update XML IO pattern.

App/wwwroot/HiAPI-docsite/sample/Sample.MachineTool.DemoBuildMachineTool.html

@@ -180,9 +180,15 @@ namespace Sample.MachineTool
     /// </remarks>
     public class DemoBuildMachineTool : IGetCodeXyzabcMachineTool
     {
-        static DemoBuildMachineTool()
+        /// <summary>
+        /// Registers this type's deserializer with the given <see cref="XFactory"/>
+        /// (or <see cref="XFactory.Default"/> when <paramref name="factory"/> is
+        /// <c>null</c>). Idempotent.
+        /// </summary>
+        public static void Reg(XFactory factory = null)
         {
-            XFactory.Generators.Add(XName, (xml, baseDirectory, relFile, progress, res) => new DemoBuildMachineTool());
+            factory ??= XFactory.Default;
+            factory.Generators.TryAdd(XName, (xml, baseDirectory, relFile, progress, res) => new DemoBuildMachineTool());
         }
         /// <summary>
         /// Generates an XYZ-ABC machine tool instance from embedded resources.
@@ -409,6 +415,40 @@ namespace Sample.MachineTool
 
 
 
+  <a id="Sample_MachineTool_DemoBuildMachineTool_Reg_" data-uid="Sample.MachineTool.DemoBuildMachineTool.Reg*"></a>
+
+  <h3 id="Sample_MachineTool_DemoBuildMachineTool_Reg_Hi_Common_XmlUtils_XFactory_" data-uid="Sample.MachineTool.DemoBuildMachineTool.Reg(Hi.Common.XmlUtils.XFactory)">
+  Reg(XFactory)
+  
+  </h3>
+
+  <div class="markdown level1 summary"><p>Registers this type's deserializer with the given <a class="xref" href="../api/Hi.Common.XmlUtils.XFactory.html">XFactory</a>
+(or <a class="xref" href="../api/Hi.Common.XmlUtils.XFactory.html#Hi_Common_XmlUtils_XFactory_Default">Default</a> when <code class="paramref">factory</code> is
+<code>null</code>). Idempotent.</p>
+</div>
+  <div class="markdown level1 conceptual"></div>
+
+  <div class="codewrapper">
+    <pre><code class="lang-csharp hljs">public static void Reg(XFactory factory = null)</code></pre>
+  </div>
+
+  <h4 class="section">Parameters</h4>
+  <dl class="parameters">
+    <dt><code>factory</code> <a class="xref" href="../api/Hi.Common.XmlUtils.XFactory.html">XFactory</a></dt>
+    <dd></dd>
+  </dl>
+
+
+
+
+
+
+
+
+
+
+
+
   <a id="Sample_MachineTool_DemoBuildMachineTool_ToXElement_" data-uid="Sample.MachineTool.DemoBuildMachineTool.ToXElement*"></a>
 
   <h3 id="Sample_MachineTool_DemoBuildMachineTool_ToXElement" data-uid="Sample.MachineTool.DemoBuildMachineTool.ToXElement">