Method IdentifyGraphicsOverlayAsync
IdentifyGraphicsOverlayAsync(GraphicsOverlay, Point, Double, Boolean)
Identifies the topmost graphic in the specified graphics overlay, at the given screen point.
Declaration
public async Task<IdentifyGraphicsOverlayResult> IdentifyGraphicsOverlayAsync(GraphicsOverlay graphicsOverlay, Point screenPoint, double tolerance, bool returnPopupsOnly)
Parameters
Type | Name | Description |
---|---|---|
GraphicsOverlay | graphicsOverlay | The graphics overlay in which to identify the graphic. |
System.Windows.Point | screenPoint | The screen coordinates to identify the graphic. |
System.Double | tolerance | A radius in device-independent pixels (DIP) that specifies how precise the identify operation should be. |
System.Boolean | returnPopupsOnly |
|
Returns
Type | Description |
---|---|
System.Threading.Tasks.Task<IdentifyGraphicsOverlayResult> | A task that represents the asynchronous identify operation on the specified graphics overlay. The value of the TResult parameter contains a read-only collection of Graphic |
Remarks
As locations from user gestures are not always accurate to the exact pixel, you can define a tolerance for the identify operation. The tolerance parameter sets the radius of a circle, centered at the specified coordinates, in device-independent pixels (DIP). If the tolerance value is 0, identify performs the test at the specified coordinates. If it is greater than 0, identify tests inside the circle. For touch displays a value of 22 is recommended to cover an average finger tap. The maximum allowed value is 100 DIPs.
The returnPopupsOnly
parameter controls which properties are populated in the IdentifyGraphicsOverlayResult
instance. If returnPopupsOnly
is true
, Popups is populated. If the
overlay does not have popups an error is returned. If returnPopupsOnly
is false
,
Graphics and Popups are populated,
if the overlay has popups.
Exceptions
Type | Condition |
---|---|
System.ArgumentNullException | graphicsOverlay |
Applies to
Platforms and versions
Target | Versions |
---|---|
.NET Windows | 100.13 - 200.5 |
.NET Framework | 100.0 - 200.5 |
IdentifyGraphicsOverlayAsync(GraphicsOverlay, Point, Double, Boolean, Int64)
Identifies a limited number of graphics in the specified graphics overlay, at the given screen point.
Declaration
public async Task<IdentifyGraphicsOverlayResult> IdentifyGraphicsOverlayAsync(GraphicsOverlay graphicsOverlay, Point screenPoint, double tolerance, bool returnPopupsOnly, long maximumResults)
Parameters
Type | Name | Description |
---|---|---|
GraphicsOverlay | graphicsOverlay | The graphics overlay in which to identify the graphics. |
System.Windows.Point | screenPoint | The screen coordinates to identify the graphics. |
System.Double | tolerance | A radius in device-independent pixels (DIP) that specifies how precise the identify operation should be. |
System.Boolean | returnPopupsOnly |
|
System.Int64 | maximumResults | The maximum number of graphics and/or popups returned in the IdentifyGraphicsOverlayResult. A value of -1 indicates unlimited results. |
Returns
Type | Description |
---|---|
System.Threading.Tasks.Task<IdentifyGraphicsOverlayResult> | A task that represents the asynchronous identify operation on the specified graphics overlay. The value of the TResult parameter contains a read-only collection of Graphic |
Remarks
As locations from user gestures are not always accurate to the exact pixel, you can define a tolerance for the identify operation. The tolerance parameter sets the radius of a circle, centered at the specified coordinates, in device-independent pixels (DIP). If the tolerance value is 0, identify performs the test at the specified coordinates. If it is greater than 0, identify tests inside the circle. For touch displays a value of 22 is recommended to cover an average finger tap. The maximum allowed value is 100 DIPs.
The returnPopupsOnly
parameter controls which properties are populated in the IdentifyGraphicsOverlayResult
instance. If true
, only Popups is populated. If the overlay does not
have popups an error is returned. If false
, both Graphics and
Popups are populated, if the overlay has popups.
Exceptions
Type | Condition |
---|---|
System.ArgumentNullException | graphicsOverlay |
Applies to
Platforms and versions
Target | Versions |
---|---|
.NET Windows | 100.13 - 200.5 |
.NET Framework | 100.0 - 200.5 |