"Procedure or function 'AddProject' expects parameter '@email', which was not supplied." except I did supply it?

Question

First, I want to apologize because my question involves c#, but I can't figure out whether the source of the error is from the c# side or from the SQL Server side.

I have the following stored procedure:

CREATE PROCEDURE [dbo].[AddProject]
	@email varchar(320),
	@project varbinary(max),
	@ProjectName varchar(32)
AS
BEGIN
	SET NOCOUNT ON;
	INSERT INTO Projects (Project, CreationDate, ProjectName) VALUES (@project,  GETDATE(), @ProjectName);
	DECLARE @ID INT = SCOPE_IDENTITY();
    INSERT INTO ProjectsUsers VALUES (@email, @ID);
	SELECT @ID;
END

I am trying to call the stored procedure using the function:

public static int InsertNewProjectIntoDB(string Email, string ProjectName, EmployeeTree employeeTree)
        {
            const string SQL_SP = "dbo.AddProject";
            using (var conn = new SqlConnection(ConnectionString))
            using (var command = new SqlCommand(SQL_SP, conn)
            {
                CommandType = CommandType.StoredProcedure
            })
            {
                command.Parameters.AddWithValue("@email", Email);
                command.Parameters.AddWithValue("@project", ObjectToByteArray(employeeTree));
                command.Parameters.AddWithValue("@ProjectName", ProjectNameq);
                conn.Open();
                return (int)(command.ExecuteScalar());
            }
        }

When I do it, I get the error: "Procedure or function 'AddProject' expects parameter '@email', which was not supplied."

But as you can see from the code, I did supply the "email" parameter, yet I got the error.

What am I doing wrong? 

Answer 1

Does it work in these experiments:

   …AddWithValue("@email", "[e-mail]")

or

   …AddWithValue("@email", ((object)Email) ?? DBNull.Value)   ?

Answer 2

The code you posted looks ok, although I suggest you avoid AddWithValue.

The error indicates the EMail string value is a .NET null value. If your intent is to insert a NULL value for email, use DBNull.Value instead.

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Dan Guzman, Data Platform MVP, http://www.dbdelta.com