SizeChanged event on WPF control Event-args don't return proper Height value

Question

I developing an application in which I need to integrate scaling of the UI.Althrough it's something trivial to do, I experience some problems. My UI isn't particulary clean and well formated to begin with(the XAML).

I have a Grid which looks like this and acts as a wrapper for all other controls. It has the same height and width as the height & width of the window

<Grid x:Name="parentBox" Margin="10,10,2,0" Height="511" VerticalAlignment="Top">

Then I got a lot of other nested Grid's inside this grid and some other controls.The number of all controls is ~200.

Then I register the SizeChanged event for the "parentBox" named control which I noted above, and I have the following recursive algorithm to scale the controls.

Registered Event -----

private void ParentSizeChanged(object sender, System.Windows.SizeChangedEventArgs e)
{
    if (e.PreviousSize.Width != 0 && e.PreviousSize.Height != 0)
    {
        double coefficientHeight = e.NewSize.Height / e.PreviousSize.Height;
        double coefficientWidth = e.NewSize.Width / e.PreviousSize.Width;
        Scale(Parent, coefficientWidth, coefficientHeight);
    }
}

Function to scale all children.

    private void Scale(Grid Parent, double coefficientW, double coefficientH)
    {
        if (Parent.Children.Count == 0)
        {
            return;
        }
        else
        {
            if (coefficientH > 0 && coefficientW > 0)
            {
                Parent.Width *= coefficientW;
                Parent.Height *= coefficientH;
                for (int y = 0; y < Parent.Children.Count; y++)
                {
                    var child = Parent.Children[y];
                    if (child is Grid)
                    {
                        var childG = child as Grid;
                        Scale(childG, coefficientW, coefficientH);
                    }
                    else
                    {
                        if (child is ElementRepresentation)
                        {
                            var element = child as ElementRepresentation;

                            element.Width *= coefficientW;
                            element.Height *= coefficientH;
                            if (element.Height < 25 || element.Width < 25)
                            {
                                if (!ElementNames.ContainsKey(int.Parse(element.elementNumber.Text)))
                                {
                                    ElementNames.Add(int.Parse(element.elementNumber.Text), element.ElementLongName.Text);
                                    element.ElementLongName.Text = String.Empty;
                                }
                            }
                            if (element.ElementLongName.Text == String.Empty) 
                            {
                                element.ElementLongName.Text = ElementNames[int.Parse(element.elementNumber.Text)];
                            }
                        }
                        else
                        {
                            if(child is Label)
                            {
                                var label = child as Label;
                                label.Width *= coefficientW;
                                label.Height *= coefficientH;
                            }
                        }
                    }
                }
            }
        }
    }

While I debug and I scale the height of the Window the "parentBox" control the SizeChanged event fires only when I scale the window from the width side and nothing occurs when I try to do change the height.I'm suspecting it's something to do with my control placements which are inside the nested inside "parentBox" grids.

I appreciate your time to read this question.Thanks.

You know that a Grid can have cells (i.e. rows and columns) that are automatically resized when the Grid itself is resized? — Clemens
@Clemens Thanks for that tip, but the problem that I have is different.It's not the resizing that is the issue it's that I can't get the proper value for the Height of the window(like the height didn't change but infact I'am changing it). — Christo S. Christov
I'm just telling you that because to me your code seems entirely redundant. — Clemens

VenkyDhana VenkyDhana · Accepted Answer · 2014-07-16T11:36:22

You have defined the fixed size for Grid(Height="511").

Size changed event won't be called when you set the fixed size. You didn't change the width. That's why event is triggered when you change the width.

You need to remove the Height. By default height and width will be applied from the parent.

Regards,
Dhanasekar

SizeChanged event on WPF control Event-args don't return proper Height value

1 Answers