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Can't deserialize xml with element starting with 'μ'

I have an xml config file:

<Instruments>
  <Instrument Name="uEyeFF1" Assembly="Instruments" Class="IDSuEye1240SE">
    <Settings>
      <IDSuEye1240SESettings>
        <Serial>4102801225</Serial>
        <µmPerPixel>5.3</µmPerPixel>
        <Color>true</Color>
      </IDSuEye1240SESettings>
    </Settings>
  </Instrument>
  <!-- more Instruments -->
</Instruments>

and the class for which <IDSuEye1240SESettings>

node is being deserialized :

[Serializable]
public class IDSuEye1240SESettings
{
    [XmlElement]
    public string Serial { get; set; }
    [XmlElement]
    public double µmPerPixel { get; set; }
    [XmlElement]
    public bool Color { get; set; }
}

But when deserializing, I get the following error:

'There is an error in the XML document (69, 10). in Utilities.Load () as System.Void
at path hidden 'Name cannot start with character' μ ', hex value 0xB5. Line 69, position 10. 'in System.Xml.Throw () as System.Void Remainder of the stack trace ...

Another PC is running an earlier compiled version of the same application and I am apparently able to deserialize the xml for the class. But the developer who wrote it doesn't exist.

As far as I know, the working code doing deserialization should be the same as the current code:

// the <Settings> node children is value below
_settings = ConvertNode<IDSuEye1240SESettings>(((XmlNode[])value).First())

public T ConvertNode<T>(XmlNode node)
{
    MemoryStream ms = new MemoryStream();
    StreamWriter sw = new StreamWriter(ms);
    sw.Write(node.OuterXml);
    sw.Flush();
    ms.Position = 0;
    XmlSerializer ser = new XmlSerializer(typeof(T));
    T result = (T)ser.Deserialize(ms);
    return result;
}

Is it possible that there is something else in the compiled code that works to allow the "μ" character to start the xml element name?

I found the difference in the first line of xml files between PCs:

IN:

<?xml version="1.0"?>
<Instruments
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
  xsi:schemaLocation="http://www.w3schools.com Instruments.xsd">

Does not work:

<?xml version="1.0" encoding="utf-8"?>
<Instruments 
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
  xmlns:xsd="http://www.w3.org/2001/XMLSchema" 
  xsi:schemaLocation="http://www.w3schools.com Instruments.xsd">

But I removed the encoding attribute, but only removed the red underline below "μ" for the new file opened in the IDE. This did not solve the serialization issue.

The schematic files are identical for both PCs, if that matters.

Can an illegal character be allowed to run xml node?

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1 answer


I have decompiled System.Xml to see why this exception might be thrown, and I think I found the answer ...

Shorter

There is no way to hack into it. But you can solve your problem without changing the XML.

In the long

Unfotunetly XML 5th edition is significantly different in defining the symbols that can be used to trigger tag names. Here are the decompiled constants from System.Xml that prove my point:

#if XML10_FIFTH_EDITION
        // StartNameChar without ':' -- see Section 2.3 production [4]
        const string s_NCStartName =
            "\u0041\u005a\u005f\u005f\u0061\u007a\u00c0\u00d6" +
            "\u00d8\u00f6\u00f8\u02ff\u0370\u037d\u037f\u1fff" +
            "\u200c\u200d\u2070\u218f\u2c00\u2fef\u3001\ud7ff" +
            "\uf900\ufdcf\ufdf0\ufffd";

        // NameChar without ':' -- see Section 2.3 production [4a] 
        const string s_NCName =
            "\u002d\u002e\u0030\u0039\u0041\u005a\u005f\u005f" +
            "\u0061\u007a\u00b7\u00b7\u00c0\u00d6\u00d8\u00f6" +
            "\u00f8\u037d\u037f\u1fff\u200c\u200d\u203f\u2040" +
            "\u2070\u218f\u2c00\u2fef\u3001\ud7ff\uf900\ufdcf" +
            "\ufdf0\ufffd";
#else
        const string s_NCStartName =
            "\u0041\u005a\u005f\u005f\u0061\u007a" +
            "\u00c0\u00d6\u00d8\u00f6\u00f8\u0131\u0134\u013e" +
            "\u0141\u0148\u014a\u017e\u0180\u01c3\u01cd\u01f0" +
            "\u01f4\u01f5\u01fa\u0217\u0250\u02a8\u02bb\u02c1" +
            "\u0386\u0386\u0388\u038a\u038c\u038c\u038e\u03a1" +
            "\u03a3\u03ce\u03d0\u03d6\u03da\u03da\u03dc\u03dc" +
            "\u03de\u03de\u03e0\u03e0\u03e2\u03f3\u0401\u040c" +
            "\u040e\u044f\u0451\u045c\u045e\u0481\u0490\u04c4" +
            "\u04c7\u04c8\u04cb\u04cc\u04d0\u04eb\u04ee\u04f5" +
            "\u04f8\u04f9\u0531\u0556\u0559\u0559\u0561\u0586" +
            "\u05d0\u05ea\u05f0\u05f2\u0621\u063a\u0641\u064a" +
            "\u0671\u06b7\u06ba\u06be\u06c0\u06ce\u06d0\u06d3" +
            "\u06d5\u06d5\u06e5\u06e6\u0905\u0939\u093d\u093d" +
            "\u0958\u0961\u0985\u098c\u098f\u0990\u0993\u09a8" +
            "\u09aa\u09b0\u09b2\u09b2\u09b6\u09b9\u09dc\u09dd" +
            "\u09df\u09e1\u09f0\u09f1\u0a05\u0a0a\u0a0f\u0a10" +
            "\u0a13\u0a28\u0a2a\u0a30\u0a32\u0a33\u0a35\u0a36" +
            "\u0a38\u0a39\u0a59\u0a5c\u0a5e\u0a5e\u0a72\u0a74" +
            "\u0a85\u0a8b\u0a8d\u0a8d\u0a8f\u0a91\u0a93\u0aa8" +
            "\u0aaa\u0ab0\u0ab2\u0ab3\u0ab5\u0ab9\u0abd\u0abd" +
            "\u0ae0\u0ae0\u0b05\u0b0c\u0b0f\u0b10\u0b13\u0b28" +
            "\u0b2a\u0b30\u0b32\u0b33\u0b36\u0b39\u0b3d\u0b3d" +
            "\u0b5c\u0b5d\u0b5f\u0b61\u0b85\u0b8a\u0b8e\u0b90" +
            "\u0b92\u0b95\u0b99\u0b9a\u0b9c\u0b9c\u0b9e\u0b9f" +
            "\u0ba3\u0ba4\u0ba8\u0baa\u0bae\u0bb5\u0bb7\u0bb9" +
            "\u0c05\u0c0c\u0c0e\u0c10\u0c12\u0c28\u0c2a\u0c33" +
            "\u0c35\u0c39\u0c60\u0c61\u0c85\u0c8c\u0c8e\u0c90" +
            "\u0c92\u0ca8\u0caa\u0cb3\u0cb5\u0cb9\u0cde\u0cde" +
            "\u0ce0\u0ce1\u0d05\u0d0c\u0d0e\u0d10\u0d12\u0d28" +
            "\u0d2a\u0d39\u0d60\u0d61\u0e01\u0e2e\u0e30\u0e30" +
            "\u0e32\u0e33\u0e40\u0e45\u0e81\u0e82\u0e84\u0e84" +
            "\u0e87\u0e88\u0e8a\u0e8a\u0e8d\u0e8d\u0e94\u0e97" +
            "\u0e99\u0e9f\u0ea1\u0ea3\u0ea5\u0ea5\u0ea7\u0ea7" +
            "\u0eaa\u0eab\u0ead\u0eae\u0eb0\u0eb0\u0eb2\u0eb3" +
            "\u0ebd\u0ebd\u0ec0\u0ec4\u0f40\u0f47\u0f49\u0f69" +
            "\u10a0\u10c5\u10d0\u10f6\u1100\u1100\u1102\u1103" +
            "\u1105\u1107\u1109\u1109\u110b\u110c\u110e\u1112" +
            "\u113c\u113c\u113e\u113e\u1140\u1140\u114c\u114c" +
            "\u114e\u114e\u1150\u1150\u1154\u1155\u1159\u1159" +
            "\u115f\u1161\u1163\u1163\u1165\u1165\u1167\u1167" +
            "\u1169\u1169\u116d\u116e\u1172\u1173\u1175\u1175" +
            "\u119e\u119e\u11a8\u11a8\u11ab\u11ab\u11ae\u11af" +
            "\u11b7\u11b8\u11ba\u11ba\u11bc\u11c2\u11eb\u11eb" +
            "\u11f0\u11f0\u11f9\u11f9\u1e00\u1e9b\u1ea0\u1ef9" +
            "\u1f00\u1f15\u1f18\u1f1d\u1f20\u1f45\u1f48\u1f4d" +
            "\u1f50\u1f57\u1f59\u1f59\u1f5b\u1f5b\u1f5d\u1f5d" +
            "\u1f5f\u1f7d\u1f80\u1fb4\u1fb6\u1fbc\u1fbe\u1fbe" +
            "\u1fc2\u1fc4\u1fc6\u1fcc\u1fd0\u1fd3\u1fd6\u1fdb" +
            "\u1fe0\u1fec\u1ff2\u1ff4\u1ff6\u1ffc\u2126\u2126" +
            "\u212a\u212b\u212e\u212e\u2180\u2182\u3007\u3007" +
            "\u3021\u3029\u3041\u3094\u30a1\u30fa\u3105\u312c" +
            "\u4e00\u9fa5\uac00\ud7a3";

        const string s_NCName =
            "\u002d\u002e\u0030\u0039\u0041\u005a\u005f\u005f" +
            "\u0061\u007a\u00b7\u00b7\u00c0\u00d6\u00d8\u00f6" +
            "\u00f8\u0131\u0134\u013e\u0141\u0148\u014a\u017e" +
            "\u0180\u01c3\u01cd\u01f0\u01f4\u01f5\u01fa\u0217" +
            "\u0250\u02a8\u02bb\u02c1\u02d0\u02d1\u0300\u0345" +
            "\u0360\u0361\u0386\u038a\u038c\u038c\u038e\u03a1" +
            "\u03a3\u03ce\u03d0\u03d6\u03da\u03da\u03dc\u03dc" +
            "\u03de\u03de\u03e0\u03e0\u03e2\u03f3\u0401\u040c" +
            "\u040e\u044f\u0451\u045c\u045e\u0481\u0483\u0486" +   
            "\u0490\u04c4\u04c7\u04c8\u04cb\u04cc\u04d0\u04eb" +  
            "\u04ee\u04f5\u04f8\u04f9\u0531\u0556\u0559\u0559" +
            "\u0561\u0586\u0591\u05a1\u05a3\u05b9\u05bb\u05bd" +
            "\u05bf\u05bf\u05c1\u05c2\u05c4\u05c4\u05d0\u05ea" +
            "\u05f0\u05f2\u0621\u063a\u0640\u0652\u0660\u0669" +
            "\u0670\u06b7\u06ba\u06be\u06c0\u06ce\u06d0\u06d3" +
            "\u06d5\u06e8\u06ea\u06ed\u06f0\u06f9\u0901\u0903" +
            "\u0905\u0939\u093c\u094d\u0951\u0954\u0958\u0963" +
            "\u0966\u096f\u0981\u0983\u0985\u098c\u098f\u0990" +
            "\u0993\u09a8\u09aa\u09b0\u09b2\u09b2\u09b6\u09b9" +
            "\u09bc\u09bc\u09be\u09c4\u09c7\u09c8\u09cb\u09cd" +
            "\u09d7\u09d7\u09dc\u09dd\u09df\u09e3\u09e6\u09f1" +
            "\u0a02\u0a02\u0a05\u0a0a\u0a0f\u0a10\u0a13\u0a28" +
            "\u0a2a\u0a30\u0a32\u0a33\u0a35\u0a36\u0a38\u0a39" +
            "\u0a3c\u0a3c\u0a3e\u0a42\u0a47\u0a48\u0a4b\u0a4d" +
            "\u0a59\u0a5c\u0a5e\u0a5e\u0a66\u0a74\u0a81\u0a83" +
            "\u0a85\u0a8b\u0a8d\u0a8d\u0a8f\u0a91\u0a93\u0aa8" +
            "\u0aaa\u0ab0\u0ab2\u0ab3\u0ab5\u0ab9\u0abc\u0ac5" +
            "\u0ac7\u0ac9\u0acb\u0acd\u0ae0\u0ae0\u0ae6\u0aef" +
            "\u0b01\u0b03\u0b05\u0b0c\u0b0f\u0b10\u0b13\u0b28" +
            "\u0b2a\u0b30\u0b32\u0b33\u0b36\u0b39\u0b3c\u0b43" +
            "\u0b47\u0b48\u0b4b\u0b4d\u0b56\u0b57\u0b5c\u0b5d" +
            "\u0b5f\u0b61\u0b66\u0b6f\u0b82\u0b83\u0b85\u0b8a" +
            "\u0b8e\u0b90\u0b92\u0b95\u0b99\u0b9a\u0b9c\u0b9c" +
            "\u0b9e\u0b9f\u0ba3\u0ba4\u0ba8\u0baa\u0bae\u0bb5" +
            "\u0bb7\u0bb9\u0bbe\u0bc2\u0bc6\u0bc8\u0bca\u0bcd" +
            "\u0bd7\u0bd7\u0be7\u0bef\u0c01\u0c03\u0c05\u0c0c" +
            "\u0c0e\u0c10\u0c12\u0c28\u0c2a\u0c33\u0c35\u0c39" +
            "\u0c3e\u0c44\u0c46\u0c48\u0c4a\u0c4d\u0c55\u0c56" +
            "\u0c60\u0c61\u0c66\u0c6f\u0c82\u0c83\u0c85\u0c8c" +
            "\u0c8e\u0c90\u0c92\u0ca8\u0caa\u0cb3\u0cb5\u0cb9" +
            "\u0cbe\u0cc4\u0cc6\u0cc8\u0cca\u0ccd\u0cd5\u0cd6" +
            "\u0cde\u0cde\u0ce0\u0ce1\u0ce6\u0cef\u0d02\u0d03" +
            "\u0d05\u0d0c\u0d0e\u0d10\u0d12\u0d28\u0d2a\u0d39" +
            "\u0d3e\u0d43\u0d46\u0d48\u0d4a\u0d4d\u0d57\u0d57" +
            "\u0d60\u0d61\u0d66\u0d6f\u0e01\u0e2e\u0e30\u0e3a" +
            "\u0e40\u0e4e\u0e50\u0e59\u0e81\u0e82\u0e84\u0e84" +
            "\u0e87\u0e88\u0e8a\u0e8a\u0e8d\u0e8d\u0e94\u0e97" +
            "\u0e99\u0e9f\u0ea1\u0ea3\u0ea5\u0ea5\u0ea7\u0ea7" +
            "\u0eaa\u0eab\u0ead\u0eae\u0eb0\u0eb9\u0ebb\u0ebd" +
            "\u0ec0\u0ec4\u0ec6\u0ec6\u0ec8\u0ecd\u0ed0\u0ed9" +
            "\u0f18\u0f19\u0f20\u0f29\u0f35\u0f35\u0f37\u0f37" +
            "\u0f39\u0f39\u0f3e\u0f47\u0f49\u0f69\u0f71\u0f84" +
            "\u0f86\u0f8b\u0f90\u0f95\u0f97\u0f97\u0f99\u0fad" +
            "\u0fb1\u0fb7\u0fb9\u0fb9\u10a0\u10c5\u10d0\u10f6" +
            "\u1100\u1100\u1102\u1103\u1105\u1107\u1109\u1109" +
            "\u110b\u110c\u110e\u1112\u113c\u113c\u113e\u113e" +
            "\u1140\u1140\u114c\u114c\u114e\u114e\u1150\u1150" +
            "\u1154\u1155\u1159\u1159\u115f\u1161\u1163\u1163" +
            "\u1165\u1165\u1167\u1167\u1169\u1169\u116d\u116e" +
            "\u1172\u1173\u1175\u1175\u119e\u119e\u11a8\u11a8" +
            "\u11ab\u11ab\u11ae\u11af\u11b7\u11b8\u11ba\u11ba" +
            "\u11bc\u11c2\u11eb\u11eb\u11f0\u11f0\u11f9\u11f9" +
            "\u1e00\u1e9b\u1ea0\u1ef9\u1f00\u1f15\u1f18\u1f1d" +
            "\u1f20\u1f45\u1f48\u1f4d\u1f50\u1f57\u1f59\u1f59" +
            "\u1f5b\u1f5b\u1f5d\u1f5d\u1f5f\u1f7d\u1f80\u1fb4" +
            "\u1fb6\u1fbc\u1fbe\u1fbe\u1fc2\u1fc4\u1fc6\u1fcc" +
            "\u1fd0\u1fd3\u1fd6\u1fdb\u1fe0\u1fec\u1ff2\u1ff4" +
            "\u1ff6\u1ffc\u20d0\u20dc\u20e1\u20e1\u2126\u2126" +
            "\u212a\u212b\u212e\u212e\u2180\u2182\u3005\u3005" +
            "\u3007\u3007\u3021\u302f\u3031\u3035\u3041\u3094" +
            "\u3099\u309a\u309d\u309e\u30a1\u30fa\u30fc\u30fe" +
            "\u3105\u312c\u4e00\u9fa5\uac00\ud7a3";
#endif

What is the cause of your problem: the s_NCStartName constant defines what characters can be used to start your name, and in the fifth release it is VERY short (you won't find 0xB5 on a new line) and there is no way to get around this. It's permanently, hardcoded into System.Xml. Well, this is Microsoft, they don't need backward compatibility.



As for the solution

You have four options:

  • Attach the old System.Xml which is worse in my opinion but simpler.
  • Provides your xml: strip it from invalid initial name characters.
  • Blame Microsoft for keeping track of issues about this: loss of backward compatibility.
  • Use other frameworks for serialization like Xml.Net

PS

A little advice. You can rewrite ConvertNode like this:

    public static T ConvertNode<T>(XmlNode node)
    {
        using (var reader = new XmlNodeReader(node))
        {
            var ser = new XmlSerializer(typeof(T));
            return (T) ser.Deserialize(reader);
        }
    }
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