// https://docs.microsoft.com/en-us/dotnet/framework/wpf/advanced/walkthrough-enabling-drag-and-drop-on-a-user-control
private void canvas_DragOver(object sender, DragEventArgs e)
{
if (e.Data.GetDataPresent(MyRockShape.RockViewModelDataFormatName))
{
//Debug.WriteLine("canvas_DragOver");
bool isAllowedDragMove = false;
// Canvas inherits Panel
Panel _canvas = sender as Panel;
RockViewModel selectedRock = rocksOnWallViewModel.SelectedRock;
if (_canvas != null && selectedRock != null)
{
Point mousePt = e.GetPosition(cameraIMG);
// check rock overlaps
if (rocksOnWallViewModel.IsOverlapWithRocksOnWallOtherThanSelectedRock(
mousePt, selectedRock.SizeOnCanvas)
== false)
{
CameraSpacePoint csp = jcWall.GetCamSpacePointFromMousePoint(mousePt, _mode);
if (!csp.Equals(default(CameraSpacePoint)))
{
// note:
// use RocksOnWallViewModel.MoveSelectedRock()
// instead of RockViewModel.MoveBoulder()
// because RocksOnWallViewModel.MoveSelectedRock()
// will set the selected rock indicator as well
isAllowedDragMove = rocksOnWallViewModel.MoveSelectedRock(csp);
}
}
}
// These Effects values are used in the drag source's
// GiveFeedback event handler to determine which cursor to display.
if (isAllowedDragMove)
{
e.Effects = supportedDragDropEffects;
}
else
{
e.Effects = DragDropEffects.None;
}
}
}
private void boulderSizeSlider_ValueChanged(object sender, RoutedPropertyChangedEventArgs <double> e)
{
Slider boulderSizeSlider = sender as Slider;
if (boulderSizeSlider.Value == 0)
{
UiHelper.NotifyUser("Zero size is not allowed.");
boulderSizeSlider.Value = boulderSizeSlider.Minimum + boulderSizeSlider.TickFrequency;
}
if (rocksOnWallViewModel != null && rocksOnWallViewModel.SelectedRock != null)
{
double newBoulderWidthOnCanvas = ConvertSliderValueToSizeOnCanvas(boulderWidthSlider.Value);
double newBoulderHeightOnCanvas = ConvertSliderValueToSizeOnCanvas(boulderHeightSlider.Value);
// check rock overlaps
if (rocksOnWallViewModel.IsOverlapWithRocksOnWallOtherThanSelectedRock(
rocksOnWallViewModel.SelectedRock.BCanvasPoint,
newBoulderWidthOnCanvas, newBoulderHeightOnCanvas)
== false)
{
string boulderSizeSliderName = boulderSizeSlider.Name;
switch (boulderSizeSliderName)
{
case "boulderHeightSlider":
rocksOnWallViewModel.ChangeHeightOfSelectedRock(newBoulderHeightOnCanvas);
break;
case "boulderWidthSlider":
default:
rocksOnWallViewModel.ChangeWidthOfSelectedRock(newBoulderWidthOnCanvas);
break;
}
}
else
{
UiHelper.NotifyUser(RockOverlapsWarningMsg);
// restore original value
boulderSizeSlider.Value -= boulderSizeSlider.TickFrequency;
}
}
}