C# XmlWriter赢得'；无法正确生成所需的名称空间

我正在尝试生成与此格式匹配的XML数据：

<samlp:AuthnRequest
        xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
        xmlns="urn:oasis:names:tc:SAML:2.0:assertion"
        IssueInstant="2018-07-04T19:19:53.284Z"
        ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST"
        Version="2.0">
    <samlp:NameIDPolicy
            AllowCreate="true"
            Format="urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified"/>
</samlp:AuthnRequest>

以下是我的一些尝试和结果

尝试#1

结果#1

与上述消息一起崩溃。

尝试#2

结果#2

要么没有出现，要么是错误的

---

为了按需要的方式生成它，我无法找出我缺少的内容。

以下代码可以正常工作并成功编写所需的XML：

var issueInstant = DateTime.Parse("2018-07-04T19:19:53.284Z", CultureInfo.InvariantCulture);

using (var xw = XmlWriter.Create(sw, xws))
{
    var samplNs = "urn:oasis:names:tc:SAML:2.0:protocol";
    var defaultNs = "urn:oasis:names:tc:SAML:2.0:assertion";

    // XmlWriter.WriteStartElement(String prefix, String localName, String ns)
    xw.WriteStartElement("samlp", "AuthnRequest", samplNs);

    // Write the xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol" namespace.
    // Actually this is redundant as the attribute will be automatically be written at the end of the
    // attribute list do to the previous call to xw.WriteStartElement().  Call it here only if, for some
    // reason, you need to control the attribute order.
    xw.WriteAttributeString("xmlns", "samlp", null, samplNs);               

    // Write the default namespace
    xw.WriteAttributeString("xmlns", defaultNs);

    // Write attribute values.              
    xw.WriteAttributeString("IssueInstant", XmlConvert.ToString(issueInstant, XmlDateTimeSerializationMode.Utc));
    xw.WriteAttributeString("ProtocolBinding", "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST");
    xw.WriteAttributeString("Version", "2.0");

    // Write samlp:NameIDPolicy
    // No need to specify prefix since it is specified in the document root.
    xw.WriteStartElement("NameIDPolicy", samplNs);
    xw.WriteAttributeString("AllowCreate", XmlConvert.ToString(true));
    xw.WriteAttributeString("Format", "urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified");

    // Write the end of NameIDPolicy
    xw.WriteEndElement();

    // Write the end of AuthnRequest
    xw.WriteEndElement();
}       

注:

• 该方法将名称空间作为第二个参数，但您传递的是名称空间前缀

  “samlp”

  。所以那没用

• 但是打电话

  xw.WriteStartElement("AuthnRequest", "urn:oasis:names:tc:SAML:2.0:protocol"); 
  

  也会失败，因为这样做会将“urn:oasis:names:tc:SAML:2.0:protocol”建立为默认名称空间，而您希望它是前缀为

  sampl

  的非默认名称空间。因此必须使用

• 使用指定的名称空间和名称空间前缀显式地编写了

  AuthnRequest

  元素后，实际上不再需要再编写名称空间属性--

  XmlWriter

  将在属性列表的末尾自动为您编写。如果要控制名称空间属性在属性列表中的位置，只需手动编写名称空间属性。然而，根据该报告：
  请注意，属性规范在开始标记或空元素标记中的顺序并不重要
  所以，你可以跳过这个

• 类中的方法可用于将非字符串原语从XML正确转换为XML

---

这里的fiddle示例：。

我发现，当您有复杂的名称空间时，只解析字符串要容易得多。使用xml linq：

            string xml =
                "<samlp:AuthnRequest" +
                    " xmlns:samlp=\"urn:oasis:names:tc:SAML:2.0:protocol\"" +
                    " xmlns=\"urn:oasis:names:tc:SAML:2.0:assertion\"" +
                    " IssueInstant=\"2018-07-04T19:19:53.284Z\"" +
                    " ProtocolBinding=\"urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST\"" +
                    " Version=\"2.0\">" +
                    "<samlp:NameIDPolicy" +
                       " AllowCreate=\"true\"" +
                       " Format=\"urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified\"/>" +
                "</samlp:AuthnRequest>";

            XDocument doc = XDocument.Parse(xml);

stringxml=
"" +
"" +
"";
XDocument doc=XDocument.Parse（xml）；

<AuthnRequest
    xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"
    ForceAuthn="false" ID="ID_4f85b6d1-a839-4899-972c-12275bf8711c"
    IssueInstant="2018-08-15T18:23:49Z"
    ProtocolBinding="urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST"
    Version="2.0"
    xmlns="samlp">
    ...

xmlns="urn:oasis:names:tc:SAML:2.0:assertion"

var issueInstant = DateTime.Parse("2018-07-04T19:19:53.284Z", CultureInfo.InvariantCulture);

using (var xw = XmlWriter.Create(sw, xws))
{
    var samplNs = "urn:oasis:names:tc:SAML:2.0:protocol";
    var defaultNs = "urn:oasis:names:tc:SAML:2.0:assertion";

    // XmlWriter.WriteStartElement(String prefix, String localName, String ns)
    xw.WriteStartElement("samlp", "AuthnRequest", samplNs);

    // Write the xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol" namespace.
    // Actually this is redundant as the attribute will be automatically be written at the end of the
    // attribute list do to the previous call to xw.WriteStartElement().  Call it here only if, for some
    // reason, you need to control the attribute order.
    xw.WriteAttributeString("xmlns", "samlp", null, samplNs);               

    // Write the default namespace
    xw.WriteAttributeString("xmlns", defaultNs);

    // Write attribute values.              
    xw.WriteAttributeString("IssueInstant", XmlConvert.ToString(issueInstant, XmlDateTimeSerializationMode.Utc));
    xw.WriteAttributeString("ProtocolBinding", "urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST");
    xw.WriteAttributeString("Version", "2.0");

    // Write samlp:NameIDPolicy
    // No need to specify prefix since it is specified in the document root.
    xw.WriteStartElement("NameIDPolicy", samplNs);
    xw.WriteAttributeString("AllowCreate", XmlConvert.ToString(true));
    xw.WriteAttributeString("Format", "urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified");

    // Write the end of NameIDPolicy
    xw.WriteEndElement();

    // Write the end of AuthnRequest
    xw.WriteEndElement();
}       

xw.WriteStartElement("AuthnRequest", "urn:oasis:names:tc:SAML:2.0:protocol"); 

            string xml =
                "<samlp:AuthnRequest" +
                    " xmlns:samlp=\"urn:oasis:names:tc:SAML:2.0:protocol\"" +
                    " xmlns=\"urn:oasis:names:tc:SAML:2.0:assertion\"" +
                    " IssueInstant=\"2018-07-04T19:19:53.284Z\"" +
                    " ProtocolBinding=\"urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST\"" +
                    " Version=\"2.0\">" +
                    "<samlp:NameIDPolicy" +
                       " AllowCreate=\"true\"" +
                       " Format=\"urn:oasis:names:tc:SAML:1.1:nameid-format:unspecified\"/>" +
                "</samlp:AuthnRequest>";

            XDocument doc = XDocument.Parse(xml);