TdxAzureMapGeocodeProviderOnResponse Type

The procedural type for Azure Maps Geocode server response events.

Declaration

TdxAzureMapGeocodeProviderOnResponse = procedure(ASender: TdxMapControlAzureMapGeocodeProvider; AResponse: TdxAzureMapGeocodeRequestResponse; var ADestroyResponse: Boolean) of object;

Parameters

Name	Type	Description
ASender	TdxMapControlAzureMapGeocodeProvider	Provides access to the Azure Maps Geocode information component that raised the server response event.
AResponse	TdxAzureMapGeocodeRequestResponse	Provides access to a container populated with information returned by a server.
ADestroyResponse	Boolean	Specifies if the response event handler automatically destroys the information container accessible through the AResponse parameter. The event handler creates a new server response information container every time the event occurs. True Default. The AResponse container is destroyed automatically once the application exits the current event handler. You do not need to manage the response information container manually. False Use this option if you need to use the returned information container outside the server response event handler. Important Call the Free procedure (in Delphi) or use the delete keyword (in C++Builder) to destroy TdxAzureMapGeocodeRequestResponse class instances manually if you set the ADestroyResponse parameter to False. Otherwise, memory leaks will occur.

Remarks

Response events allow you to receive and process a server response after an asynchronous query.

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);
    }
  }
}

Direct TdxAzureMapGeocodeProviderOnResponse Type Reference

The TdxMapControlAzureMapGeocodeProvider.OnResponse event references the TdxAzureMapGeocodeProviderOnResponse procedural type.