ArcGIS Pro 2.8 API Reference Guide
SetXml Method (Item)
Example 

ArcGIS.Desktop.Core Namespace > Item Class : SetXml Method
Sets the item’s metadata to the XML document provided as a string. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public void SetXml( 
   string xml
)
Public Sub SetXml( _
   ByVal xml As String _
) 

Parameters

xml

Return Value

void
Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
The metadata for this item cannot be edited
Remarks
Existing metadata is replaced. Metadata is created for the item if it doesn't already exist.
Example
await QueuedTask.Run(() =>
{
  var xml = System.IO.File.ReadAllText(@"E:\Data\Metadata\MetadataForFeatClass.xml");
  //Will throw InvalidOperationException if the metadata cannot be changed
  //so check "CanEdit" first
  if (featureClassMetadataItem.CanEdit())
    featureClassMetadataItem.SetXml(xml);
});
     
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

Item Class
Item Members