FeatureLayer¶
Namespace: ThinkGeo.Core
This class represents a layer that is comprised of feature data.
public abstract class FeatureLayer : Layer
Inheritance Object → LayerBase → Layer → FeatureLayer
Remarks:
This abstract class is the basis for all feature-based layers in the system. Its methods and properties deal with feature data manipulation. Some of the classes that currently inherit from this are ShapeFileFeatureLayer, OracleFeatureLayer and so on.
When creating your own FeatureLayer, you need only to set a FeatureSource and create a useful constructor; the class will take care of the rest. There are no required abstract members. It may be helpful for you to add additional properties specific to your FeatureSource.
Properties¶
Projection¶
public Projection Projection { get; }
Property Value¶
EditTools¶
This property gets the EditTools that allow you to easily edit InternalFeatures in the Feature Layer.
public EditTools EditTools { get; protected set; }
Property Value¶
This property gets the EditTools that allow you to easily edit InternalFeatures in the
Feature Layer.
Remarks:
The EditTools are supplied as an easily accessible wrapper for the editing methods of the FeatureSource.
FeatureIdsToExclude¶
A collection of strings representing record id of features not to get in the Layer.
public Collection<string> FeatureIdsToExclude { get; }
Property Value¶
Remarks:
This string collection is a handy place to specify what records not to get from the source. Suppose you have a shape file of roads and you want to hide the roads within a particular rectangle, simply execute GetFeaturesInsideBoundingBox() and add the id of the return features to the collection and forget about them. Since you can set this by Layer it makes is easy to determine what to and what not to.
QueryTools¶
This property gets the QueryTools that allow you to easily query Features from the Feature Layer.
public QueryTools QueryTools { get; protected set; }
Property Value¶
This property gets the QueryTools that allow you to easily query Features from the
Feature Layer.
Remarks:
This property gets the QueryTools that allow you to easily query Features from the Feature Layer. The QueryTools are supplied as an easily accessible wrapper for the query methods of the FeatureSource.
MaxRecordsToDraw¶
public int MaxRecordsToDraw { get; set; }
Property Value¶
FeatureSource¶
This property gets the FeatureSource for the FeatureLayer.
public FeatureSource FeatureSource { get; set; }
Property Value¶
FeatureSource
This property gets the FeatureSource for the FeatureLayer.
Remarks:
The FeatureSource is the provider of data to the FeatureLayer. There are different FeatureSource classes to match the various ways that feature data is stored. It is important that, when you inherit from the FeatureLayer, in the constructor you set the FeatureSource you want to use.
DrawingQuality¶
This property gets and sets the general drawing quality for the FeatureLayer's view.
public DrawingQuality DrawingQuality { get; set; }
Property Value¶
This property gets the general drawing quality for the FeatureLayer's
view.
Remarks:
The DrawingQuality enumeration allows you to control, in a macro sense, the drawing quality that will be used in the GeoCanvas. Each GeoCanvas, which is responsible for drawing of the features, may have its own specialized drawing quality properties. What the DrawingQuality enumeration does is define some general guidelines for each GeoCanvas. For example, if you set the DrawingQuality to HighSpeed, then inside of the PlatformGeoCanvas there is a profile for HighSpeed. This profile sets specific properties, such as the smoothing mode and composing drawing mode of the PlatformGeoCanvas. As each GeoCanvas may have different drawing quality properties, this offers a general way to control drawing quality and speed.
If you need complete control over how a specific GeoCanvas will draw, then you can set the DrawingQuality to Custom. This will tell the specific GeoCanvas to use the properties on its own object instead of one of the pre-defined profiles. If one of the profiles -- such as HighSpeed or HighQuality -- is set, then the specific GeoCanvas ignores its own properties for drawing quality.
ZoomLevelSet¶
This property gets and sets the ZoomLevelSet, which contains the specific zoom levels for the FeatureLayer.
public ZoomLevelSet ZoomLevelSet { get; set; }
Property Value¶
This property gets the ZoomLevelSet, which contains the specific zoom levels for
the FeatureLayer.
Remarks:
The ZoomLevelSet is a class that contains all of the ZoomLevels for the FeatureLayer. Each ZoomLevel contains the styles that are used to determine how to draw the InternalFeatures.
DrawingMarginInPixel¶
public float DrawingMarginInPixel { get; set; }
Property Value¶
Attribution¶
public string Attribution { get; set; }
Property Value¶
RequestDrawingInterval¶
public TimeSpan RequestDrawingInterval { get; set; }
Property Value¶
Name¶
This property gets and sets the name for the layer.
public string Name { get; set; }
Property Value¶
Remarks:
The name is user defined. It is useful to set, as it may be used for higher level components such as legends, etc.
IsOpen¶
This property returns true if the Layer is open and false if it is not.
public bool IsOpen { get; }
Property Value¶
Remarks:
This method is the concrete wrapper for the abstract method IsOpenCore. Various methods on the Layer require that it be in an open state. If one of those methods is called when the state is not open, then the method will throw an exception. To enter the open state, you must call the Layer Open method. The method will raise an exception if the current Layer is already open.
As this is a concrete public method that wraps a Core method, we reserve the right to add events and other logic to pre- or post-process data returned by the Core version of the method. In this way, we leave our framework open on our end, but also allow you the developer to extend our logic to suit your needs. If you have questions about this, please contact our support team as we would be happy to work with you on extending our framework.
IsVisible¶
This property gets and set the visible state of the layer.
public bool IsVisible { get; set; }
Property Value¶
Remarks:
If this property is set to false, the layer will not draw. We ensure this in the Draw method. This is useful for legends and other controls that control the visibility of layers.
DrawingTime¶
This property gets the last drawing time for the layer.
public TimeSpan DrawingTime { get; protected set; }
Property Value¶
Remarks:
We track the drawing time for the layer and report it back in this method. This is useful for determining the speed of various layers.
DrawingExceptionMode¶
public DrawingExceptionMode DrawingExceptionMode { get; set; }
Property Value¶
Background¶
Gets and sets the background of the layer.
public GeoColor Background { get; set; }
Property Value¶
Transparency¶
This property gets and sets the amount of transparency to apply to the image.
public float Transparency { get; set; }
Property Value¶
Single
This property gets the amount of transparency to apply to the image.
Remarks:
None
BlueTranslation¶
This property gets and sets the amount of blue to apply to the image.
public float BlueTranslation { get; set; }
Property Value¶
Single
This property gets the amount of blue to apply to the image.
Remarks:
None
RedTranslation¶
This property gets and sets the amount of red to apply to the image.
public float RedTranslation { get; set; }
Property Value¶
Single
This property gets the amount of red to apply to the image.
Remarks:
None
GreenTranslation¶
This property gets and sets the amount of green to apply to the image.
public float GreenTranslation { get; set; }
Property Value¶
Single
This property gets the amount of green to apply to the image.
Remarks:
None
KeyColors¶
Gets a value represents a collection of key colors. If SupportKeyColor property is false, it will throw exception when you use KeyColors.
public Collection<GeoColor> KeyColors { get; }
Property Value¶
Remarks:
It will make these colors transparent when draw image.
IsNegative¶
This property gets and sets whether the image should be converted to negative (inverse colors).
public bool IsNegative { get; set; }
Property Value¶
Boolean
This property gets and sets whether the image should be converted to negative (inverse colors).
Remarks:
None
IsGrayscale¶
This property gets and sets if the image should be converted to grayscale.
public bool IsGrayscale { get; set; }
Property Value¶
This property gets and sets if the image should be converted to grayscale.
Remarks:
None
HasBoundingBox¶
This property indicates whether a Layer has a BoundingBox or not. If it has no BoundingBox, it will throw an exception when you call the GetBoundingBox() and GetFullExtent() APIs.
public bool HasBoundingBox { get; }
Property Value¶
Remarks:
The default value is false.
ThreadSafe¶
public ThreadSafetyLevel ThreadSafe { get; set; }
Property Value¶
ColorMappings¶
ColorMapping
public Dictionary<GeoColor, GeoColor> ColorMappings { get; }
Property Value¶
Dictionary<GeoColor, GeoColor>
WrappingMode¶
public WrappingMode WrappingMode { get; set; }
Property Value¶
WrappingExtent¶
public RectangleShape WrappingExtent { get; set; }
Property Value¶
Methods¶
OnDrawingFeatures(DrawingFeaturesEventArgs)¶
This method raises the DrawingFeatures event.
protected void OnDrawingFeatures(DrawingFeaturesEventArgs e)
Parameters¶
e DrawingFeaturesEventArgs
This parameter represents the event arguments for the event.
Remarks:
You can call this method from a derived class to enable it to raise the event. This may be useful if you plan to extend the FeatureLayer and you need access to the event. This event is meant to allow you to add or remove the features to be drawn.
OnDrawingWrappingFeatures(DrawingWrappingFeaturesFeatureLayerEventArgs)¶
protected void OnDrawingWrappingFeatures(DrawingWrappingFeaturesFeatureLayerEventArgs e)
Parameters¶
e DrawingWrappingFeaturesFeatureLayerEventArgs
DrawCore(GeoCanvas, Collection<SimpleCandidate>)¶
This method will draw the FeatureLayer source based on the parameters provided.
protected void DrawCore(GeoCanvas canvas, Collection<SimpleCandidate> labelsInAllLayers)
Parameters¶
canvas GeoCanvas
This parameter is the GeoCanvas used to Draw the layer.
labelsInAllLayers Collection<SimpleCandidate>
This parameter is not used for ImageLayers.
Exceptions¶
InvalidOperationException
In the event you attempt to call this method on a FeatureLayer is not opened, it will throw an InvalidOperationException.
ArgumentNullException
If you pass a null as the labeledInLayers, we will throw an ArgumentNullException.
ArgumentNullException
If you pass a null as the worldExtent, we will throw an ArgumentNullException.
ArgumentNullException
If you pass a null as the image, we will throw an ArgumentNullException.
Remarks:
The DrawCore will be called when the layer is being drawn. It will check if the InternalFeatures are within the extent and whether it is within a defined zoom level. If these parameters are met, then it will apply the styles of the proper zoom level to the InternalFeatures for drawing. Lastly, it will draw InternalFeatures on the NativeImage or native image passed in to the method.
IsDrawingNeededCore(Double)¶
protected bool IsDrawingNeededCore(double currentScale)
Parameters¶
currentScale Double
Returns¶
SetupTools()¶
This method sets up the EditTools and QueryTools objects.
protected void SetupTools()
Remarks:
This method is the concrete wrapper for the abstract method SetupToolsCore. The SetupTools method allows you to create the QueryTool, EditTools and other tools you may need on your object. We created this method so that if you want to extend one of the tool classes, you can override the SetupToolsCore and create any class you want.
As this is a concrete public method that wraps a Core method, we reserve the right to add events and other logic to pre- or post-process data returned by the Core version of the method. In this way, we leave our framework open on our end, but also allow you the developer to extend our logic to suit your needs. If you have questions about this, please contact our support team as we would be happy to work with you on extending our framework.
SetupToolsCore()¶
This method sets up the EditTools and QueryTools objects.
protected void SetupToolsCore()
Remarks:
This method is the concrete wrapper for the abstract method SetupTools. The SetupTools method allows you to create the QueryTool, EditTools and other tools you may need on your object. We created this method so that if you want to extend one of the tool classes, you can override the SetupToolsCore and create any class you want.
OpenCore()¶
This method opens the FeatureLayer so that it is initialized and ready to use.
protected void OpenCore()
Exceptions¶
InvalidOperationException
In the event you attempt to call this method on a FeatureLayer which has already been opened, it will throw an InvalidOperationException.
Remarks:
This abstract method is called from the concrete public method Open. The Open method plays an important role, as it is responsible for initializing the FeatureLayer. Most methods on the FeatureLayer will throw an exception if the state of the FeatureLayer is not opened. When the map draws each FeatureLayer, it will open the layer as one of its first steps, then after it is finished drawing with that FeatureLayer it will close it. In this way we are sure to release all resources used by the FeatureLayer.
CloseCore()¶
This method closes the FeatureSource and releases any resources it was using.
protected void CloseCore()
Remarks:
This protected virtual method is called from the concrete public method Close. The close method plays an important role in the life cycle of the FeatureLayer. It may be called after drawing to release any memory and other resources that were allocated since the Open method was called.
If you override this method, it is recommended that you take the following things into account: This method may be called multiple times, so we suggest you write the method so that that a call to a closed FeatureLayer is ignored and does not generate an error. We also suggest that in the Close you free all resources that have been opened. Remember that the object will not be destroyed, but will be re-opened possibly in the near future.
GetBoundingBoxCore()¶
This method returns the bounding box of the FeatureLayer.
protected RectangleShape GetBoundingBoxCore()
Returns¶
RectangleShape
This method returns the bounding box of the FeatureLayer.
Exceptions¶
InvalidOperationException
In the event you attempt to call this method on a FeatureLayer which has not been opened, it will throw an InvalidOperationException.
Remarks:
This method is called from the concrete public method GetBoundingBox. It returns the bounding box of the FeatureLayer.
GetWrappingFeaturesForDrawing(RectangleShape, IEnumerable<String>, RectangleShape)¶
protected Collection<Feature> GetWrappingFeaturesForDrawing(RectangleShape drawingExtent, IEnumerable<string> returningColumnNames, RectangleShape wrappingExtent)
Parameters¶
drawingExtent RectangleShape
returningColumnNames IEnumerable<String>
wrappingExtent RectangleShape
Returns¶
GetCeiling(Double)¶
public double GetCeiling(double d)
Parameters¶
d Double
Returns¶
Events¶
DrawingFeatures¶
This event is raised when features are about to be drawn in the layer.
public event EventHandler<DrawingFeaturesEventArgs> DrawingFeatures;
Remarks:
This event is raised when features are about to be drawn in the layer. In the event arguments, there is a collection of features to be drawn. You can easily add or remove items from this collection so that extra items will draw or not draw.
DrawingWrappingFeatures¶
public event EventHandler<DrawingWrappingFeaturesFeatureLayerEventArgs> DrawingWrappingFeatures;
DrawingAttribution¶
public event EventHandler<DrawingAttributionLayerEventArgs> DrawingAttribution;
DrawnAttribution¶
public event EventHandler<DrawnAttributionLayerEventArgs> DrawnAttribution;
DrawingProgressChanged¶
public event EventHandler<DrawingProgressChangedEventArgs> DrawingProgressChanged;
RequestedDrawing¶
public event EventHandler<RequestedDrawingLayerEventArgs> RequestedDrawing;
RequestingDrawing¶
public event EventHandler<RequestingDrawingLayerEventArgs> RequestingDrawing;
DrawingException¶
public event EventHandler<DrawingExceptionLayerEventArgs> DrawingException;
DrawnException¶
public event EventHandler<DrawnExceptionLayerEventArgs> DrawnException;