无法在代码后面更改图像源

Question

I am trying to change Image.Source in code behind. When button clicked, Image.Source is modified in code behind and it supposed to display an image in windows. Unfortunately, it seems not working. Can anyone give me an idea what the problem is? Thank you.

Here are my codes:

XML :

`<Grid Margin="0,0,-234,0">
        <Image Source="{Binding SourceName, Mode=TwoWay}" 
        Height="100" Width="100" Margin="201,69,661,151"/>
        <Button Margin="201,215,644,39" Click="Button_Click">show image</Button>
 </Grid>`

C# part:

 private void Button_Click(object sender, RoutedEventArgs e)
    {
        Uri uri = new Uri(@"C:\localFTP\thisImage.jpg", UriKind.Absolute);

        BitmapImage i = new BitmapImage();
        i.BeginInit();
        i.UriSource = uri;
        i.EndInit();


        SourceName = i;
    }


    private ImageSource _sourceName;

    public ImageSource SourceName
    {
        get
        {
            return _sourceName;
        }
        set
        {
            _sourceName = value;
            OnPropertyChanged("SourceName");
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler handler = PropertyChanged;

        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }

Answer 1

You don't seem to have the source of the binding set anywhere.

So either you set your MainWindow's DataContext, eg in the constructor like

public MainWindow()
{
    InitializeComponent();   
    DataContext = this;
}

or you specify the binding source explicitly, eg by setting its RelativeSource:

<Image Source="{Binding SourceName,
                RelativeSource={RelativeSource AncestorType=Window}}"/>

---

As a note, SourceName seems to be a strange name for a property of type ImageSource. It should better be named Source or ImageSource .

It may also be worth to note that creating a BitmapImage actually requires less code than what you've shown in your question:

private void Button_Click(object sender, RoutedEventArgs e)
{
    var uri = new Uri(@"C:\localFTP\thisImage.jpg");
    SourceName = new BitmapImage(uri);
}