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TdxMapControlAzureMapRouteProvider.ExecuteAsync(IdxAzureMapRouteQueryParams) Method

Sends an asynchronous query to an Azure Maps Route server.

#Declaration

Delphi
procedure ExecuteAsync(const AParams: IdxAzureMapRouteQueryParams);

#Parameters

Name Type Description
AParams IdxAzureMapRouteQueryParams

Accepts a configured query parameters container.

Call the CreateQueryParams function to create a query parameters container.

#Remarks

Call the ExecuteAsync procedure to send an asynchronous query to an Azure Maps Route server. To cancel pending asynchronous queries, call the CancelRequests procedure.

#Receive Server Responses to Asynchronous Queries

Handle the OnResponse event to receive and process a server query after an ExecuteAsync procedure call.

#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;
See Also