How can I access the web service through my application

This article describes how to call the web services from your application. The MSSoap client ole object will allow the application to make remote procedure calls to the web server over the internet. So we need to create a ole object i.e the "MSSoap.Soapclient" in our application. For this, Microsoft Soap ToolKit must be installed in the machine where the application is running.

For this example will be using the "CurrencyExchangeService" webservice which is provided by "www.xmethods.net". This web service gives the currency value of the Country2 with respect to Country1.

function getrate( Country1, Country2 : String ) : Double;
var SoapClient: OleVariant;
    vRate : String;
    vURL : String;
begin
    vURL := 'http://www.xmethods.net/sd/CurrencyExchangeService.wsdl';
    vRate := 0;
    Try
      SoapClient := CreateOleObject('MSSOAP.SoapClient');
    except
    end;
    try
      SoapClient.mssoapinit( vURL );
      //GetRate is the function in the Web service
      vRate := SoapClient.GetRate( Country1, Country2 );
    except
    end;
    try
      FreeAndNil( SoapClient );
    except
    end;  
    Result := StrToFloat( vRate );
end;