TdxMapControlAzureMapRouteProvider.OnResponse Event
Allows you to accept and process responses from an Azure Maps server.
#Declaration
property OnResponse: TdxAzureMapRouteProviderOnResponse read; write;
#Remarks
Handle the OnResponse
event to receive and process responses from an Azure Maps server after an ExecuteAsync procedure call.
#Event Occurrence
The OnResponse
event occurs every time an Azure Maps server sends a response after an ExecuteAsync procedure call.
#Event Parameters
The following parameters are available within an OnResponse
event handler:
ASender
- Provides access to the TdxMapControlAzureMapRouteProvider component that raised the server response event.
AResponse
- Provides access to a container populated within information returned by a server.
ADestroyResponse
Specifies if the
OnResponse
event handler automatically destroys the information container accessible through theAResponse
parameter.If this parameter value is
True
, the container is destroyed once the application exits the currentOnResponse
event handler. Otherwise, you need to release the container manually.
Refer to the TdxAzureMapRouteProviderOnResponse procedural type for detailed information on all available options.
#Code Example: Build a Map Route Asynchronously
The code example in this section demonstrates a procedure that sends a query to an Azure Maps Route server and an OnResponse
event handler that receives and processes the server response. The event handler uses an existing map item layer to draw a route between two specified points on a map if the query is successful.
uses
dxAzureMapInformationProviders, // Declares TdxMapControlAzureMapRouteProvider
dxMessageDialog, // Declares the dxMessageDlg global function
dxCoreGraphics; // Declares TdxAlphaColors
// ...
procedure TMyForm.SendRouteQuery(ARouteStart, ARouteEnd: TdxMapControlGeoPoint);
var
AQueryParams: IdxAzureMapRouteQueryParams;
ARouteWaypoints: TdxMapControlGeoPoints;
begin
AQueryParams := dxMapControl1AzureMapRouteProvider1.CreateQueryParams;
SetLength(ARouteWaypoints, 2);
ARouteWaypoints[0] := ARouteStart;
ARouteWaypoints[1] := ARouteEnd;
AQueryParams.WayPoints := ARouteWaypoints;
AQueryParams.TravelMode := TdxAzureMapRouteTravelMode.Car;
AQueryParams.MaxAlternatives := 1;
dxMapControl1AzureMapRouteProvider1.ExecuteAsync(AQueryParams);
end;
procedure TMyForm.dxMapControl1AzureMapRouteProvider1Response(
ASender: TdxMapControlAzureMapRouteProvider;
AResponse: TdxAzureMapRouteRequestResponse; var ADestroyResponse: Boolean);
var
APolyline: TdxMapPolyline;
ARoute: TdxAzureMapRouteItem;
I, J: Integer;
begin
dxMapControl1.BeginUpdate; // Initiates the following batch change
try
if AResponse <> nil then
begin
if AResponse.IsSuccess then // Draws a route if a valid server response is received
begin
APolyline := dxMapControl1ItemLayer1.AddItem(TdxMapPolyline) as TdxMapPolyline;
ARoute := AResponse.Routes.Items[0]; // Selects the first returned route
for I := 0 to ARoute.Legs.Count - 1 do
for J := 0 to ARoute.Legs.Items[I].Points.Count - 1 do
APolyline.GeoPoints.Add.GeoPoint := ARoute.Legs.Items[I].Points.Items[J];
APolyline.Style.BorderWidth := 4;
APolyline.Style.BorderColor := TdxAlphaColors.DarkBlue;
end
else if Assigned(AResponse.ErrorInfo) then
dxMessageDlg(AResponse.ErrorInfo.Message, TMsgDlgType.mtError, [mbOK], 0);
end;
finally
dxMapControl1.EndUpdate; // Calls EndUpdate regardless of the batch operation's success
end;
end;