drop="OnMainImageDrop"/>

How to get image location to Label or Entry in Xamarin

in .xaml
<Image x:Name="image">
<Image.GestureRecognizers>
<TapGestureRecognizer Tapped="GetImageLocationFromExternalCard"/>
</Image.GestureRecognizers>
</Image>
<Label x:Name="fileLocation"/>
in .xaml.cs
private void GetImageLocationFromExternalCard(object sender, EventArgs e)
{
// what can i write is here
image.Source = fileLocation.Text;
}
I want to make is like pick an image file from memory card and send as string location to label text.

use MediaPicker
var photo = await MediaPicker.PickPhotoAsync();
image.Source = photo.FullPath;

C# Add buttons with images and handlers

I have a simple problem, but since it's the first time I'm using C#/XAML here I go.
The XAML file contains a StackPanel to which I want to add clickable images at runtime.
<StackPanel x:Name="grid_" Orientation="Horizontal" Margin="10 0 10 0" VerticalAlignment="Center">
</StackPanel>
I didn't succeed in creating a click event on those images, and I've read I could try with buttons, changing their background. This is my code:
for (int i = 0; i < 20; i++)
{
Button j = new Button();
//Image j = new Image();
//j.Source = new BitmapImage(new Uri("Images/my_thumb.png", UriKind.Relative));
var brush = new ImageBrush();
j.BackgroundImage = brush;
//j.MouseDown += new RoutedEventHandler(this.changeImage);
grid_.Children.Add(j);
Grid.SetRow(j, i);
}
Now, how can I change the button image, and add a handler to retrieve which button has been clicked? The error I'm getting is
Error 3 'System.Windows.Controls.Button' does not contain a definition for 'BackgroundImage' and no extension method 'BackgroundImage' accepting a first argument of type 'System.Windows.Controls.Button' could be found (are you missing a using directive or an assembly reference?)
You can see from my comments in the code that I am still retaining the plain image approach, just to be sure: in case you know how to make my images clickable, please tell me :)
I can settle down for an event handler that could just retrieve the button image source file name, in case.
Can you point me in the right direction? Remember I am a complete newbie! :)
Thanks!

You could use the Click event
j.Click += new EventHandler(onButtonClick);
And then in the event handler
void onButtonClick(Object sender, EventArgs e)
{
var clickedButton = sender as Button;
// do your stuff..
}

XAML
<Button x:Name="button" Content="Button1" HorizontalAlignment="Left" Margin="400,20,0,0" VerticalAlignment="Top" RenderTransformOrigin="-1.258,-5" Click="Button_Click" Height="80" Width="80"/>
C#
private void Button1_Click(object sender, RoutedEventArgs e)
{
button1.Background = new ImageBrush { ImageSource = new BitmapImage(new Uri("ms-appx:/Images/timerg.png", UriKind.RelativeOrAbsolute)) };
}
or C#
private void Button1_Click(object sender, RoutedEventArgs e)
{
BitmapImage bmp = new BitmapImage();
Uri u = new Uri("ms-appx:/Images/timer.png", UriKind.RelativeOrAbsolute);
bmp.UriSource = u;
// NOTE: change starts here
Image i = new Image();
i.Source = bmp;
button1.Content = i;
}

How to add grid background Image in c#

I am trying to change images source or image background in c# when a button is click with xaml design UI.
<Grid x:Name="gridimage">
<Image x:Name="Image" stretch="Fill"/>
</Grid>
private void Button1_click(object sender, RoutedEventArgs e)
{
// NOT WORKING FOR ME
gridimage.Source = new BitmapImage (new Uri("location"));
gridimage.Background = ?
}

Assumed that there is an Assets folder in your Visual Studio project that contains an image file 2.png, and that the image file's Build Action is set to Resource, you would create a BitmapImage in code behind from a Pack URI like this:
var uri = new Uri("pack://application:,,,/Assets/2.png");
var bitmap = new BitmapImage(uri);
Then you would use the BitmapImage as Source of your Image control:
Image.Source = bitmap;
Or use it with an ImageBrush as Background of your Grid:
gridimage.Background = new ImageBrush(bitmap);

Drag and drop an image in WPF

I'm trying to drag and drop an image from one spot on the canvas to another (should be relatively simple), but can't figure it out. The image which I want to move has the following XAML:
<Image Height="28" HorizontalAlignment="Left" Margin="842,332,0,0" Name="cityImage" Stretch="Fill" VerticalAlignment="Top" Width="42" Source="/Settlers;component/Images/city.png" MouseLeftButtonDown="cityImage_MouseLeftButtonDown" MouseMove="cityImage_MouseMove" MouseLeftButtonUp="cityImage_MouseLeftButtonUp"/>
The code is as follows:
bool isDragging = false; Point initMousePos; private void cityImage_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) {
isDragging = true;
initMousePos = e.GetPosition(theGrid); } private void cityImage_MouseMove(object sender, MouseEventArgs e) {
if (isDragging)
{
Image image = sender as Image;
Canvas.SetTop(image, initMousePos.X);
Canvas.SetLeft(image, initMousePos.Y);
image.Visibility = System.Windows.Visibility.Visible;
} }
private void cityImage_MouseLeftButtonUp(object sender, MouseButtonEventArgs e) {
isDragging = false; }

What I do to accomplish what you want is to use
System.Windows.Controls.Primitives.Thumb
as the Root of a UserControl and set the ControlTemplate to display an image (within a border but it should work without as well), something like:
<Thumb Name="myRoot" DragDelta="MyRootDragDelta">
<Thumb.Template>
<ControlTemplate>
<Image ... >
... see below ...
</Image>
</ControlTemplate>
</Thumb.Template>
</Thumb>
Also, I bind the Source of the Image to a property of the class:
<Image.Source>
<Binding Path="ImageSource" RelativeSource=
{RelativeSource FindAncestor,
AncestorType=my:MyImageControl, AncestorLevel=1}" />
</Image.Source>
The UserControl has a named TranslateTransform (let's say translateTransform) whose properties X and Y are to be set in the DragDelta event handler:
private void MyRootDragDelta(object sender, DragDeltaEventArgs e)
{
translateTransform.X += e.HorizontalChange;
translateTransform.Y += e.VerticalChange;
}
Don't forget to add:
public ImageSource ImageSource { get; set; }
Hope this helps. If anything's unclear feel free to ask further.

You want to set the Left and Top properties of the Canvas to something other than the initial position. In the MouseMove handler you have to get the position relative to the parent. Also; make sure the parent element is a canvas and not a grid. You have a pretty big left and top margin on the image, aswell as a control with the variable name "theGrid".