Getting an error when trying to retrieve data from the datab

Question

Hello,

 

This is the error i get when I try to retrieve data from the database.

 

"The cast to value type 'Single' failed because the materialized value is null. Either the result type's generic parameter or the query must use a nullable type."

 

Here is my code:

public JsonResult AjaxInventory()
{
//Get the id of active election
FormsAuthenticationTicket ticket = FormsAuthentication.Decrypt(Request.Cookies[FormsAuthentication.FormsCookieName].Value);
//0 Username | 1 Fullname | 2 User Id | 3 Login Type | 4 Election Id
string[] UserData = ticket.UserData.Split('|');
// action inside a standard controller
//int filteredResultsCount;
//int totalResultsCount;
//Load information
var result = dbGetItemsList(UserData[4], UserData[2]);
//totalResultsCount = result.Count;
//filteredResultsCount = totalResultsCount;
return Json(new
{
// this is what datatables wants sending back
//draw = 1,
//recordsTotal = totalResultsCount,
//recordsFiltered = filteredResultsCount,
data = result
} //, JsonRequestBehavior.AllowGet
);
}

private List dbGetItemsList(string electionID, string candidateId)
{
//SqlParameter param1 = new SqlParameter("@candidateId", candidateID);
//ElectionID = @electionId and
List lstItems = dbFFS.Database.SqlQuery
("sp_GetContributions @electionId, @candidateId, @officeId, @contributionId,@contributorId, @receiptNoFrom, @receiptNoTo, @amountFrom, @amountTo, @acceptionTimeFrom, @acceptionTimeTo, @contributorTypeAbbr, @relationshipAbbr, @contributionTypeAbbr, @deliveryMethodAbbr",
new SqlParameter("@electionId", electionID),
new SqlParameter("@candidateId", candidateId),
new SqlParameter("@officeId", 7),
new SqlParameter("@contributionId", 1),
new SqlParameter("@contributorId", 26),
new SqlParameter("@receiptNoFrom", DBNull.Value),
new SqlParameter("@receiptNoTo", DBNull.Value),
new SqlParameter("@amountFrom", DBNull.Value),
new SqlParameter("@amountTo", DBNull.Value),
new SqlParameter("@acceptionTimeFrom", DBNull.Value),
new SqlParameter("@acceptionTimeTo", DBNull.Value),
new SqlParameter("@contributorTypeAbbr", DBNull.Value),
new SqlParameter("@relationshipAbbr", DBNull.Value),
new SqlParameter("@contributionTypeAbbr", DBNull.Value),
new SqlParameter("@deliveryMethodAbbr", DBNull.Value)
).ToList();
//Call Stored Procedure
//List lstItems = db.Database.SqlQuery(
// "GetWebInventoryList @electionId, @candidateId",
// new SqlParameter("electionId", electionID),
// new SqlParameter("candidateId", candidateID)
// ).ToList();
return lstItems;
}