CODEWITHSUNDEEP
c#wpfimagemvvmviewmodel
Ankit
Ankit

Reputation: 672

Save a region of screen in WPF app following MVVM

I have a WPF application following the MVVM architecture.

On one of the screens is a chart which needs to be saved as an image file on Save button click.

I can save the chart using the below code in code behind:

        Rectangle rect = new Rectangle(0, 0, 100, 100);
        Bitmap bmp = new Bitmap(rect.Width, rect.Height, PixelFormat.Format32bppArgb);
        Graphics g = Graphics.FromImage(bmp);
        g.CopyFromScreen(rect.Left, rect.Top, 0, 0, bmp.Size, CopyPixelOperation.SourceCopy);
        bmp.Save(fileName, ImageFormat.Jpeg);

But I need to be able to do this in my ViewModel.

For this purpose, I pass the ActualHeight & ActualWidth as the command parameters for the Click command of the button in below manner:

<Button Content="Save" Command="{Binding MyViewModel.SaveCommand">
    <Button.CommandParameter>
        <MultiBinding Converter="{StaticResource DimensionConverter}">
             <Binding Path="ActualWidth" ElementName="MyChart"/>
             <Binding Path="ActualHeight" ElementName="MyChart"/>
        </MultiBinding>
    </Button.CommandParameter>
</Button>

In my converter:

public class DimensionConverter : IMultiValueConverter
{
    public object Convert(object[] values, ...)
    {
        return values.Clone();
    }

    ...
}

Then, in command execution logic:

public void OnExecute(object parameter)
{
    var values = (object[])parameter;
    var width = (double)values[0];
    var height = (double)values[1];
    ...
}

But, I also need to be able to pass the co-ordinates of the Chart control wrt Origin. This can be done using PointToScreen method. But how can I pass them to the view model keeping in mind MVVM?

Or is there any other way that I can capture a region of a screen & save as image in MVVM architecture?

Upvotes: 3

Views: 797

Answers (0)

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