Procedure or Function 'ValidateUserLogin' expects parameter '@UserName', which was not supplied

Question

I have this stored procedure for validating login

ALTER PROCEDURE ValidateUserLogin
(
@UserName varchar (50),
@Password varchar (50)
)
AS
BEGIN
if EXISTS(SELECT * FROM AdminLogin WHERE UserName=@UserName AND Password=@Password)
select 0/*returns 0 on success*/
ELSE
select 1/*non zero otherwise*/

END

and i am calling it using the code below but i get the following exception "Procedure or Function 'ValidateUserLogin' expects parameter '@UserName', which was not supplied."

   bool boolReturnValue = true;

    SqlCommand command = new SqlCommand();
    command.Connection = sqlConnection;
    command.CommandType = CommandType.StoredProcedure;
    command.CommandText = "ValidateUserLogin";
    command.Parameters.Add(@username,SqlDbType.VarChar,50).Value=username;
    command.Parameters.Add(@password, SqlDbType.VarChar,50).Value=password;
    sqlConnection.Open();
    try
    {
    command.ExecuteScalar();
       boolReturnValue=Convert.ToBoolean( command.ExecuteScalar());
    }
    catch (Exception ex)
    {
        Response.Write(ex.Message);
    }

and when i try to set default value for the username and password as null i get the exception @admin is not a parameter for procedure ValidateUserLogin //admin is the value provided for username

Answer 1

Change the following two lines:

command.Parameters.Add(@username,SqlDbType.VarChar,50).Value=username;
command.Parameters.Add(@password, SqlDbType.VarChar,50).Value=password;

with:

command.Parameters.Add("@Username",SqlDbType.VarChar,50).Value=username;
command.Parameters.Add("@Password", SqlDbType.VarChar,50).Value=password;

Answer 2

You need to put your parameter name in quotes for the Add method. In other words, "@username" with the quotes.