// Logic that is called when a template is needed for a list view item.
protected override DataTemplate OnSelectTemplate(object item, BindableObject container)
{
DataTemplate selectedTemplate = null;
// Get the current list item being created. Return if the item is null.
DatumTransformationListBoxItem transformationItem = item as DatumTransformationListBoxItem;
if (item == null)
{
return(null);
}
// Read the IsMissingProjectionEngineFiles property to select the available or unavailable data template.
if (transformationItem.TransformationObject.IsMissingProjectionEngineFiles)
{
selectedTemplate = _unavailableTransformTemplate;
}
else if (!transformationItem.TransformationObject.IsMissingProjectionEngineFiles)
{
selectedTemplate = _availableTransformTemplate;
}
// See if this is the default transformation.
if (transformationItem.IsDefault)
{
selectedTemplate = _defaultTransformTemplate;
}
// Return the selected template.
return(selectedTemplate);
}
// Function to get suitable datum transformations for the specified input and output spatial references.
private void GetSuitableTransformations(SpatialReference inSpatialRef, SpatialReference outSpatialRef, bool considerExtent)
{
// Get suitable transformations. Use the current extent to evaluate suitability, if requested.
IReadOnlyList <DatumTransformation> transformations;
if (considerExtent)
{
Envelope currentExtent = MyMapView.GetCurrentViewpoint(ViewpointType.BoundingGeometry).TargetGeometry as Envelope;
transformations = TransformationCatalog.GetTransformationsBySuitability(inSpatialRef, outSpatialRef, currentExtent);
}
else
{
transformations = TransformationCatalog.GetTransformationsBySuitability(inSpatialRef, outSpatialRef);
}
// Get the default transformation for the specified input and output spatial reference.
DatumTransformation defaultTransform = TransformationCatalog.GetTransformation(inSpatialRef, outSpatialRef);
List <DatumTransformationListBoxItem> transformationItems = new List <DatumTransformationListBoxItem>();
// Wrap the transformations in a class that includes a boolean to indicate if it's the default transformation.
foreach (DatumTransformation transform in transformations)
{
DatumTransformationListBoxItem item = new DatumTransformationListBoxItem(transform)
{
IsDefault = (transform.Name == defaultTransform.Name)
};
transformationItems.Add(item);
}
// Set the transformation list property that the list box binds to.
SuitableTransformationsList = transformationItems;
}
private void TransformationsListBox_ItemSelected(object sender, SelectedItemChangedEventArgs e)
{
// Get the selected transform from the list box. Return if there isn't a selected item.
DatumTransformationListBoxItem selectedListBoxItem = TransformationsListBox.SelectedItem as DatumTransformationListBoxItem;
if (selectedListBoxItem == null)
{
return;
}
// Get the datum transformation object from the list box item.
DatumTransformation selectedTransform = selectedListBoxItem.TransformationObject;
try
{
// Project the original point using the selected transform.
MapPoint projectedPoint = (MapPoint)GeometryEngine.Project(_originalPoint, MyMapView.SpatialReference, selectedTransform);
// Update the projected graphic (if it already exists), create it otherwise.
if (_projectedPointGraphic != null)
{
_projectedPointGraphic.Geometry = projectedPoint;
}
else
{
// Create a symbol to represent the projected point (a cross to ensure both markers are visible).
SimpleMarkerSymbol projectedPointMarker = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Cross, Colors.Red, 15);
// Create the point graphic and add it to the overlay.
_projectedPointGraphic = new Graphic(projectedPoint, projectedPointMarker);
_pointsOverlay.Graphics.Add(_projectedPointGraphic);
}
MessagesTextBox.Text = "Projected point using transform: " + selectedTransform.Name;
}
catch (ArcGISRuntimeException ex)
{
// Exception if a transformation is missing grid files.
MessagesTextBox.Text = "Error using selected transformation: " + ex.Message;
// Remove the projected point graphic (if it exists).
if (_projectedPointGraphic != null && _pointsOverlay.Graphics.Contains(_projectedPointGraphic))
{
_pointsOverlay.Graphics.Remove(_projectedPointGraphic);
_projectedPointGraphic = null;
}
}
}