SQL 错误:过程或函数“创建用户帐户”需要参数“@FirstName”，但未提供

我已经调试了代码，从我所看到的情况来看，我确实添加了带有值的参数，但是任何人都可以帮助解决这个问题吗？我不认为我能看到任何问题，但我的另一双眼睛可能会有所帮助。

方法

    public bool CreateUserAccount(string firstName, string lastName, string aboutUser, string email, string password, 
        string addressLine1, string addressLine2, string city, string postcode, string contactNumber)
    {
        bool registered = false;
        try
        {
            connection = OpenSqlConnection();
            command = new SqlCommand(CREATE_USER_ACCOUNT, connection);
            command.Parameters.AddWithValue(FIRST_NAME, firstName);
            command.Parameters.AddWithValue(LAST_NAME, lastName);
            command.Parameters.AddWithValue(ABOUT_USER, aboutUser);
            command.Parameters.AddWithValue(USER_EMAIL, email);
            command.Parameters.AddWithValue(USER_PASSWORD, password);
            command.Parameters.AddWithValue(ADDRESS_LINE_1, addressLine1);
            command.Parameters.AddWithValue(ADDRESS_LINE_2, addressLine2);
            command.Parameters.AddWithValue(CITY, city);
            command.Parameters.AddWithValue(POSTCODE, postcode);
            command.Parameters.AddWithValue(CONTACT_NUMBER, contactNumber);
            registered = Convert.ToBoolean(command.ExecuteNonQuery());
        }
        catch (Exception ex)
        {
            throw ex;
        }
        return registered;
    }

.SQL

ALTER PROC CreateUserAccount
(
@FirstName VARCHAR(50),
@LastName VARCHAR(50),
@AboutUser VARCHAR(3000),
@UserEmail VARCHAR(200),
@UserPassword VARCHAR(50),
@AddressLine1 VARCHAR(50),
@AddressLine2 VARCHAR(50),
@City VARCHAR(50),
@Postcode VARCHAR(50),
@ContactNumber VARCHAR(50)
)
AS BEGIN
DECLARE @Registered INT
IF(NOT EXISTS(SELECT * FROM [User] WHERE usr_Email = @UserEmail))
BEGIN
    INSERT INTO [User]
    VALUES
        (
            NEWID(),
            @FirstName,
            @LastName,
            @AboutUser,
            @UserEmail,
            @UserPassword,
            @AddressLine1,
            @AddressLine2,
            @City,
            @Postcode,
            @ContactNumber
        )
    SET @Registered = 1
    PRINT 'Implemented' -- for testing purposes
END
ELSE
BEGIN
    SET @Registered = 0
    PRINT 'Not implemented' -- for testing purposes
END
RETURN @Registered
END

public bool CreateUserAccount(string firstName, string lastName, string aboutUser, string email, string password, 
    string addressLine1, string addressLine2, string city, string postcode, string contactNumber)
{
    bool registered = false;
    try
    {
        connection = OpenSqlConnection();
        command = new SqlCommand(CREATE_USER_ACCOUNT, connection);
        command.CommandType = CommandType.StoredProcedure;
        command.Parameters.AddWithValue(FIRST_NAME, firstName);
        command.Parameters.AddWithValue(LAST_NAME, lastName);
        command.Parameters.AddWithValue(ABOUT_USER, aboutUser);
        command.Parameters.AddWithValue(USER_EMAIL, email);
        command.Parameters.AddWithValue(USER_PASSWORD, password);
        command.Parameters.AddWithValue(ADDRESS_LINE_1, addressLine1);
        command.Parameters.AddWithValue(ADDRESS_LINE_2, addressLine2);
        command.Parameters.AddWithValue(CITY, city);
        command.Parameters.AddWithValue(POSTCODE, postcode);
        command.Parameters.AddWithValue(CONTACT_NUMBER, contactNumber);
        registered = Convert.ToBoolean(command.ExecuteNonQuery());
    }
    catch (Exception ex)
    {
        throw ex;
    }
    return registered;
}