TdxMapControlAzureMapGeocodeProvider.OnResponse Event

Allows you to accept and process responses from an Azure Maps server.

Declaration

property OnResponse: TdxAzureMapGeocodeProviderOnResponse 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 TdxMapControlAzureMapGeocodeProvider component that raised the server response event.

AResponse

Provides access to a container populated with information returned by a server.

ADestroyResponse

Specifies if the OnResponse event handler automatically destroys the information container accessible through the AResponse parameter.

If this parameter value is True, the container is destroyed once the application exits the current OnResponse event handler. Otherwise, you need to release the container manually.

Refer to the TdxAzureMapGeocodeProviderOnResponse procedural type description for detailed information on all available options.

Code Example: Obtain Point Coordinates by Address Asynchronously

The code example in this section demonstrates a procedure that sends a query to an Azure Maps Geocode server and an OnResponse event handler that receives and processes the server response. The event handler uses an existing map layer to draw a pushpin at the obtained point coordinates if the query is successful.

Delphi

uses
  dxAzureMapInformationProviders,  // Declares TdxMapControlAzureMapGeocodeProvider
  dxMessageDialog;  // Declares the dxMessageDlg global function
// ...

procedure TMyForm.SendGeocodeQuery(const AAddress: string);
var
  AQueryParams: IdxAzureMapGeocodeQueryParams;
begin
  AQueryParams := dxMapControl1AzureMapGeocodeProvider1.CreateQueryParams;
  AQueryParams.Query := AAddress;
  dxMapControl1AzureMapGeocodeProvider1.ExecuteAsync(AQueryParams);
end;

procedure TMyForm.dxMapControl1AzureMapGeocodeProvider1Response(
  ASender: TdxMapControlAzureMapGeocodeProvider;
  AResponse: TdxAzureMapGeocodeRequestResponse; var ADestroyResponse: Boolean);
var
  APushpin: TdxMapPushpin;
begin
  if AResponse <> nil then
  begin
    if AResponse.IsSuccess then  // Creates a pushpin at the obtained position if the query is successful
    begin
      APushpin := dxMapControl1ItemLayer1.MapItems.Add(TdxMapPushpin) as TdxMapPushpin;
      APushpin.Location.GeoPoint.Longitude := AResponse.Features.First.Geometry.Coordinates[0];
      APushpin.Location.GeoPoint.Latitude := AResponse.Features.First.Geometry.Coordinates[1];
    end
    else if Assigned(AResponse.ErrorInfo) then
      dxMessageDlg(AResponse.ErrorInfo.Message, TMsgDlgType.mtError, [mbOK], 0);
  end;
end;

C++

#include "dxAzureMapInformationProviders.hpp"  // Declares TdxMapControlAzureMapGeocodeProvider
#include "dxMessageDialog.hpp"  // Declares the dxMessageDlg global function
// ...

void __fastcall TMyForm::SendGeocodeQuery(const UnicodeString &AAddress)
{
  _di_IdxAzureMapGeocodeQueryParams AQueryParams;
  AQueryParams = dxMapControl1AzureMapGeocodeProvider1->CreateQueryParams();
  AQueryParams->Query = AAddress;
  dxMapControl1AzureMapGeocodeProvider1->ExecuteAsync(AQueryParams);
}

void __fastcall TMyForm::dxMapControl1AzureMapGeocodeProvider1Response(
  TdxMapControlAzureMapGeocodeProvider *ASender,
  TdxAzureMapGeocodeRequestResponse *AResponse, bool &ADestroyResponse)
{
  TdxMapItem *AMapItem;
  TdxMapPushpin *APushpin;
  if(AResponse != nullptr)
  {
    if(AResponse->IsSuccess)  // Creates a pushpin at the obtained position if the query is successful
    {
      AMapItem = dxMapControl1ItemLayer1->MapItems->Add(__classid(TdxMapPushpin));
      APushpin = dynamic_cast<TdxMapPushpin*>(AMapItem);
      APushpin->Location->GeoPoint.Longitude = AResponse->Features->First()->Geometry->Coordinates[0];
      APushpin->Location->GeoPoint.Latitude = AResponse->Features->First()->Geometry->Coordinates[1];
    }
    else if(AResponse->ErrorInfo != nullptr)
    {
      dxMessageDlg(AResponse->ErrorInfo->Message, TMsgDlgType::mtError, TMsgDlgButtons() << mbOK, 0);
    }
  }
}