转换函数

public static DateTime ToStartDateTime(string startDate)
    {
        try
        {
            return Convert.ToDateTime(startDate);
        }
        catch 
        {
            return DateTime.MinValue;
        }
    }

    public static DateTime ToEndDateTime(string endDate)
    {
        try
        {
            return Convert.ToDateTime(endDate);
        }
        catch
        {
            return DateTime.MaxValue;
        }
    }

    public static DateTime ToSqlServerStartDateTime(string endDate)
    {
        try
        {
            return Convert.ToDateTime(endDate);
        }
        catch
        {
            return new DateTime(1753, 1, 1);
        }
    }

    public static DateTime ToSqlServerEndDateTime(string endDate)
    {
        try
        {
            return Convert.ToDateTime(endDate);
        }
        catch
        {
            return new DateTime(9999, 12, 31);
        }
    }