TdxMapControlAzureMapReverseGeocodeProvider Class
An Azure Maps Reverse Geocode information provider.
#Declaration
TdxMapControlAzureMapReverseGeocodeProvider = class(
TdxMapControlAzureMapInformationProvider
)
#Remarks
The TdxMapControlAzureMapReverseGeocodeProvider
component allows you to use Azure Maps Reverse Geocode servers to obtain information associated with a geographic point on a map (address, postcode, etc.) based on the point’s location on the map (latitude and longitude coordinates).
#Azure Maps Account
To use Microsoft Azure Maps® services, you need to create an Azure Maps account and obtain a key. Assign the account key to the AzureKey property to configure the information provider.
#Main API Members
The list below outlines key members of the TdxMapControlAzureMapReverseGeocodeProvider
class. These members allow you to access Azure Maps services and obtain information associated with a point on the map.
#Server-Related API Members
- AzureKey
- Required. Specifies the account key required to use the reverse geocode Azure provider.
- CancelRequests
- Cancels pending asynchronous queries to Azure Maps Reverse Geocode servers.
- CreateQueryParams
- Creates an information container required to send a query to an Azure Maps Reverse Geocode server.
- Execute | ExecuteAsync
- Send a query created by a CreateQueryParams function call.
- OnResponse
- Allows you to receive and process a server response after an asynchronous query.
#Collection-Related API Members
- Collection
- Provides access to the parent collection.
- DisplayName
- Specifies the information provider’s name displayed in the design-time collection editor dialog.
- Index
- Specifies the information provider’s index in the parent collection.
- ID
- Returns the component’s unique identifier.
#Code Examples
#Create and Configure Azure Maps Information Providers
The following code example implements a procedure that accepts an Azure Maps account key, and creates and configures all Azure Maps information provider components:
uses
dxAzureMapInformationProviders; // Declares all Azure Maps information provider classes
// ...
procedure TMyForm.CreateAzureMapsInformationProviders(const AAzureKey: string);
var
AProviders: TdxMapControlInformationProviders;
AProvider: TdxMapControlAzureMapInformationProvider;
I: Integer;
begin
AProviders := dxMapControl1.InformationProviders;
AProviders.BeginUpdate; // Initiates the following batch change
try
// Create all Azure Maps information providers
AProviders.Add(TdxMapControlAzureMapGeocodeProvider);
AProviders.Add(TdxMapControlAzureMapGeolocationProvider);
AProviders.Add(TdxMapControlAzureMapReverseGeocodeProvider);
AProviders.Add(TdxMapControlAzureMapRouteProvider);
for I := 0 to AProviders.Count - 1 do // Iterates through all created information providers
begin
AProvider := AProviders.Items[I] as TdxMapControlAzureMapInformationProvider;
AProvider.AzureKey := AAzureKey; // Assigns the same Azure Maps account key to all providers
end;
finally
AProviders.EndUpdate; // Calls EndUpdate regardless of the batch operation's success
end;
end;
#Obtain Map Point Address
The following code example implements a procedure that uses a configured information provider component to create a pushpin at the specified point on the map and assign the point’s address to the pushpin hint:
uses
dxAzureMapInformationProviders; // Declares TdxMapControlAzureMapReverseGeocodeProvider
// ...
procedure TMyForm.AddPushpin(AGeoPoint: TdxMapControlGeoPoint);
var
APushpin: TdxMapPushpin;
AParams: IdxAzureMapReverseGeocodeQueryParams;
AResponse: TdxAzureMapReverseGeocodeRequestResponse;
begin
// Creates a new pushpin on an existing map item layer
APushpin := dxMapControl1ItemLayer1.MapItems.Add(TdxMapPushpin) as TdxMapPushpin;
APushpin.Location.GeoPoint := AGeoPoint;
AParams := dxMapControl1AzureMapReverseGeocodeProvider1.CreateQueryParams;
AParams.Coordinates := APushpin.Location.GeoPoint;
// Uses a configured reverse geocode provider to send a query to an Azure Maps server
dxMapControl1AzureMapReverseGeocodeProvider1.Execute(AParams, AResponse);
try
if AResponse <> nil then // Checks if a server response is received
begin
if AResponse.IsSuccess and (AResponse.Features.Count > 0) then // Checks if the query is successful
APushpin.Hint := AResponse.Features.First.Properties.Address.FormattedAddress;
end;
finally
AResponse.Free; // Deletes the query result regardless of the operation's success
end;
end;
#Other Azure Maps Information Providers
- TdxMapControlAzureMapGeocodeProvider
- An Azure Maps Geocode information provider.
- TdxMapControlAzureMapGeolocationProvider
- An Azure Maps Geolocation information provider.
- TdxMapControlAzureMapRouteProvider
- An Azure Maps Route information provider.
#Indirect TdxMapControlAzureMapReverseGeocodeProvider Class References
The following public API members reference the TdxMapControlAzureMapReverseGeocodeProvider
class as a TdxMapControlInformationProvider object:
- TdxMapControlInformationProviders.Add
- Creates an auxiliary map information provider of the required type and adds the provider to the collection.
- TdxMapControlInformationProviders.Items
- Provides indexed access to stored map information provider components.
#Direct TdxMapControlAzureMapReverseGeocodeProvider Class Reference
The TdxMapControlInformationProviderClass references the TdxMapControlAzureMapReverseGeocodeProvider
class.
#Related Compiled Demo
To see Microsoft Azure Map tile and information providers in action, run the Mapping demo in the VCL Demo Center installed with compiled DevExpress demos. When the demo is opened, it downloads tile data and additional information from Azure Map servers to display a map and build routes between specified points.
Tip
Compiled DevExpress demos ship with source code installed in the Public Documents folder (%Public%) for all users (default). You can find all project and source code files for the Map Control demo in the following folder:
%Public%\Documents\DevExpress VCL Demos\Mega