WPF DataGrid Zoom to mouse position - wpf

Question

I have a DataGrid that LayoutTransform is Binded to a Slider like that:
<DataGrid.LayoutTransform>
<ScaleTransform
ScaleX="{Binding ElementName=MySlider, Path=Value}"
ScaleY="{Binding ElementName=MySlider, Path=Value}" />
</DataGrid.LayoutTransform>
</DataGrid>
<Slider x:Name="MySlider"
Minimum="0.3"
Maximum="2.0"
SmallChange="0.1"
LargeChange="0.1"
Value="1.0"
IsSnapToTickEnabled="True"
TickFrequency="0.1"
TickPlacement="TopLeft"
VerticalAlignment="Bottom"
HorizontalAlignment="Right"
Width="200"
Margin="0,0,61,0" />
<TextBlock Name="Lstate"
Text="{Binding ElementName=MySlider, Path=Value, StringFormat={}{0:P0}}"
VerticalAlignment="Bottom"
HorizontalAlignment="Right"
Width="50" Height="20"
Margin="0,0,0,1" />
Now, in the Code I have the PreviewMouseWheel event with the following Code:
bool handle = (Keyboard.Modifiers & ModifierKeys.Control) > 0;
if (!handle)
return;
double value;
if (e.Delta > 0)
value = 0.1;
else
value = -0.1;
MySlider.Value += value;
And my question is: How to scroll to the actual Mouse Position like AutoCad or some other programs?
Thanks
Sorry for my bad english...

Answer 1

I have a very very good solution now:
VirtualizingStackPanel.IsVirtualizing="True"
VirtualizingStackPanel.VirtualizationMode="Standard"
EnableColumnVirtualization="False"
EnableRowVirtualization="True"
ScrollViewer.CanContentScroll="True"
private void Data_OnPreviewMouseWheel(object sender, MouseWheelEventArgs e)
{
// Scroll to Zoom
if (Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl))
{
// Prevent scroll
e.Handled = true;
var scrollview = FindVisualChild<ScrollViewer>(Data);
if (scrollview != null)
{
// The "+20" are there to account for the scrollbars... i think. Not perfectly accurate.
var relativeMiddle = new Point((Data.ActualWidth + 20) / 2 + (Mouse.GetPosition(Data).X - Data.ActualWidth / 2), (Data.ActualHeight + 20) / 2 + (Mouse.GetPosition(Data).Y - Data.ActualHeight / 2));
var oldLocation = Data.LayoutTransform.Transform(Data.PointFromScreen(relativeMiddle));
// Zoom
MySlider.Value += (e.Delta > 0) ? MySlider.TickFrequency : -MySlider.TickFrequency;
// Scroll
var newLocation = Data.LayoutTransform.Transform(Data.PointFromScreen(relativeMiddle));
// Calculate offset
var shift = newLocation - oldLocation;
if (scrollview.CanContentScroll)
{
// Scroll to the offset (Item)
scrollview.ScrollToVerticalOffset(scrollview.VerticalOffset + shift.Y / scrollview.ViewportHeight);
}
else
{
// Device independent Pixels
scrollview.ScrollToVerticalOffset(scrollview.VerticalOffset + shift.Y);
}
// Device independent Pixels
scrollview.ScrollToHorizontalOffset(scrollview.HorizontalOffset + shift.X);
}
}
}
It zooms to the Mouse Position on the Datagrid with and without virtualization.