Unable to get data from stored procedure

I'm trying to hit the stored procedure from C# code but always get the result == -1. I don't know where I went wrong. I have searched a lot but didn't' find any solution. Please have a look into my code snippet and guide me what I'm doing wrong.

Thanks in advance.

C# code:

using (SqlConnection connection = new SqlConnection(getConnectionString()))
using (SqlCommand command = new SqlCommand())
{
    Int32 rowsAffected;

    command.CommandText = "SP_LOGIN_GETUSERBYNAME";
    command.CommandType = CommandType.StoredProcedure;
    // command.Parameters.Add(new SqlParameter("@Email", userObj.email));
    // command.Parameters.Add("@Email", SqlDbType.VarChar).Value = userObj.email.Trim();
    command.Parameters.AddWithValue("@Email", userObj.email.ToString());
    command.Connection = connection;

    connection.Open();
    rowsAffected = command.ExecuteNonQuery();
    connection.Close();

    return rowsAffected;
}

Connection string:

return "Data Source=MUNEEB-PC;Initial Catalog=HRPayRoll;User ID=sa; Password=sa";

Stored procedure code:

CREATE PROCEDURE SP_LOGIN_GETUSERBYNAME
    @Email varchar(50)
AS
    SELECT *
    FROM [User]
    WHERE Email = @Email
GO