CODEWITHSUNDEEP
c#.netxmldeserialization
techresearch
techresearch

Reputation: 169

XML Deserialization handle empty tags with Default values

I want to handle the datetime during deserialize. If xml has no node or empty value then I need to set the value to default value of datetime min value or max value based on i have set. So problem here is if xml has startdate with empty value like <startdate></startdate> then i get null instead of DateTime.MinValue. Similarly i may have some other node such as enddate which requires DateTime.MaxValue as default value. If i don't pass the tag startdate then I am getting Minvalue which is expected. So how I can handle for empty tags. I need to get Date Minvalue in case of empty tag as well.

public static void Main()
{
    Program t = new Program();
        
        t.DeserializeObject("<OrderedItem><startdate>20210125</startdate><enddate>20210324</enddate></OrderedItem>");
        t.DeserializeObject("<OrderedItem></OrderedItem>");
        t.DeserializeObject("<OrderedItem><startdate></startdate><enddate></enddate></OrderedItem>"); //In this case i am getting issue, Output will not have default Min and Max Values
}

  private void DeserializeObject(string testData)
    {
        // Create an instance of the XmlSerializer.
        XmlSerializer serializer =
        new XmlSerializer(typeof(OrderedItem));

        // Declare an object variable of the type to be deserialized.
        OrderedItem i;
        using (TextReader reader = new StringReader(testData))
        {
            i = (OrderedItem)serializer.Deserialize(reader);
        }
    Console.Write("Start date is "+i.Startdate.Date+"\n");
    Console.Write("End date is "+i.Enddate.Date+"\n\n");
    
    }

public class OrderedItem
{
    
    [XmlElement(ElementName = "startdate")]
    [DefaultValue(typeof(DateTime), "0001-01-01T00:00:00")]
 public CustomDateTime Startdate { 
        get; 
        set;
    } = new CustomDateTime { Date = DateTime.MinValue };

 [XmlElement(ElementName = "enddate")]
    [DefaultValue(typeof(DateTime), "9999-12-31T00:00:00")]
 public CustomDateTime Enddate { 
        get; 
        set;
    } = new CustomDateTime { Date = DateTime.MaxValue };
}

And in my CustomDateTime I am using IXmlSerializable and below is portion of code

public class CustomDateTime : IXmlSerializable, IComparable, IComparable<DateTime>
{
    static string[] formats = new string[] { "yyyyMMdd", "yyyy-MM-dd" };
    [XmlIgnore]
    public DateTime? Date
    {
        get;
        set;
    }
   // here i have CompareTo and other methods which implements interface
public void ReadXml(XmlReader reader)
    {
        string input = reader.ReadString();

        DateTime inputDate;
        if (DateTime.TryParseExact(input, formats, CultureInfo.InvariantCulture, DateTimeStyles.None, out inputDate))
        {
            Date = inputDate;
        }
        else
        {
            Date = null;
        }
        reader.ReadEndElement();
    }

    public void WriteXml(XmlWriter writer)
    {
        if (Date != null)
        {
            writer.WriteString(Date.Value.ToString("yyyyMMdd"));
        }
    }
}

Actual Output

Start date is 1/25/2021 12:00:00 AM End date is 3/24/2021 12:00:00 AM

Start date is 1/1/0001 12:00:00 AM End date is 12/31/9999 11:59:59 PM

Start date is End date is

Expected Output

Start date is 1/25/2021 12:00:00 AM End date is 3/24/2021 12:00:00 AM

Start date is 1/1/0001 12:00:00 AM End date is 12/31/9999 11:59:59 PM

Start date is 1/1/0001 12:00:00 AM End date is 12/31/9999 11:59:59 PM

Fiddle:https://dotnetfiddle.net/qv7sjP

I thought I can add defaultvalue attribute like [DefaultValue(typeof(DateTime), "0001-01-01T00:00:00")] or [DefaultValue(typeof(DateTime), "9999-12-31T00:00:00")] as required to property Startdate and Enddate and read this in ReadXml method and then set Date property in ReadXml method when tag not present(else block). I am not sure how i can read this and handle it. Also i am not sure is this appropriate solution

Upvotes: 0

Views: 733

Answers (1)

jdweng
jdweng

Reputation: 34421

Try following :

    public class OrderedItem
    {
        private DateTime _Startdate = new DateTime();
        [XmlElement(ElementName = "startdate")]
        public DateTime Startdate { 
            get{ return _Startdate;} 
            set{ _Startdate = value;}
        }

        private DateTime _Enddate = new DateTime();
        [XmlElement(ElementName = "enddate")]
        public DateTime Enddate
        {
            get { return _Enddate; }
            set { _Enddate = value; }
        }
    }

Upvotes: 1

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