How to create an attribute with specific value if it doesn't exist - VBA - excel

Question

Sorry for my bad English, but i'll try to describe my problem right. I have a code in VBA. Here it is:
Sub TestXML()
Dim doc As New DOMDocument
Const filePath As String = "D:\Test3.xml"
Dim isLoaded As Boolean
isLoaded = doc.Load(filePath)
If isLoaded Then
Dim oAttributes As MSXML2.IXMLDOMNodeList
Set oAttributes = doc.getElementsByTagName("Operation")
Dim attr As MSXML2.IXMLDOMAttribute
Dim node As MSXML2.IXMLDOMElement
Dim tdate As String
tdate = Format(Now(), "yyyy-mm-dd")
For Each node In oAttributes
For Each attr In node.Attributes
If attr.Name = "Client" Then
If attr.Value <> "UL" Then
attr.Value = "UL"
End If
ElseIf attr.Name = "Date" Then
If attr.Value <> "tdate" Then
attr.Value = tdate
End If
End If
Next attr
Next node
doc.Save filePath
End If
End Sub
Question is - How can i create attribute "Client" with value "UL" in element "Operation" only if it doesn't exist?
Here is a .xml file example with which i working:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Document>
<Operations>
<Operation Date="2018-11-06" Client="UL"/>
<Operation Date="2018-11-06" Client="UL"/>
<Operation Date="2018-11-06"/>
</Operations>
</Document>
Thanks!

Answer 1

Try to read the attribute node, if it does not exist create it:
For Each node In oAttributes
If (node.getAttributeNode("Client") Is Nothing) Then
'// add missing attrib
node.setAttribute "Client", "UL"
End If
Your current code seems to want all elements to have Client=UL, to accomplish that simply:
For Each node In oAttributes
node.setAttribute "Client", "UL"
Next node
Which will overwrite or create the attribute as needed.