title: Angular 2 urlencoded in http post
body: <p>I try to consume a service via post whit angular2. This my code:</p>
  
  <pre><code> var m_dataRequest = this.buildLoginUserPasswordRequest(password, key);
      let headers = new Headers({
           'Accept': '*/*',
           'Accept-Encoding': 'gzip, deflate, br',
           'Accept-Language': 'es-ES,es;q=0.8,en;q=0.6',
           'Content-Type': 'application/x-www-form-urlencoded',
          });
  
          let options = new RequestOptions({ headers: headers });
          let body = new URLSearchParams();
  
          body.set("message", JSON.stringify(m_dataRequest));
          body.set("webService", "authService");
  
            return this.http
                   .post(this.Url, body.toString(), options)
                   .toPromise()
                   .then(this.extractData)
                   .catch(this.handleError);
  
           private buildLoginUserPasswordRequest(password:string, key:string): any {
  
          var m_dataRequest = {
                      "ser:nativeAppAuth": {
                          "-xmlns:ser": "http://services.mobileappbc.ws.todo1.com/",
                          "password": this.utilService.buidRSAPass(password, t1Assertion),
                          "key": key,
                          "deviceInfo": this.utilService.getDeviceInfo()
                      }
                  };
          return m_dataRequest;
       }
  </code></pre>
  
  <p>The Content-type is application/x-www-form-urlencoded because the backend need the info of this way.
  My problem is the character ":" is not convert to equivalent urlencoded %3A+.
  this cause a problem in my backend service.</p>
  
  <p>any Suggestion for solve this?
  Thanks!</p>