Once you have clientaccesspolicy in place, the code looks like this:You can subscribe to StatusUpdated and\or JobCompleted to see JobInfo. GPString need to include the parameter name "Input" and the value, in this case the string you want to write to file.
var geoprocessorTask = new Geoprocessor("http://gis.mustangeng.com/ArcGIS/rest/services/Geoprocessing/gpServiceTest/GPServer/gpService");
geoprocessorTask.StatusUpdated += (s, e) =>
{
MessageBox.Show(string.Format("StatusUpdated \nID: {0}\nStatus: {1}", e.JobInfo.JobId, e.JobInfo.JobStatus));
};
geoprocessorTask.JobCompleted += (s, e) =>
{
MessageBox.Show(string.Format("JobCompleted \nID: {0}\nStatus: {1}", e.JobInfo.JobId, e.JobInfo.JobStatus));
};
var gpParameters = new List<GPParameter>();
gpParameters.Add(new GPString("Input", "http://mywebsite.com/ArcGIS/rest/services/Geoprocessing/gpServiceTest/GPServer/gpService/submitJob?Input=WOWee"));
geoprocessorTask.SubmitJobAsync(gpParameters);