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;

Get url from image source and launch it (UWP)

I have UWP app where I have Image with url source.
Here is xaml code:
<Image x:Name="Image" HorizontalAlignment="Left" Height="200" Width="200" Tapped="Image_Tapped">
<Image.Source>
<BitmapImage UriSource="{Binding data.thumbnail}" />
</Image.Source>
</Image>
I created Tapped event handler
Here is code
private void Image_Tapped(object sender, TappedRoutedEventArgs e)
{
var source = Image.SourceProperty.ToString();
Debug.WriteLine(source);
}
But it seems not right.
How I can get ImageSource and launch this url(Image source is url) in browser?

You need the Launcher class.
private async void Image_Tapped(object sender, TappedRoutedEventArgs e)
{
if (((Image)sender).Source is BitmapImage bitmapImage)
{
var uri = bitmapImage.UriSource;
// Launch the URI
var success = await Windows.System.Launcher.LaunchUriAsync(uri);
if (success)
{
// URI launched
}
else
{
// URI launch failed
}
}
}
Also note since you might want to decode the image to render size since you have already specified the image size (i.e. 200x200) to save a bit of memory. You don't have to do this if you are using Image.Source directly.
<BitmapImage DecodePixelWidth="200" DecodePixelHeight="200" ... />

Why can change BitmapImage source only once?

Please, help is needed. In this code have to be stupid mistake but what it is? If I run this very simple code I can load and change bitmap image only once. At first time it runs ok but if I like to change the image again (press the button) the first image remains. Why?
XAML
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<StackPanel>
<Button x:Name="AddProfilePicture" HorizontalAlignment="Center" Click="AddProfilePicture_Click">
<Grid Width="200" Height="200">
<Ellipse Width="200" Height="200">
<Ellipse.Fill>
<ImageBrush x:Name="ImageBrush_ProfilePicture" Stretch="UniformToFill"/>
</Ellipse.Fill>
</Ellipse>
</Grid>
</Button>
</StackPanel>
</Grid>
CODE
private async void AddProfilePicture_Click(object sender, RoutedEventArgs e)
{
FileOpenPicker profilePictureFilePicker = new FileOpenPicker();
profilePictureFilePicker.ViewMode = PickerViewMode.Thumbnail;
profilePictureFilePicker.SuggestedStartLocation = PickerLocationId.PicturesLibrary;
profilePictureFilePicker.FileTypeFilter.Add(".jpg");
StorageFile userSelectedProfilePicture = await profilePictureFilePicker.PickSingleFileAsync();
//MAKE SURE U HAVE THIS FILE (ProfilePicture.jpg) IN FOLDER ALREADY....
StorageFile destinationFileImage = await StorageFile.GetFileFromPathAsync(ApplicationData.Current.LocalFolder.Path + #"\" + "ProfilePicture.jpg");
await userSelectedProfilePicture.CopyAndReplaceAsync(destinationFileImage);
Uri profilePictureBitmapURI = new Uri(ApplicationData.Current.LocalFolder.Path + #"\" + "ProfilePicture.jpg");
BitmapImage profilePictureBitmap = new BitmapImage(profilePictureBitmapURI);
ImageBrush_ProfilePicture.ImageSource = profilePictureBitmap;
}
This code doesn't have any extra check. It means the image 'ProfilePicture.jpg' have to be in a folder before running app. Code works well at first run but on the second run (press the button again and selecting new picture) cannot change output on screen even the source change in folder.

While creating BitmapImage set CreateOptions to IgnoreImageCache.
var profilePictureBitmap = new BitmapImage(profilePictureBitmapURI) {CreateOptions = BitmapCreateOptions.IgnoreImageCache};

Try to add the Load() method and see if that helps:
private async void AddProfilePicture_Click(object sender, RoutedEventArgs e)
{
FileOpenPicker profilePictureFilePicker = new FileOpenPicker();
profilePictureFilePicker.ViewMode = PickerViewMode.Thumbnail;
profilePictureFilePicker.SuggestedStartLocation = PickerLocationId.PicturesLibrary;
profilePictureFilePicker.FileTypeFilter.Add(".jpg");
StorageFile userSelectedProfilePicture = await profilePictureFilePicker.PickSingleFileAsync();
//MAKE SURE U HAVE THIS FILE (ProfilePicture.jpg) IN FOLDER ALREADY....
StorageFile destinationFileImage = await StorageFile.GetFileFromPathAsync(ApplicationData.Current.LocalFolder.Path + #"\" + "ProfilePicture.jpg");
await userSelectedProfilePicture.CopyAndReplaceAsync(destinationFileImage);
Uri profilePictureBitmapURI = new Uri(ApplicationData.Current.LocalFolder.Path + #"\" + "ProfilePicture.jpg");
BitmapImage profilePictureBitmap = new BitmapImage(profilePictureBitmapURI);
ImageBrush_ProfilePicture.ImageSource = profilePictureBitmap;
ImageBrush_ProfilePicture.Load()
}

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);