DataTable serialization in SOAP Client

[sudoudaisuke]

I'm converting .net framework winform apps to .net core 3.0. My apps call many SOAP methods. SOAP web service server is implemented by ASP.NET webform based asmx(wdsl). SOAP method returns typed DataTable.

I know that .net core will not support ASP.NET webform. But, if SOAP client (generated by dotnet-svcutil) will not support it, then I cannnot convert client side winform apps to .net core and .NET 5. So please support client side datatable serialization.

#3242 #3378

[StephenBonikowsky]

According to https://referencesource.microsoft.com/#System.Data/System/Data/DataTable.cs,5906

Typed DataTable is not supported in WSDL (SQLBU 444636) That isn't something WCF can do anything about.

If #3378 will solve your problem @sudoudaisuke then that same bug is already tracking that work.

@dasetser Is there anything else you would like to add?

[StephenBonikowsky]

@sudoudaisuke Could you help me understand a few things that are confusing me.

I'm not sure what you mean by a "SOAP method", do you just mean the Server side operation and you are saying that it returns the DataTable type? Any WSDL generated for the Service wouldn't include that type since it isn't supported. So running dotnet-svcutil against that WSDL wouldn't accomplish anything.

If on the other hand you are just getting data from a service operation and on the client side you want to populate a DataTable type with that data you could do it by reading the data in the SOAP message into some other object and then populating a DataTable with it.

[StephenBonikowsky]

No other action we can take on this, please let us know if there is any additional info you can provide or anything else we can help with.

[sudoudaisuke]

Hi @StephenBonikowsky . Thanky for your reply. And sorry for my late reply.

This is my sample Visual Studio solution files, and wsdl, xsd.

TypedDatatTableAsmxSolution.zip

wsdl_and_xsd.zip

If .NET Framework app can generate TypedDataSet from wsdl, but .NET Core app cannot.

I can do like this.

1. Define TypedDataSet in .NET Standard 2.0 lib.
2. Reference the lib, from server (Framework / webservice / asmx) and client (.NET Core).
3. In client, call generated ClientBase<T> method (return XElement not TypedDataTable).
4. In client, create TypedDataTable Instance.
5. In client, call DataTable.ReadeXml method.

var client = new ServiceReference1.WebService1SoapClient(ServiceReference1.WebService1SoapClient.EndpointConfiguration.WebService1Soap);
var data = await client.GetSampleDataTableAsync();

var table = new TypedDataTableDefinition.TypedSampleDataSet.SampleDataTableDataTable();

using (var stream = new MemoryStream()) {
    data.Any1.Save(stream);
    stream.Seek(0, SeekOrigin.Begin);
    table.ReadXml(stream);
}

But, I have many TypedDataSets and many asmx mehods. .NET Core takes time and effort. .NET Framework is better for me. I want that .NET Core can generate TypedDataSet from wsdl and xsd too.

[StephenBonikowsky]

@sudoudaisuke Thanks for the additional info, we'll take a look at this.

[StephenBonikowsky]

@imcarolwang In the additional info provided by @sudoudaisuke he says...

If .NET Framework app can generate TypedDataSet from wsdl, but .NET Core app cannot.

Could you verify using the project and info provided that this works on full framework and fails on .NET Core?

[imcarolwang]

I've confirmed the behavior reported in issue that when generating wcf proxy code, a DataSet/DataTable type could be deserialized as its original type in .NETFramework wcf client app using svcutil.exe, but would be deserialized to other alternatives like System.Xml.Linq.XElement[] in .NETCore with dotnet-svcutil.exe.

I found Scott Hanselman's document here stating that return a DataSet in web service is not a good idea, and there's discussion about the topic on stackoverflow. @StephenBonikowsky base on the information probably the behavior difference is by design when developing features on Core? Need feature owner's further confirm.

[StephenBonikowsky]

Thanks @imcarolwang @dasetser @mconnew Is this a purposeful change between svcutil.exe and dotnet-svcutil.exe?

[dasetser]

This is a purposeful change between svcutil.exe and dotnet-svcutil.exe that was made because dotnet-svcutil was written to support .NET Core 1.0 apps, and these System.Data APIs were not available in 1.0. Now that 1.0 is out of support I believe we could look into supporting these, but I don't think we have time to investigate it for the current release.

[dasetser]

We had another report of this issue on #3932. As part of investigating that developer community issue I looked into this a little more, and it's not as easy as I was thinking it would be. While these System.Data APIs now exist on .NET Core, the way we supported these in wsdl does not. This is still a future work item, but I'll add some notes on it based on my investigation to help when we come back to this.

Essentially what happens is the wsdl declares this as an xs:any element, which could be anything, then puts an annotation in that this is actually a DataSet or DataTable. That's why dotnet-svcutil generates this as a generic type. In the .NET Framework the System.Data code has a custom importer that includes reading this in and correcting the type, and svcutil normally adds that importer so that it works. Unfortunately these importers did not get ported to .NET Core. In order to support this on dotnet-svcutil we would need to port these ourselves, or rewrite a similar importer to detect the annotation and handle it correctly.

[EamonHetherton]

I'm hitting this too. Trying to port some .NET 4.5 code to core 3.1. This code depends on a webservice originally written in .NET 2 that returns typed datasets.

If I create a .NET framework library and "Add Service Reference" it correctly generates the service proxy, but in .NET core using "Add Connected Service" -> "Microsoft WCF Web Service Reference Provider" the service proxy returns System.Xml.XmlElement instead of a dataset. Worse still, this XElement is only the schema part of the result so I can't even manually turn it into a dataset.

Interestingly though, if I replace System.Xml.XmlElement with System.Data.DataSet in the generated code it works. I can live with an untyped dataset, can't use an XmlElement as it is.

I've just done a find->replace of "System.Xml.XmlElement" with "System.Data.DataSet" in Reference.cs for now as this service is simple and all the result types are DataSets and removed the "inputs" section from ConnectedService.json so not one accidently regenerates this.

[jcbvm]

I encountered the same problem a while ago. I'm using the following workaround currently to transform XElements into a DataSet:

private DataSet ToDataSet(ArrayOfXElement data)
{
  DataSet result = new DataSet();
  string rawXml = new XElement("Root", data.Nodes).ToString();
  using (StringReader reader = new StringReader(rawXml))
  {
    result.ReadXml(reader);
  }
  return result;
}

[Peperud]

Just got to this myself, while converting an old project. In my case it is a DataTable being passed as an input parameter.

[Durgagithu]

I am facing similar issue where I need to call webservice which sends and returns Dataset. How can this be resolved?

[eaydemir]

I encountered the same problem a while ago. I'm using the following workaround currently to transform XElements into a DataSet:

private DataSet ToDataSet(ArrayOfXElement data)
{
  DataSet result = new DataSet();
  string rawXml = new XElement("Root", data.Nodes).ToString();
  using (StringReader reader = new StringReader(rawXml))
  {
    result.ReadXml(reader);
  }
  return result;
}

how can we do the opposite? I mean DataSet to ArrayOfXElement.

[Durgagithu]

I encountered the same problem a while ago. I'm using the following workaround currently to transform XElements into a DataSet:

private DataSet ToDataSet(ArrayOfXElement data)
{
  DataSet result = new DataSet();
  string rawXml = new XElement("Root", data.Nodes).ToString();
  using (StringReader reader = new StringReader(rawXml))
  {
    result.ReadXml(reader);
  }
  return result;
}

how can we do the opposite? I mean DataSet to ArrayOfXElement.

I encountered the same problem a while ago. I'm using the following workaround currently to transform XElements into a DataSet:

private DataSet ToDataSet(ArrayOfXElement data)
{
  DataSet result = new DataSet();
  string rawXml = new XElement("Root", data.Nodes).ToString();
  using (StringReader reader = new StringReader(rawXml))
  {
    result.ReadXml(reader);
  }
  return result;
}

how can we do the opposite? I mean DataSet to ArrayOfXElement.

Any luck with this issue?

[PimVendrig]

To convert from DataSet to ArrayOfXElement I am using the following method:

public ArrayOfXElement DataSetToArrayOfXElement(DataSet dataSet)
{
	if (dataSet == null) throw new ArgumentNullException(nameof(dataSet));

	var arrayOfXElement = new ArrayOfXElement();

	using (var schemaStream = new MemoryStream())
	{
		using (var writer = XmlWriter.Create(schemaStream))
		{
			dataSet.WriteXmlSchema(writer);
		}
		schemaStream.Position = 0;
		arrayOfXElement.Nodes.Add(XElement.Load(schemaStream));
	}

	using (var dataStream = new MemoryStream())
	{
		using (var writer = XmlWriter.Create(dataStream))
		{
			dataSet.WriteXml(writer, XmlWriteMode.DiffGram);
		}
		dataStream.Position = 0;
		arrayOfXElement.Nodes.Add(XElement.Load(dataStream));
	}

	return arrayOfXElement;
}

And to convert from ArrayOfXElement to DataSet, I am using:

public DataSet ArrayOfXElementToDataSet(ArrayOfXElement arrayOfXElement)
{
	if (arrayOfXElement == null) throw new ArgumentNullException(nameof(arrayOfXElement));
	if (arrayOfXElement.Nodes.Count != 2) throw new ArgumentException($"{nameof(arrayOfXElement)} should have 2 {nameof(arrayOfXElement.Nodes)}.", nameof(arrayOfXElement));

	var dataSet = new DataSet();

	using (var schemaStream = new MemoryStream())
	{
		using (var writer = XmlWriter.Create(schemaStream))
		{
			arrayOfXElement.Nodes[0].WriteTo(writer);
		}
		schemaStream.Position = 0;
		dataSet.ReadXmlSchema(schemaStream);
	}

	using (var dataStream = new MemoryStream())
	{
		using (var writer = XmlWriter.Create(dataStream))
		{
			arrayOfXElement.Nodes[1].WriteTo(writer);
		}
		dataStream.Position = 0;
		dataSet.ReadXml(dataStream, XmlReadMode.DiffGram);
	}

	return dataSet;
}

[fededim]

I am experiencing the same issue of @sudoudaisuke. The problem is that in the autogenerated code of dotnet-svcutil the XSD referenced by the WSDL with import tag

<s:import schemaLocation="http://xx.yy.zz/ReticaServer/ReticaSara.asmx?schema=EvToAdf" namespace="http://tempuri.org/EvToAdf.xsd"/>
<s:import schemaLocation="http://xx.yy.zz/ReticaServer/ReticaSara.asmx?schema=DefEvento" namespace="http://tempuri.org/DefEvento.xsd"/>
<s:import schemaLocation="http://xx.yy.zz/ReticaServer/ReticaSara.asmx?schema=GestEventi" namespace="http://tempuri.org/EventiInviati.xsd"/>

are not transformed into classes, but they are instead mapped to a generic class composed by 2 properties "XmlElement Any1" and "XmlElement[] Any" which are quite obscure, e.g. I did not find any way to use them (except the sudoudaisuke's suggested workaround). It is a different behaviour from standard .NET svcutil and I would like to know the reasons of this different behaviour (hasn't it been implemented yet ?)

Federico

    public partial class insertAttributiDtInp
    {
        
        private System.Xml.XmlElement[] anyField;
        
        private System.Xml.XmlElement any1Field;
        
        private string namespaceField;
        
        private string tableTypeNameField;
        
        public insertAttributiDtInp()
        {
            this.namespaceField = "http://tempuri.org/DefEvento.xsd";
            this.tableTypeNameField = "ATTRIBUTI_SARADataTable";
        }
        
        /// <remarks/>
        [System.Xml.Serialization.XmlAnyElementAttribute(Namespace="http://www.w3.org/2001/XMLSchema", Order=0)]
        public System.Xml.XmlElement[] Any
        {
            get
            {
                return this.anyField;
            }
            set
            {
                this.anyField = value;
            }
        }
        
        /// <remarks/>
        [System.Xml.Serialization.XmlAnyElementAttribute(Namespace="urn:schemas-microsoft-com:xml-diffgram-v1", Order=1)]
        public System.Xml.XmlElement Any1
        {
            get
            {
                return this.any1Field;
            }
            set
            {
                this.any1Field = value;
            }
        }
        
        /// <remarks/>
        [System.Xml.Serialization.XmlAttributeAttribute()]
        public string @namespace
        {
            get
            {
                return this.namespaceField;
            }
            set
            {
                this.namespaceField = value;
            }
        }
        
        /// <remarks/>
        [System.Xml.Serialization.XmlAttributeAttribute()]
        public string tableTypeName
        {
            get
            {
                return this.tableTypeNameField;
            }
            set
            {
                this.tableTypeNameField = value;
            }
        }
    }

[chucker]

@fededim it's flat-out not implemented in .NET Core. Your best bet is to manually run .NET Framework's version of svcutil instead.

[OronDF343]

Here's my workaround for converting Any and Any1 to DataTable based on the solution from @PimVendrig but with some tweaks. See comment above by @fededim for an example of when to use this. I have not tested reading to DataSet but you should be able to just replace DataTable with DataSet in the code.

    public static DataTable ToDataTable(XmlElement[] any_schema, XmlElement any1_diffGram)
    {
        var dataTable = new DataTable();

        using (var stream = new MemoryStream())
        {
            using (var writer = XmlWriter.Create(stream))
            {
                writer.WriteStartElement("root");
                
                foreach (var item in any_schema)
                    item.WriteTo(writer);
                any1_diffGram.WriteTo(writer);

                writer.WriteEndElement();
            }
            stream.Position = 0;
            dataTable.ReadXml(stream);
        }

        return dataTable;
    }

[moslemkh]

public static DataTable ConvertToDataTable(this XmlElement data) { StringReader theReader = new StringReader(data.InnerXml); DataSet theDataSet = new DataSet(); theDataSet.ReadXml(theReader); return theDataSet.Tables[0];
}