System.InvalidOperationException: There is an error in XML document (0, 0). ---> System.Xml.XmlException: Root element is missing.

Question

System.InvalidOperationException: There is an error in XML document (0, 0). ---> System.Xml.XmlException: Root element is missing.

Julio Bello 221

Hi, Everybody!...

I am trying to parse the following XML string...

<PostShipmentResponse>
	<Account>L303061</Account>
	<ParcelhubShipmentId>2815849350974933</ParcelhubShipmentId>
	<Reference1>ordernumber1</Reference1>
	<Reference2>label reference</Reference2>
	<SpecialInstructions>leave in shed</SpecialInstructions>
	<ContentsDescription>overview of what's being sent</ContentsDescription>
	<Blobs />
	<ModifiedTime>2023-09-27T18:20:59.9200581+01:00</ModifiedTime>
	<CurrencyCode>GBP</CurrencyCode>
	<Deleted>false</Deleted>
	<HasBeenManifested>false</HasBeenManifested>
	<Department>L3030611</Department>
	<Attributes />
	<Returnable>false</Returnable>
</PostShipmentResponse>

I applied the following XML attributes...

    public partial class PostShipmentResponse
    {
        //[XmlElement(ElementName = "Shipment")]
        //public Shipment Shipment { get; set; }

        [XmlElement(ElementName = "Account")]
        public string Account { get; set; }

        //[XmlElement(ElementName = "ServiceInfo")]
        //public ServiceInfo ServiceInfo { get; set; }

        [XmlElement(ElementName = "ParcelhubShipmentId")]
        public string ParcelhubShipmentId { get; set; }

        //[XmlElement(ElementName = "ShippingInfo")]
        //public ShippingInfo ShippingInfo { get; set; }

        //[XmlElement(ElementName = "CollectionDetails")]
        //public CollectionDetails CollectionDetails { get; set; }

        //[XmlElement(ElementName = "CollectionAddress")]
        //public CollectionAddress CollectionAddress { get; set; }

        //[XmlElement(ElementName = "DeliveryAddress")]
        //public DeliveryAddress DeliveryAddress { get; set; }

        //[XmlElement(ElementName = "DeliverToStoreOrLockerID")]
        //public string DeliverToStoreOrLockerID { get; set; }

        [XmlElement(ElementName = "Reference1")]
        public string Reference1 { get; set; }

        [XmlElement(ElementName = "Reference2")]
        public string Reference2 { get; set; }

        [XmlElement(ElementName = "SpecialInstructions")]
        public string SpecialInstructions { get; set; }

        [XmlElement(ElementName = "ContentsDescription")]
        public string ContentsDescription { get; set; }

        //[XmlElement(ElementName = "Packages")]
        //public Packages Packages { get; set; }

        //[XmlElement(ElementName = "Enhancements")]
        //public Enhancements Enhancements { get; set; }

        [XmlElement(ElementName = "Blobs")]
        public string Blobs { get; set; }

        [XmlElement(ElementName = "ModifiedTime")]
        public string ModifiedTime { get; set; }

        [XmlElement(ElementName = "CurrencyCode")]
        public string CurrencyCode { get; set; }

        //[XmlElement(ElementName = "CustomsDeclarationInfo")]
        //public CustomsDeclarationInfo CustomsDeclarationInfo { get; set; }

        [XmlElement(ElementName = "Deleted")]
        public string Deleted { get; set; }

        [XmlElement(ElementName = "HasBeenManifested")]
        public string HasBeenManifested { get; set; }

        //[XmlElement(ElementName = "ShipmentTags")]
        //public ShipmentTags ShipmentTags { get; set; }

        //[XmlElement(ElementName = "Stream")]
        //public string Stream { get; set; }

        [XmlElement(ElementName = "Department")]
        public string Department { get; set; }

        [XmlElement(ElementName = "Attributes")]
        public string Attributes { get; set; }

        [XmlElement(ElementName = "Returnable")]
        public string Returnable { get; set; }

        //[XmlElement(ElementName = "NominatedDeliveryDate")]
        //public NominatedDeliveryDate NominatedDeliveryDate { get; set; }

        //[XmlElement(ElementName = "ProductTypeCode")]
        //public string ProductTypeCode { get; set; }

        //[XmlAttribute(AttributeName = "xsd")]
        //public string Xsd { get; set; }

        //[XmlAttribute(AttributeName = "xsi")]
        //public string Xsi { get; set; }

        //[XmlAttribute(AttributeName = "xmlns")]
        //public string Xmlns { get; set; }

        //[XmlText]
        //public string Text { get; set; }
    }

I'm executing the following code...

        private TResponse XmlStringToObject<TResponse>(string xmlString)
        {
            using (var memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(xmlString)))
            {
                XmlSerializer xmlSerializer;

                xmlSerializer = new XmlSerializer(typeof(TResponse));

                return (TResponse)xmlSerializer.Deserialize(memoryStream);
            }
        }

I'm getting the followig error...

System.InvalidOperationException: There is an error in XML document (0, 0). ---> System.Xml.XmlException: Root element is missing.

What am I going wrong?

Accepted answer

1 additional answer

Your answer

Answer 1

Viorel 122.5K

It seems that you must execute memoryStream.Position = 0 between attempts.

Julio Bello 221

Hi, @Viorel

Your comment was precisely the correct answer. My code now looks like this...

    private TResponse XmlStringToObject<TResponse, TError>(string xmlString, ref TError error) where TResponse : class
    {
        using (var memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(xmlString)))
        {
            XmlSerializer xmlSerializer;

            //Check for Error Response first
            try
            {
                xmlSerializer = new XmlSerializer(typeof(TError));
                error = (TError)xmlSerializer.Deserialize(memoryStream);

                if (error != null)
                    return null;
            }
            catch (InvalidOperationException)
            {
                // Apparently, it is not an Error Response
                memoryStream.Position = 0;
            }

            // No Error Response
            xmlSerializer = new XmlSerializer(typeof(TResponse));

            return (TResponse)xmlSerializer.Deserialize(memoryStream);
        }
    }

Answer 2

Hi @Julio Bello,

I tested the code you provided and there is no problem. You didn't provide a method to read the xml, maybe that's a problem.

You can add the following content to your XML and see if an error is reported.

<?xml version="1.0" encoding="utf-8"?>
<rootElement>
...
</rootElement>

Or try using my test method, here is the complete test code:

public class Program
{
    public static void Main(string[] args)
    {
        Serializer ser = new Serializer();
        string path = string.Empty;
        string xmlInputData = string.Empty;
        xmlInputData = File.ReadAllText(@"C:\Users\Administrator\Desktop\test.xml");
        var customer = ser.XmlStringToObject<PostShipmentResponse>(xmlInputData);
        Console.WriteLine(customer);

    }
    public class Serializer
    {
        public TResponse XmlStringToObject<TResponse>(string xmlString)
        {
            using (var memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(xmlString)))
            {
                XmlSerializer xmlSerializer;

                xmlSerializer = new XmlSerializer(typeof(TResponse));

                return (TResponse)xmlSerializer.Deserialize(memoryStream);
            }
        }
    }


    public partial class PostShipmentResponse
    {
        //[XmlElement(ElementName = "Shipment")]
        //public Shipment Shipment { get; set; }

        [XmlElement(ElementName = "Account")]
        public string Account { get; set; }

        //[XmlElement(ElementName = "ServiceInfo")]
        //public ServiceInfo ServiceInfo { get; set; }

        [XmlElement(ElementName = "ParcelhubShipmentId")]
        public string ParcelhubShipmentId { get; set; }

        //[XmlElement(ElementName = "ShippingInfo")]
        //public ShippingInfo ShippingInfo { get; set; }

        //[XmlElement(ElementName = "CollectionDetails")]
        //public CollectionDetails CollectionDetails { get; set; }

        //[XmlElement(ElementName = "CollectionAddress")]
        //public CollectionAddress CollectionAddress { get; set; }

        //[XmlElement(ElementName = "DeliveryAddress")]
        //public DeliveryAddress DeliveryAddress { get; set; }

        //[XmlElement(ElementName = "DeliverToStoreOrLockerID")]
        //public string DeliverToStoreOrLockerID { get; set; }

        [XmlElement(ElementName = "Reference1")]
        public string Reference1 { get; set; }

        [XmlElement(ElementName = "Reference2")]
        public string Reference2 { get; set; }

        [XmlElement(ElementName = "SpecialInstructions")]
        public string SpecialInstructions { get; set; }

        [XmlElement(ElementName = "ContentsDescription")]
        public string ContentsDescription { get; set; }

        //[XmlElement(ElementName = "Packages")]
        //public Packages Packages { get; set; }

        //[XmlElement(ElementName = "Enhancements")]
        //public Enhancements Enhancements { get; set; }

        [XmlElement(ElementName = "Blobs")]
        public string Blobs { get; set; }

        [XmlElement(ElementName = "ModifiedTime")]
        public string ModifiedTime { get; set; }

        [XmlElement(ElementName = "CurrencyCode")]
        public string CurrencyCode { get; set; }

        //[XmlElement(ElementName = "CustomsDeclarationInfo")]
        //public CustomsDeclarationInfo CustomsDeclarationInfo { get; set; }

        [XmlElement(ElementName = "Deleted")]
        public string Deleted { get; set; }

        [XmlElement(ElementName = "HasBeenManifested")]
        public string HasBeenManifested { get; set; }

        //[XmlElement(ElementName = "ShipmentTags")]
        //public ShipmentTags ShipmentTags { get; set; }

        //[XmlElement(ElementName = "Stream")]
        //public string Stream { get; set; }

        [XmlElement(ElementName = "Department")]
        public string Department { get; set; }

        [XmlElement(ElementName = "Attributes")]
        public string Attributes { get; set; }

        [XmlElement(ElementName = "Returnable")]
        public string Returnable { get; set; }

        //[XmlElement(ElementName = "NominatedDeliveryDate")]
        //public NominatedDeliveryDate NominatedDeliveryDate { get; set; }

        //[XmlElement(ElementName = "ProductTypeCode")]
        //public string ProductTypeCode { get; set; }

        //[XmlAttribute(AttributeName = "xsd")]
        //public string Xsd { get; set; }

        //[XmlAttribute(AttributeName = "xsi")]
        //public string Xsi { get; set; }

        //[XmlAttribute(AttributeName = "xmlns")]
        //public string Xmlns { get; set; }

        //[XmlText]
        //public string Text { get; set; }
    }
}

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Best regards,
Lan Huang

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Julio Bello 221 Reputation points

2023-09-28T07:24:27.92+00:00

Thank-you for trying to help me with my issue.

Perhaps the reason why my error was not reproducible is because I "simplified" the method I executed to "abbreviate" the problem statement.

What I am REALLY trying to do is to parse either one of TWO possible XML strings. One is a PostShipmentResponse (which was already defined). The other is an Error response (See below).

[XmlRoot(ElementName = "Error"] public partial class Error { [XmlElement(ElementName = "Message")] public string Message { get; set; } }

My approach was to first check for a possible Error response. If not, then assume a PostShipmentResponse (See below).

private TResponse XmlStringToObject<TResponse, TError>(string xmlString, ref TError error) where TResponse : class { using (var memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(xmlString))) { XmlSerializer xmlSerializer; //Check for Error Response first try { xmlSerializer = new XmlSerializer(typeof(TError)); error = (TError)xmlSerializer.Deserialize(memoryStream); if (error != null) return null; } catch (InvalidOperationException) { // Apparently, it is not an Error Response } // No Error Response xmlSerializer = new XmlSerializer(typeof(TResponse)); return (TResponse)xmlSerializer.Deserialize(memoryStream); } }

When you confirmed that NOTHING was wrong with the original method, I then commented out the "Error response" block of code and voilà ... It worked!

Apparently, when the attempting to parse an Error response fails (in the event of a PostShipmentResponse), the second attempt also fails. Is there a way to "clear" all exceptions before attempting to parse a PostShipmentResponse?
Lan Huang-MSFT 30,186 Reputation points Microsoft External Staff

2023-09-28T09:52:45.9433333+00:00

Hi @Julio Bello,

From my understanding, you have two responses, one is PostShipmentResponse and other is Error response.

You want to deserialize both responses. When deserialization fails, an InvalidOperationException is thrown. I don't quite understand your comment:(// Apparently, it is not an Error Response).

You can refer to the code below (untested) and modify your own code.

private (TResponse, TError) XmlStringToObject<TResponse, TError>(string xmlString, ref string error) where TResponse : class { (TResponse,TError ) result = (default,default) ; try { XmlSerializer xmlSerializer; if (error == null) { var memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(xmlString)); xmlSerializer = new XmlSerializer(typeof(TResponse)); result.Item1 = (TResponse)xmlSerializer.Deserialize(memoryStream); } else { var memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(error)); xmlSerializer = new XmlSerializer(typeof(TError)); result.Item2 = (TError)xmlSerializer.Deserialize(memoryStream); } } catch (InvalidOperationException e) { Console.WriteLine(e.InnerException); } return (result.Item1,result.Item2); }
Julio Bello 221 Reputation points

2023-09-28T14:28:56.64+00:00

Hi, @Lan Huang-MSFT

I wish to thank-you again for your efforts... When you confirmed that NOTHING was wrong with the original method, that made me ask: Is there a way to "clear" all exceptions before attempting to parse a PostShipmentResponse?

Viorel's response was precisely what I was missing in my code.

Truly grateful

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System.InvalidOperationException: There is an error in XML document (0, 0). ---> System.Xml.XmlException: Root element is missing.

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