在我的数据库中，我具有NextStatDistanceTime值作为浮点数。执行“ float time = reader.GetFloat(0);”行时，出现错误

系统无效的强制转换异常

如何在此代码中从sql命令获取浮点值？

这是我的代码：

using (SqlConnection conn = new SqlConnection(@"<myconnectionstring>"))
{
    float totaltime = 0;
    for (int i = startStationIndex; i < endStationIndex; i++)
    {
        SqlCommand command = new SqlCommand("SELECT NextStatDistanceTime FROM [MetroDatabase].[dbo].[MetroStation] WHERE StationIndex = " + i + "", conn);
        try
        {
            conn.Open();
            command.ExecuteNonQuery();
            using (SqlDataReader reader = command.ExecuteReader())
            {
                while (reader.Read())
                {
                    float time = reader.GetFloat(0);
                    totaltime = totaltime + time;
                    conn.Close();
                }
            }                        
        }
        catch (Exception ex)
        {
            result = ex.Message;
            Console.WriteLine(ex.Message);
        }
    }

}