/// <summary>
/// Updates the <see cref="MeasurableSubLayers"/> property based on the state of the sub-layers within
/// the current <see cref="MeasureLayer"/>. Will also update <see cref="MeasureSubLayer"/> if the
/// current one is in an unmeasurable state.
/// </summary>
private void UpdateMeasurableSubLayers()
{
// Dynamic map service layer containing sub-layers
ArcGISDynamicMapServiceLayer parentLayer = (ArcGISDynamicMapServiceLayer)MeasureLayer;
// index of the current measure sub-layer among the map service's sub-layers
int indexInMapService = parentLayer.Layers.IndexOf(MeasureSubLayer);
// index of the measure sub-layer among the set of measurable sub-layers
int indexInMeasurableLayers = MeasurableSubLayers.IndexOf(MeasureSubLayer);
// index to insert newly measurable sub-layers
int insertIndex = indexInMeasurableLayers + 1;
// tracks whether the current measure sub-layer has become unmeasurable
bool needsMeasureLayerUpdate = !MeasureSubLayer.IsMeasurable(parentLayer, Map);
// Iterate through the sub-layers in the parent map service that are after
// the current measure sub-layer
for (int i = indexInMapService + 1; i < parentLayer.Layers.Length; i++)
{
// Get the sub-layer at the current loop index
LayerInfo subLayer = parentLayer.Layers[i];
// Get whether the loop sub-layer is measurable and is already a member
// of the measurable sub-layers collection
bool isMeasurable = subLayer.IsMeasurable(parentLayer, Map);
bool isInCollection = MeasurableSubLayers.Contains(subLayer);
if (isMeasurable && !isInCollection) // sub-layer is measurable but not in
{ // collection, so it needs to be added.
MeasurableSubLayers.Insert(insertIndex, subLayer);
if (needsMeasureLayerUpdate) // check whether a new measure sub-layer needs to be selected
{
// Update the measure sub-layer and reset the update flag
MeasureSubLayer = subLayer;
needsMeasureLayerUpdate = false;
}
insertIndex++; // Increment the insertion index so the next sub-layer is inserted
// after this one
}
else if (!isMeasurable && isInCollection) // sub-layer in collection has become
{ // unmeasurable, so it needs to be removed
MeasurableSubLayers.Remove(subLayer);
}
else if (isMeasurable && isInCollection) // sub-layer is measurable and already in
{ // collection.
if (needsMeasureLayerUpdate)
{
MeasureSubLayer = subLayer; // Update the sub-layer if necessary and
needsMeasureLayerUpdate = false; // reset the update flag.
}
insertIndex++; // Increment insertion index so the next one
} // gets inserted after this one.
}
insertIndex = indexInMeasurableLayers;
// Iterate through the sub-layers in the parent map service that are before the current
// measure sub-layer, looping through them in reverse order
for (int i = indexInMapService - 1; i > -1; i--)
{
// Get the sub-layer at the current loop index
LayerInfo subLayer = parentLayer.Layers[i];
// Get whether the loop sub-layer is measurable and is already a member
// of the measurable sub-layers collection
bool isMeasurable = subLayer.IsMeasurable(parentLayer, Map);
bool isInCollection = MeasurableSubLayers.Contains(subLayer);
if (isMeasurable && !isInCollection) // sub-layer is measurable but not in
{ // collection, so it needs to be added.
MeasurableSubLayers.Insert(insertIndex, subLayer);
if (needsMeasureLayerUpdate) // check whether a new measure sub-layer needs to be selected
{
// Update the measure sub-layer and reset the update flag
MeasureSubLayer = subLayer;
needsMeasureLayerUpdate = false;
}
insertIndex--; // Decrement the insertion index so the next sub-layer is inserted
// before this one
}
else if (!isMeasurable && isInCollection) // sub-layer in collection has become
{ // unmeasurable, so it needs to be removed
MeasurableSubLayers.Remove(subLayer);
}
else if (isMeasurable && isInCollection) // sub-layer is measurable and already in
{ // collection.
if (needsMeasureLayerUpdate)
{
MeasureSubLayer = subLayer; // Update the sub-layer if necessary and
needsMeasureLayerUpdate = false; // reset the update flag.
}
insertIndex--; // Decrement insertion index so the next one
} // gets inserted before this one.
}
// Check whether original measure sub-layer needs to be removed
if (!parentLayer.Layers[indexInMapService].IsMeasurable(parentLayer, Map))
{
MeasurableSubLayers.Remove(parentLayer.Layers[indexInMapService]);
}
// If there are no more measurable sub-layers in the current measure layer, update
// the list of measurable layers.
if (MeasurableSubLayers.Count == 0)
{
UpdateMeasurableLayers();
}
}
