“Cannot convert string to ImageSource.” How can I do this?

问题

private void HeroMouseEnter(object sender, MouseEventArgs e)
    {
        ((Image)sender).Source = GetGlowingImage(((Image)sender).Name);            
    }

    public ImageSource GetGlowingImage(string name)
    {
        switch (name)
        {
            case "Andromeda":
                return "HeroGlowIcons/64px-Andromeda.gif";                
            default:
                return null;
        }
    }

I'm just trying to make an event to change the image according to where the mouse entered. But I cannot make this work.

Edit: I did this in Windows Forms and it work 100% like I want it to. How could I translate something like this in WPF?

void HeroMouseEnter(object sender, EventArgs e)
    {
        ((PictureBox)sender).Image = GetGlowingImage(((PictureBox)sender).Name);           
    }


    public Image GetGlowingImage(string name)
    {
        switch (name)
        {
            case "Andromeda":
                return Properties.Resources._64px_Andromedahero___copia;
            case "Engineer":
                return Properties.Resources._64px_Engineerhero___copia;
            default:
                return null;
        }
    }

回答1:

In your GetGlowingImage() method you need to generate a new ImageSource

This link might help: Setting WPF image source in code

Edit:

See the difference here is that in the WindowsForms code you have the Properties.Resources._64px_Andromedahero___copia is the name of an Image variable that contains the image data. In your WPF code the string "filename...." is not an image or image source it's just a string that represents the path to the file. You need to load the image file using that path.

I know it doesn't make sense because at design time you can specify a filename and it builds the ImageSource for you. In code you need to create the ImageSource (or derived object, ie: BitmapSource) and load the appropriate image into it.

Edit: Try this, untested (and check my link above):

    public ImageSource GetGlowingImage(string name)
    {
        string fileName = string.Empty;

        switch (name)
        {
            case "Andromeda":
                {
                    fileName = "HeroGlowIcons/64px-Andromeda.gif";
                    break;
                }
        }

        BitmapImage glowIcon = new BitmapImage();


        glowIcon.BeginInit();
        glowIcon.UriSource = new Uri("pack://application:,,,/ApplicationName;component/" + fileName);
        glowIcon.EndInit();

        return glowIcon;
    }

回答2:

Going by your edit, you are happy to have a static set of images in resources. If that's correct, you can do this:

<Application.Resources>
  <BitmapImage x:Key="andromeda64" UriSource="andromeda_64px.jpg" />
</Application.Resources>

then load it as:

public ImageSource GetGlowingImage(string name)
{
  switch (name)
  {
    case "Andromeda":
      return (ImageSource)FindResource("andromeda64");
    default:
      return null;
  }
}

FindResource requires you to be in code-behind for something in the visual tree (e.g. an event handler). If this isn't the case, or if you want to be able to load things that aren't in a resource dictionary, see Cory's answer. The advantage of using and reusing resources is that you don't need to create a BitmapImage each time you use it (though in this case the overhead cost of doing so will be insignificant).

回答3:

Something like:

BitmapImage myBitmapImage = new BitmapImage(new Uri("../../../../Images/folder.png", UriKind.Relative));
myBitmapImage.CacheOption = BitmapCacheOption.OnLoad;
Image.Source = myBitmapImage;

回答4:

You probably want to return a BitmapSource. This MSDN article has an example of how to create a BitmapSource from an image file.

回答5:

Consider using an EventTrigger to do this completely in XAML instead of messing with magic strings in the code behind.

This link would help

回答6:

for more if you intent to change the background of a Grid or other Panel that support System.Windows.Media.Brush with a click of a button

private void btnBackgroundImage_Click(object sender, RoutedEventArgs e)
{
    OpenFileDialog dlg = new OpenFileDialog();
    dlg.Filter = "Image Files (*.bmp;*.png;*.jpg;)|*.bmp;*.png;*.jpg";
    dlg.Multiselect = false;
    dlg.RestoreDirectory = true;

    if (dlg.ShowDialog() == true)
    {
        txtBackImageName.Text = dlg.FileName;
        _layoutRoot.Background = new System.Windows.Media.ImageBrush(GetImageSource(dlg.FileName));
    }
}


public ImageSource GetImageSource(string filename)
{
    string _fileName = filename;

    BitmapImage glowIcon = new BitmapImage();

    glowIcon.BeginInit();
    glowIcon.UriSource = new Uri(_fileName);
    glowIcon.EndInit();

    return glowIcon;
}

回答7:

var converter = new Xamarin.Forms.ImageSourceConverter();
var imgSource = (Xamarin.Forms.ImageSource) converter.ConvertFromInvariantString(item.Poster);

来源：https://stackoverflow.com/questions/1904956/cannot-convert-string-to-imagesource-how-can-i-do-this

标签

wpf

image

mouseevent