Stored Procedure view all records based on filters does not accept null value

Question

I have a table that stores records of customers, I would like to filter through these customers but I am having trouble placing a null value into the sproc. The values can be null sometimes and I tested it in sql and it works but It will not accept null value from c# behind. I tried with if statements and the results are the same.

Any help appreciated

you can view the code below

SQL

WHERE ( ProcessStatus.ProcessStatusKey = @ProcessStatusKey OR @ProcessStatusKey IS NULL )
    AND
    ( PriorityLevels.PriorityLevelKey = @PriorityLevelKey OR @PriorityLevelKey IS NULL )
    AND
    ( SystemUsers.SystemUserKey = @SystemUserKey OR @SystemUserKey IS NULL )
    AND
    ( CaseHoganData.LoanAccountNumber = @AccountNumber OR @AccountNumber IS NULL )
    AND
    ( ( LTRIM(RTRIM(( ISNULL(Customers.FirstName, '') + ' ' + ISNULL(Customers.LastName, '') ))) ) LIKE '%'
    + @CustomerName + '%'OR @CustomerName IS NULL )

ASP.NET

    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand("sp_Cases_ViewAll", con))
        {
            //if (prioritylev == "")
            //    cmd.Parameters.AddWithValue("@PriorityLevelKey", DBNull.Value);
            //else


            cmd.Parameters.AddWithValue("@PriorityLevelKey", (string.IsNullOrEmpty(prioritylev) ? (Guid?)null : new Guid(prioritylev)));

            cmd.Parameters.AddWithValue("@ProcessStatusKey", (string.IsNullOrEmpty(processkey) ? (Guid?)null : new Guid(processkey)));
            cmd.Parameters.AddWithValue("@SystemUserKey", (string.IsNullOrEmpty(systemuser) ? (Guid?)null : new Guid(systemuser)));
            cmd.Parameters.AddWithValue("@AccountNumber", accnumber);
            cmd.Parameters.AddWithValue("@CustomerName", cusname);
            using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
            {
                cmd.CommandType = System.Data.CommandType.StoredProcedure;
                DataTable dt = new DataTable();
                sda.Fill(dt);
                grid_Cases.DataSource = dt;
                grid_Cases.DataBind();

            }
        }
    }

EDIT This worked for me

cmd.Parameters.AddWithValue("@PriorityLevelKey", (string.IsNullOrEmpty(prioritylev) ? (object)DBNull.Value : new Guid(prioritylev)));

Answer 1

You were on the right path on your commented code "DBNull.value", here is your changed code:

            using (SqlCommand cmd = new SqlCommand("sp_Cases_ViewAll", con))
            {
                //if (prioritylev == "")
                //    cmd.Parameters.AddWithValue("@PriorityLevelKey", DBNull.Value);
                //else


                if (string.IsNullOrEmpty(prioritylev))
                {
                    cmd.Parameters.AddWithValue("@PriorityLevelKey", DBNull.Value);
                }
                else
                {
                    cmd.Parameters.AddWithValue("@PriorityLevelKey", new Guid(prioritylev));
                }


                if(string.IsNullOrEmpty(processkey))
                {
                    cmd.Parameters.AddWithValue("@ProcessStatusKey", DBNull.Value);
                }
                else
                {
                    cmd.Parameters.AddWithValue("@ProcessStatusKey", new Guid(processkey));
                }


                if (string.IsNullOrEmpty(systemuser))
                {
                    cmd.Parameters.AddWithValue("@SystemUserKey", DBNull.Value);
                }
                else
                {
                    cmd.Parameters.AddWithValue("@SystemUserKey",  new Guid(systemuser));
                }


                cmd.Parameters.AddWithValue("@AccountNumber", accnumber);

                cmd.Parameters.AddWithValue("@CustomerName", cusname);
                using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
                {
                    cmd.CommandType = System.Data.CommandType.StoredProcedure;
                    DataTable dt = new DataTable();
                    sda.Fill(dt);
                    grid_Cases.DataSource = dt;
                    grid_Cases.DataBind();

                }
            }
        }

Answer 2

NULL is represented by the DBNull class:

https://msdn.microsoft.com/en-us/library/system.dbnull(v=vs.110).aspx

Use DBNull.Value when no value is present.