Отправить post запрос на JSON

webBrowser1.Navigate("http://pro.realty.mail.ru/addblock/");
            String postData = "block_uid=&last_version=&created_at=&payer_id=5006502&bargain_type=sale&type_id=9&client_id=5006691&price_origin=1111111111&currency=RUR&unit_type=total&description=http%3A%2F%2Fpro.realty.mail.ru%2Fadd%2FjsonSave%2Fhttp%3A%2F%2Fpro.realty.mail.ru%2Fadd%2FjsonSave%2Fhttp%3A%2F%2Fpro.realty.mail.ru%2Fadd%2FjsonSave%2Fhttp%3A%2F%2Fpro.realty.mail.ru%2Fadd%2FjsonSave%2Fhttp%3A%2F%2Fpro.realty.mail.ru%2Fadd%2FjsonSave%2Fhttp%3A%2F%2Fpro.realty.mail.ru%2Fadd%2FjsonSave%2Fhttp%3A%2F%2Fpro.realty.mail.ru%2Fadd%2FjsonSave%2Fhttp%3A%2F%2Fpro.realty.mail.ru%2Fadd%2FjsonSave%2Fhttp%3A%2F%2Fpro.realty.mail.ru%2Fadd%2FjsonSave%2Fhttp%3A%2F%2Fpro.realty.mail.ru%2Fadd%2FjsonSave%2Fhttp%3A%2F%2Fpro.realty.mail.ru%2Fadd%2FjsonSave%2F%D0%BC&classificators%5Brooms_count%5D%5Bvalue%5D=5&classificators%5Bcommon_area%5D%5Bvalue%5D=66&classificators%5Bkitchen_area%5D%5Bvalue%5D=22&classificators%5Bliving_area%5D%5Bvalue%5D=44&classificators%5Bfloor%5D%5Bvalue%5D=5&classificators%5Bfloors_count%5D%5Bvalue%5D=12&classificators%5Brenovation%5D%5Bvalue_id%5D=0&classificators%5Bflat_type%5D%5Bvalue_id%5D=0&classificators%5Bbathroom_type%5D%5Bvalue_id%5D=0&classificators%5Brooms_area%5D%5Bvalue%5D=&classificators%5Bhouse_type%5D%5Bvalue_id%5D=0&classificators%5Bbuilding_year%5D%5Bvalue%5D=&classificators%5Bname%5D%5Bvalue%5D=&classificators%5Bbuilding_serial%5D%5Bvalue%5D=&classificators%5Bceil_height%5D%5Bvalue%5D=&latitude=53.889947&longitude=27.573334&object_id%5B%5D=1111374&object_id%5B%5D=1111375&geo_relations%5Bsubway%5D%5Bobject_id%5D=0&geo_relations%5Bsubway%5D%5Bvalue%5D=&geo_relations%5Bsubway%5D%5Brelation_type_id%5D=4&raw_address=%D0%B7%D0%B0%D1%81%D0%BB%D0%B0%D0%B2%D1%81%D0%BA%D0%B0%D1%8F+25&company_name=Vlad+Shelepkov&contact_phone-country=1111374&contact_phone=%2B375+(29)+752-86-77&contact_email=crag.hack%40mail.ru&external_url=&is_agreed=1";
            byte[] Bytes = Encoding.UTF8.GetBytes(postData);
            string AdditionalHeaders = "Content-Type: application/x-www-form-urlencoded" + Environment.NewLine;
            webBrowser1.Navigate("http://pro.realty.mail.ru/add/jsonSave/", "", Bytes, AdditionalHeaders);

while (webBrowser1.ReadyState != WebBrowserReadyState.Complete)
            {
                Application.DoEvents();
            }
            timer1.Start();

SendKeys.Send("{ENTER}");
            timer1.Stop();

function GetRequest([string] $url, [System.Net.CookieContainer] $cookieContainer, [string] $postParams, [string] $userAgent)
{
        [system.Net.HttpWebRequest] $request = [system.Net.HttpWebRequest]::Create($url)
        $request.CookieContainer = $cookieContainer
        $request.UserAgent = $userAgent
        
        if (![string]::IsNullOrEmpty($postParams))
        {
            $request.Method = "POST"
            $request.ContentType = "application/x-www-form-urlencoded"
            $request.ContentLength = $postParams.Length
            [System.IO.TextWriter] $requestWriter = New-Object System.IO.StreamWriter($request.GetrequestStream())
            $requestWriter.Write($postParams)
            $requestWriter.Close()
            $requestWriter.Dispose();
        }
        
        return [system.Net.HttpWebRequest] $request
}
 
function GetContentFromUrl([System.String] $url, [System.Net.CookieContainer] $cookieContainer, [System.String] $postParams, [string] $userAgent)
{
        try
        {
            $request = GetRequest $url $cookieContainer $postParams $userAgent
            $Response = $request.GetResponse()
 
            [System.IO.TextReader] $contentStream = New-Object System.IO.StreamReader($Response.GetResponseStream())
            $content = [System.Web.HttpUtility]::HtmlDecode($contentStream.ReadToEnd())
            $contentStream.Close()
            $Response.Close()
 
            if($Response.StatusCode -ne 200)
            {
                throw 'non-200 status code'
            }
        
            if ($content.Contains('Забыли пароль?'))
            {
                throw 'Неверные логин-пароль'
            }
            
            return $content
        }
        catch [System.Net.WebException]
        {
            try
            {
                #       Write-Host $Error[0] -foregroundcolor "magenta"
                $exception = $_.Exception 
                $status = GetStatusDescription( $exception.Status)
                
                $Error = GetExceptionDetails( $exception)
                $errorInfo = GetErrorInfo($exception)
                $errorDescription = GetErrorDescription($exception)
                
                $responseText = GetFailedResponseText -exception ($exception)
                
                if($exception.Response -ne $null)
                {
                    $exception.Response.Close()
                }
            
                SetResult -result $false -info $errorInfo -properties (GetAdditionalProperties -pingUrl $url -responseUri $exception.Response.ResponseUri -httpResponseStatusCode ($exception.Response.StatusCode) -errorCode ($ErrorCode.WebError) -errorDescription $errorDescription -responseText ($responseText))            
                Exit
            }
            catch [System.Exception]
            {
                [System.String] $resultText = "При получении ответа произошла ошибка :{0} {1} {2} " -f ($status, $exception, $exception.GetType())
                SetResult -result $false -info $errorInfo -properties (GetAdditionalProperties -pingUrl $url -resultCount 0 -errorDescription $errorDescription -httpResponseStatusCode 0) 
                Exit
            }
        }     
}