Creating XML structures

XML is a special protocol for describing structured data in a string. XML data is also used to power other applications, such as a CRM system or ERP system, with data.

TCE uses the Microsoft XML type library, which is available in different versions, provided in Windows systems.

The XML structure should be created on the server, so it is only necessary to enable the Typelib switch for this type library. You can reach the Typelib by clicking on the New Type Library button.

In this example, we want to create an XML for all materials.

A well-formed XML looks like this:

</Root>

'It consists of exactly one root node, here with the name Root. The root node starts with the tag <Root> and ends with the tag </Root>.

A node can have one or more attributes, such as xmlns:dt and Product. Attributes get a value over an equal sign and the actual value in commas.

There can be one or more nodes between the root node tags that follow the same syntax:

<Material>…</Material>'

A shortened spelling is possible if the node does not have any more child nodes.

We now want to generate this XML in TCE.

In the Start class, we create a function called Interface:

Public Function Interface() As MSXML2.DOMDocument

Dim DOM As New MSXML2.DOMDocument, oEle As MSXML2.IXMLDOMElement, XMLRoot As MSXML2.IXMLDOMNode

XMLRoot := DOM.appendChild(DOM.createElement("Root"))

oEle := XMLRoot

oEle.setAttribute("xmlns:dt", "urn:schemas-microsoft-com:datatypes")

XMLRoot.attributes.setNamedItem(DOM.createAttribute("Product")).nodeTypedValue := Product.ObjectClass.Name

Dim Mat As ::Material

For Each Mat In Me.ObjectList(::Material,, True)

Mat.Interface(DOM, XMLRoot)

End For

End Function DOM

In the Microsoft XML library, the object used to describe an XML is called DOMDocument, an object that describes data type conventions is Called IXMLDOMElement, and an object to describe a node in the XML is called XMLDOMNode.

The function first generates an object of type DOMDocument in the variable DOM. This is already done with the help of the New keyword, which is creating an object on first access.

Dim DOM As New MSXML2.DOMDocument, oEle As MSXML2.IXMLDOMElement, XMLRoot As MSXML2.IXMLDOMNode

Then the root node root is generated via the DOMDocument object and the reference to this object is stored in the XMLRoot variable.

XMLRoot := DOM.appendChild(DOM.createElement("Root"))

Now the (optional) element for data type description is created in the root node:

oEle := XMLRoot

oEle.setAttribute("xmlns:dt", "urn:schemas-microsoft-com:datatypes")

Now an attribute product is created in the root node and its value is set:

XMLRoot.attributes.setNamedItem(DOM.createAttribute("Product")).nodeTypedValue := Product.ObjectClass.Name

Now all material objects are looped through. For each material object, the function Interface with the transfer of the DOM and the root node is called.

Dim Mat As ::Material

For Each Mat In Me.ObjectList(::Material,, True)

Mat.Interface(DOM, XMLRoot)

End For

The DOM object is finally returned as the return parameter of the function.

What does the function Interface of the Material class look like, which is called in the loop?

Function Interface(ByRef DOM As MSXML2.DOMDocument, ByRef ParentNode As MSXML2.IXMLDOMNode) As Void

Dim Node As MSXML2.IXMLDOMNode

Node := ParentNode.appendChild(DOM.createElement("Material"))

Node.attributes.setNamedItem(DOM.createAttribute("NumberOf")).nodeTypedValue := NumberOf

Node.attributes.setNamedItem(DOM.createAttribute("ID")).nodeTypedValue := Me.ObjectClass.Name

Node.attributes.setNamedItem(DOM.createAttribute("PositionPrice")).nodeTypedValue := [Position Price]

Node.attributes.setNamedItem(DOM.createAttribute("Description")).nodeTypedValue := Me.ObjectDescription

End Function

First, a new node is created as a child node of the ParentNode node. The reference to the new node is stored in the variable Node.

Node := ParentNode.appendChild(DOM.createElement("Material"))

After that, four attributes are bound to this node:

NumberOf, ID, PositionPrice and Description

Now let's try out XML generation:

We create a menu item with the name XML in the main menu to call the interface and in the click event we implement the following code:

Private Function Click() As Void

If Product.ValidChildElements = False Then

MsgBox(Messages.[Configuration invalid], TCEServer.MsgBoxStyle.Critical,, MainForm.hwnd)

Return

End If

Dim DOM As MSXML2.DOMDocument

DOM := Interface

MsgBox(DOM.xml) If DOM <> NoValue

End Function

Here we check in the beginning, if there are any invalid elements in our object tree of the product. In that case we stop the output of the XML.

You should get the following result: