When I retrieve data from SQL server the length of string is 200 and the real length much less than 200

private void GetSubjectDetails(int id)
        {
            var conn = new SqlConnection(Connectionstring);
            conn.Open();

            var command = new SqlCommand("SELECT [sub_id],[sub_name],[lev_id],[hours],[status] FROM [DB_SchoolManager].[dbo].[tbl_subjects] where [sub_id]=@sub_id", conn);
            command.Parameters.AddWithValue("@sub_id", id);

            using (SqlDataReader reader = command.ExecuteReader())
            {
                if (reader.Read())
                {
                    TxtSubject.Text = reader["sub_name"].ToString();
                    TxtHours.Text = reader["hours"].ToString();
                    CbLevels.SelectedValue = int.Parse(reader["lev_id"].ToString());
                    if (reader["status"].ToString()=="Blocked")
                    {
                        CbStatus.SelectedIndex = 1;
                    }
                    else
                    {
                        MessageBox.Show(reader["status"].ToString().Length.ToString());
                        CbStatus.SelectedIndex = 0;
                    }
                    
                }
            }
            conn.Close();
        }

CREATE TABLE [dbo].[tbl_subjects](
	[sub_id] [int] IDENTITY(1,1) NOT NULL,
	[sub_name] [nchar](200) NOT NULL,
	[lev_id] [nchar](200) NOT NULL,
	[hours] [nchar](200) NOT NULL,
	[status] [nchar](200) NOT NULL,
 CONSTRAINT [PK_tbl_subjects] PRIMARY KEY CLUSTERED 
(
	[sub_id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 90) ON [PRIMARY]
) ON [PRIMARY]
GO

[nchar](200)