Unable to set Reporting Services Parameters - web-services

Question

I'm generating a reporting services report from an ASP.NET (MVC) based application but am having problems setting the parameters for the report.
I believe the issue has only occurred since we upgraded SQL Server from 2005 to 2008 R2 (and Reporting Services along with it).
The original error encountered was from calling rsExec.Render:
Procedure or function 'pCommunication_ReturnRegistrationLetterDetails'
expects parameter '#guid', which was not supplied.
Debugging the code I noticed that rsExec.SetExecutionParameters is returning the following response:
Cannot call 'NameOfApp.SQLRSExec.ReportExecutionService.SetExecutionParameters(NameOfApp.SQLRSExec.ParameterValue[],
string)' because it is a web method.
Here is the function in it's entirety:
public static bool ProduceReportToFile(string reportname, string filename, string[,] reportparams,
string fileformat)
{
bool successful = false;
SQLRS.ReportingService2005 rs = new SQLRS.ReportingService2005();
SQLRSExec.ReportExecutionService rsExec = new NameOfApp.SQLRSExec.ReportExecutionService();
rs.Credentials = System.Net.CredentialCache.DefaultCredentials;
rsExec.Credentials = System.Net.CredentialCache.DefaultCredentials;
// Prepare Render arguments
string historyID = null;
string deviceInfo = null;
// Prepare format - available options are "PDF","Word","CSV","TIFF","XML","EXCEL"
string format = fileformat;
Byte[] results;
string encoding = String.Empty;
string mimeType = String.Empty;
string extension = String.Empty;
SQLRSExec.Warning[] warnings = null;
string[] streamIDs = null;
// Define variables needed for GetParameters() method
// Get the report name
string _reportName = reportname;
string _historyID = null;
bool _forRendering = false;
SQLRS.ParameterValue[] _values = null;
SQLRS.DataSourceCredentials[] _credentials = null;
SQLRS.ReportParameter[] _parameters = null;
// Get if any parameters needed.
_parameters = rs.GetReportParameters(_reportName, _historyID,
_forRendering, _values, _credentials);
// Load the selected report.
SQLRSExec.ExecutionInfo ei =
rsExec.LoadReport(_reportName, historyID);
// Prepare report parameter.
// Set the parameters for the report needed.
SQLRSExec.ParameterValue[] parameters =
new SQLRSExec.ParameterValue[1];
// Place to include the parameter.
if (_parameters.Length > 0)
{
for (int i = 0; i < _parameters.Length; i++)
{
parameters[i] = new SQLRSExec.ParameterValue();
parameters[i].Label = reportparams[i,0];
parameters[i].Name = reportparams[i, 0];
parameters[i].Value = reportparams[i, 1];
}
}
rsExec.SetExecutionParameters(parameters, "en-us");
results = rsExec.Render(format, deviceInfo,
out extension, out encoding,
out mimeType, out warnings, out streamIDs);
// Create a file stream and write the report to it
using (FileStream stream = System.IO.File.OpenWrite(filename))
{
stream.Write(results, 0, results.Length);
}
successful = true;
return successful;
}
Any ideas why I'm now unable to set parameters? The report generation works without issue if parameters aren't required.

Answer 1

Looks like it may have been an issue with how reporting services passes parameters through to the stored procedure providing the data. A string guid was being passed through to the report and the stored procedure expected a varchar guid. I suspect reporting services may have been noticing the string followed the guid format pattern and so passed it through as a uniqueidentifier to the stored procedure.
I changed the data source for the report from "stored procedure" to "text" and set the SQL as "EXEC pMyStoredOProcName #guid".
Please note the guid being passed in as a string to the stored procedure is probably not best practice... I was simply debugging an issue with another developers code.

Answer 2

Parameter _reportName cannot be null or empty. The [CLASSNAME].[METHODNAME]() reflection API could not create and return the SrsReportNameAttribute object
In this specific case it looks like an earlier full compile did not finish.
If you encounter this problem I would suggest that you first compile the class mentioned in the error message and see if this solves the problem.
go to AOT (get Ctrl+D)
in classes find CLASSNAME
3.compile it (F7)