Dimi Dimi -4 years ago 323
C# Question

XML Signature element is not declared

I created XSD using Visual StudioXML Tools. And I use following C# code to validate XML and facing this error.

Error


The element is not declared
'http://www.w3.org/2000/09/xmldsig#:Signature'.


So my question is how to fix it because in edit mode XML is valid 100%?

Thank you!

C#

private void buttonValidateXML_Click(object sender, EventArgs e)
{
try
{
bool result = IsValidXml2(textBoxSignedXML.Text, textBoxXSDFile.Text, "");
rtbValidationResult.Text = result.ToString();
}
catch (Exception ex)
{
rtbValidationResult.Text = ex.Message;
}
}

public static bool IsValidXml2(string xmlFilePath, string xsdFilePath, string namespaceName)
{
var xdoc = XDocument.Load(xmlFilePath);
var schemas = new XmlSchemaSet();
schemas.Add(namespaceName, xsdFilePath);

bool result = true;
xdoc.Validate(schemas, (sender, e) =>
{
result = false;
});

return result;
}


XML

<?xml version="1.0" encoding="utf-8"?>
<Envelope version="1">
<Deposit>
<ClientId>1234567890123</ClientId>
<Account>0045678</Account>
<Currency>USD</Currency>
<Total>5000.00</Total>
<SignedDate>2016-02-15</SignedDate>
<Cheques>
<Cheque>
<Images>
<Front>
SUkqAAgAAAAPAP4ABAABAAAAAAAAAAABBAABAAAAfQUAAAEBBAABAAAAWgIAAAIBAwABAAAAAQAA
AAMBAwABAAAABAAAAAYBAwABAAAAAAAAAA4BAgAhAAAA0AAAABEBBAABAAAAAAIAABIBAwABAAAA
AQAAABUBAwABAAAAAQAAABYBBAABAAAAWgIAABcBBAABAAAAvi8AABoBBQABAAAAAAEAABsBBQAB
EdF0fRG0R0YRdH2R2XzaI6OxRQAQAQA=
</Front>
<Back>
SUkqAAgAAAAOAP4ABAABAAAAAAAAAAABBAABAAAAgQUAAAEBBAABAAAAVAIAAAIBAwABAAAAAQAA
AAMBAwABAAAABAAAAAYBAwABAAAAAAAAABEBBAABAAAAAAEAABIBAwABAAAAAQAAABUBAwABAAAA
AQAAABYBBAABAAAAVAIAABcBBAABAAAAcggAABoBBQABAAAAwAAAABsBBQABAAAA0AAAACgBAwAB
AAAAAgAAAAAAAAAAAAAAAAAAAAAAyAAAAAEAAAAAAAAAAAAAAMgAAAABAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAP//LZCdO1f7iRrKXTqt//pePx///9lNoL487Ajh
jFyzUrtwg+6gg9VmvCIWA42XMwziSUEEw7GoIcSUWZ3Y0oKmGR3LToGVC2LhkK6H4sorQNRUMLjH
LTGzlpv3RFCcH4NLB9hvLTmD8tMgOsG+WVaR5AweTcEWMMfaDQxDIx5NwVQx8OMPeGFHLSUlLcSS
1JtNV/9/rrffuO+h9bx////kfvABABAA
</Back>
</Images>
<MicrCodeCmc>123456789012345678901234567890</MicrCodeCmc>
<Amount>465.22</Amount>
<PaymentDate>2016-02-15</PaymentDate>
<EmissionDate>2016-02-15</EmissionDate>
</Cheque>
<Cheque>
<Images>
<Front>
SUkqAAgAAAAPAP4ABAABAAAAAAAAAAABBAABAAAAfQUAAAEBBAABAAAAWgIAAAIBAwABAAAAAQAA
AAMBAwABAAAABAAAAAYBAwABAAAAAAAAAA4BAgAhAAAA0AAAABEBBAABAAAAAAIAABIBAwABAAAA
AQAAABUBAwABAAAAAQAAABYBBAABAAAAWgIAABcBBAABAAAAvi8AABoBBQABAAAAAAEAABsBBQAB
EdF0fRG0R0YRdH2R2XzaI6OxRQAQAQA=
</Front>
<Back>
SUkqAAgAAAAOAP4ABAABAAAAAAAAAAABBAABAAAAgQUAAAEBBAABAAAAVAIAAAIBAwABAAAAAQAA
AAMBAwABAAAABAAAAAYBAwABAAAAAAAAABEBBAABAAAAAAEAABIBAwABAAAAAQAAABUBAwABAAAA
AQAAABYBBAABAAAAVAIAABcBBAABAAAAcggAABoBBQABAAAAwAAAABsBBQABAAAA0AAAACgBAwAB
AAAAAgAAAAAAAAAAAAAAAAAAAAAAyAAAAAEAAAAAAAAAAAAAAMgAAAABAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAP//LZCdO1f7iRrKXTqt//pePx///9lNoL487Ajh
jFyzUrtwg+6gg9VmvCIWA42XMwziSUEEw7GoIcSUWZ3Y0oKmGR3LToGVC2LhkK6H4sorQNRUMLjH
LTGzlpv3RFCcH4NLB9hvLTmD8tMgOsG+WVaR5AweTcEWMMfaDQxDIx5NwVQx8OMPeGFHLSUlLcSS
1JtNV/9/rrffuO+h9bx////kfvABABAA
</Back>
</Images>
<MicrCodeCmc>123456789012345678901234567890</MicrCodeCmc>
<Amount>99999999999</Amount>
<PaymentDate>2016-02-15</PaymentDate>
<EmissionDate>2016-02-15</EmissionDate>
</Cheque>
</Cheques>
</Deposit>
<Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
<SignedInfo>
<CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315" />
<SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" />
<Reference URI="">
<Transforms>
<Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
</Transforms>
<DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
<DigestValue>TVO2Gssf5TUdXFYG/PrHDyqYFqs=</DigestValue>
</Reference>
</SignedInfo>
<SignatureValue>KwQInN03ywa0u0t4HedxgE1fOU7XYLQScKuQ6vdYoIZME5Hm5jpFeX2ORA2U+BO7JNjmFilTW05VntS3k98YCZhNXH9Iw/YEC1nw4JJLzygYbbCftkiY5v5+b494mQPryCtscwTtbziW6QilILSFDGmco2JopRfVe+qfdN/JyB1HXhUfApyNEsw/cJLj6aaz5ivN1sLFgAlikbwCNpF+mRnZY5u7/S8uT8WhEyK32EcatdjzKbP0PwnIlumhOpUMerWeLZ7neuJq6R/IuFgZ1Y5U6ppyuOjhtiHp4glC/uNUS/y7jMzG29thWBkEtSE9AcEt2IZ0HOEZE3kdFXufjA==</SignatureValue>
</Signature>
</Envelope>


XSD

<?xml version="1.0" encoding="utf-8"?>
<xs:schema attributeFormDefault="unqualified" elementFormDefault="qualified" xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:tns="http://example.com/ct-required"
xmlns:xmime="http://www.w3.org/2005/05/xmlmime" >

<xs:import namespace="http://www.w3.org/2005/05/xmlmime"
schemaLocation="http://www.w3.org/2005/05/xmlmime"/>

<xs:import namespace="http://www.w3.org/2000/09/xmldsig#" schemaLocation="xmldsig-core-schema.xsd"/>

<xs:simpleType name="PNGPictureType"
xmime:expectedContentTypes="image/png">
<xs:restriction base="xs:base64Binary"/>
</xs:simpleType>

<xs:simpleType name="Money">
<xs:restriction base="xs:decimal">
<xs:totalDigits value="13" />
<xs:fractionDigits value="2" />
<xs:minInclusive value="0.00" />
<xs:maxInclusive value="99999999999.99" />
</xs:restriction>
</xs:simpleType>

<xs:simpleType name="Currency">
<xs:annotation>
<xs:documentation>Currency Code: ISO 4217</xs:documentation>
</xs:annotation>
<xs:restriction base="xs:string">
<xs:enumeration value="USD" />
<xs:enumeration value="UYU" />
<xs:minLength value="3" />
<xs:maxLength value="3" />
</xs:restriction>
</xs:simpleType>

<xs:element name="Envelope">
<xs:complexType>
<xs:sequence>
<xs:element name="Deposit" minOccurs="1" maxOccurs="1">
<xs:complexType>
<xs:sequence>
<xs:element name="ClientId" type="xs:unsignedLong" />
<xs:element name="Account" type="xs:unsignedLong" />
<xs:element name="Currency" type="Currency" />
<xs:element name="Total" type="Money" />
<xs:element name="SignedDate" type="xs:date" />
<xs:element name="Cheques">
<xs:complexType>
<xs:sequence>
<xs:element maxOccurs="unbounded" name="Cheque">
<xs:complexType>
<xs:sequence>
<xs:element name="Images">
<xs:complexType>
<xs:sequence>
<xs:element name="Front" type="PNGPictureType" />
<xs:element name="Back" type="PNGPictureType" />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="MicrCodeCmc" type="xs:string" />
<xs:element name="Amount" type="Money" />
<xs:element name="PaymentDate" type="xs:date" />
<xs:element name="EmissionDate" type="xs:date" />
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element xmlns:q1="http://www.w3.org/2000/09/xmldsig#" ref="q1:Signature" />
</xs:sequence>
<xs:attribute name="version" type="xs:unsignedByte" use="required" />
</xs:complexType>
</xs:element>
</xs:schema>


UPDATE #1

I have tried different approaches but no joy.

enter image description here

And even if I reference XSD to local file it does not work. I see the same error.

<xs:import namespace="http://www.w3.org/2000/09/xmldsig#" schemaLocation="http://www.w3.org/TR/2002/REC-xmldsig-core-20020212 file:///C:/Temp/xmldsig-core-schema.xsd"/>


UPDATE #2

Even I use this approach no joy.

public static bool IsValidXml1(string xmlFilePath, string xsdFilePath, string namespaceName)
{
XDocument xdoc = null;
var settings = new XmlReaderSettings();
settings.DtdProcessing = DtdProcessing.Ignore;
settings.ProhibitDtd = false;

try
{
using (XmlReader xr = XmlReader.Create(xmlFilePath, settings))
{
xdoc = XDocument.Load(xr);
var schemas = new XmlSchemaSet();
schemas.Add(namespaceName, xsdFilePath);
schemas.Add(@"http://www.w3.org/2000/09/xmldsig#", @"D:\Temp\xmldsig-core-schema.xsd");
xdoc.Validate(schemas, null);

return true;
}
}
catch (XmlSchemaValidationException ex)
{
// throw;
}

return false;
}

Answer Source

If you don't want to change anything to xsd or xml - do the following:

  1. (optional) Download xsd from w3 site and save to local disk. W3 site is VERY slow because a lot of software worldwide constantly request those schemas. If you will use that xsd directly - you will often fail by timeout. Some validation tools already have such schemas cached locally, but not .NET validator.

  2. Modify your validation method from UPDATE 2 the following way:

    public static bool IsValidXml1(string xmlFilePath, string xsdFilePath, string namespaceName)
    {
        XDocument xdoc = null;
        var settings = new XmlReaderSettings();
        settings.DtdProcessing = DtdProcessing.Ignore;
    
        try
        {
            using (XmlReader xr = XmlReader.Create(xmlFilePath, settings))
            {
                xdoc = XDocument.Load(xr);
                var schemas = new XmlSchemaSet();                    
                schemas.Add(namespaceName, xsdFilePath);                   
                using (var fs = File.OpenRead(@"D:\Temp\xmldsig-core-schema.xsd")) 
                using (var reader = XmlReader.Create(fs, new XmlReaderSettings() {
                    DtdProcessing = DtdProcessing.Ignore // important
                })) {
                    schemas.Add(@"http://www.w3.org/2000/09/xmldsig#", reader);
                }
    
                xdoc.Validate(schemas, null);
    
                return true;
            }
        }
        catch (XmlSchemaValidationException ex)
        {
            // throw;
        }
    
        return false;
    }
    

You have to add that schema using XmlReader and not directly, because if you add directly (like in your update 2) - it will fail to parse DTD block, because when you add XmlSchema to XmlSchemaSet using url (or file path) - it will read that file using XmlReaderSettings with DtdProcessing = DtdProcessing.Prohibit. We need to change that to DtdProcessing.Ignore or DtdProcessing.Parse. After that your validation method will work fine for target xsd and xml file, without any changes (and will correctly fail in case xml does not match xsd).

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