VNRequestCompletionHandler Delegate
Definition
Important
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A delegate that is called once for each feature detected in a VNRequest.
public delegate void VNRequestCompletionHandler(VNRequest request, NSError error);type VNRequestCompletionHandler = delegate of VNRequest * NSError -> unitParameters
- error
- NSError
If not null, an error that occurred during vision processing.
Remarks
Developers will typically downcast the <param name="request" /> to the expected subtype and retrieve relevant data from the downcast value:
var findFacesRequest = new VNDetectFaceRectanglesRequest((request, error) =>
{
if (error != null)
{
HandleError(error);
}
else
{
var frs = request as VNDetectFaceRectanglesRequest;
// Assert frs == findFacesRequest
var rs = frs.GetResults<VNFaceObservation>();
foreach (var fo in rs)
{ // ... etc ...