Python and .NET Version Differences

Aspose.Words for Python via .NET is a wrapper of Aspose.Words for .NET, that is why the two products have almost the same set of features. Nevertheless, there are some nuances of work and differences in features and API, which are described on this page.

Feature Differences

Due to the wrapping process there are some features that are not available in the Python version. Here is a list of the most notable features that are currently are not available in the Python version.

  • Implementation of interfaces is not supported yet, that is why it is not possible to use callbacks such as IWarningCallback, IReplacingCallback, IFieldUpdatingCallback, IFieldMergingCallback etc.
  • Printing feature is not available because .NET Standard 2.0 version of Aspose.Words is used as back-end of the python version, which also does not provide this functionality.
  • Only simple Mail Merge functionality is provided with arrays of field names and field values as a data source.
  • DocumentVisitor implementation is currently not possible from the Python code.

Casting Aspose.Words Objects in Python

Though type casting is not natural for Python developers some tasks cannot be accomplished without casting documents nodes or fields to concrete type. Aspose.Words for Python via .NET provides special methods that allow casting objects where this is necessary.

Casting Nodes

Base class for all document nodes in Aspose.Words DOM is Node class. For example get_child method returns and instance of Node class, but if you need to modify the returned node, in most cases you should to cast it to concrete type. The following code demonstrates how to change font color of the first Run in the document:

doc = aw.Document(docs_base.my_dir + "Document.docx")

# Get the first Run node and cast it to Run object.
run = doc.get_child(aw.NodeType.RUN, 0, True).as_run()

# Make changes to the run 
run.font.color =

# Save the result + "WorkingWithNode.change_run_color.docx")

Casting might be also required when clone method is used:

doc = aw.Document(docs_base.my_dir + "Document.docx")

clone = doc.clone().as_document() + "CloneAndCombineDocuments.cloning_document.docx")

As you might noticed where in C# code you would use (Paragraph)node for casting, in Python you have to use node.as_paragraph() method. In the Python version of Aspose.Words Node class introduces the following link of as_xxx methods:

The as_xxx method raise a RuntimeError with the message like the following if the node cannot be cased to the specified type:

RuntimeError: Proxy error(InvalidCastException): Unable to cast object of type ‘Aspose.Words.XXX’ to type ‘Aspose.Words.Drawing.YYY’.

Casting Fields

The same situation applied to fields. The following code example demonstrates how to replace hyper link links:

doc = aw.Document(docs_base.my_dir + "Hyperlinks.docx")

for field in doc.range.fields :
    if field.type == aw.fields.FieldType.FIELD_HYPERLINK:
        hyperlink = field.as_field_hyperlink()
        # Some hyperlinks can be local (links to bookmarks inside the document), ignore these.
        if hyperlink.sub_address != None :
        hyperlink.address = ""
        hyperlink.result = "Aspose - The .net & Java Component Publisher" + "WorkingWithFields.replace_hyperlinks.docx")

As you might noticed Field object also provides set of as_xxx methods, which are listed below:

Casting Styles

Casting is also required to work with table styles:

doc = aw.Document()
builder = aw.DocumentBuilder(doc)

table = builder.start_table()

# Add a table style and modify it's properties.
tableStyle = doc.styles.add(aw.StyleType.TABLE, "MyTableStyle1").as_table_style()
tableStyle.borders.line_style = aw.LineStyle.DOUBLE
tableStyle.borders.line_width = 1
tableStyle.left_padding = 18
tableStyle.right_padding = 18
tableStyle.top_padding = 12
tableStyle.bottom_padding = 12 = tableStyle + "WorkingWithTableStylesAndFormatting.create_table_style.docx")

Casting Ole Controls

The following code example demonstrates how to read ActiveX control properties:

doc = aw.Document(docs_base.my_dir + "ActiveX controls.docx")

properties = ""
for shape in doc.get_child_nodes(aw.NodeType.SHAPE, True) :
    shape = shape.as_shape()
    if shape.ole_format == None :
    oleControl = shape.ole_format.ole_control
    if oleControl.is_forms2_ole_control :
        checkBox =  oleControl.as_forms2_ole_control()
        properties = properties + "\nCaption: " + checkBox.caption
        properties = properties + "\nValue: " + checkBox.value
        properties = properties + "\nEnabled: " + str(checkBox.enabled)
        properties = properties + "\nType: " + str(checkBox.type)
        if checkBox.child_nodes != None :
            properties = properties + "\nChildNodes: " + checkBox.child_nodes
        properties += "\n"

properties = properties + "\nTotal ActiveX Controls found: " + str(doc.get_child_nodes(aw.NodeType.SHAPE, True).count)
print("\n" + properties)

Casting Font Sources

FontSourceBase class provides set of as_xxx methods, which are listed below:

Accessing Indexer Properties

Aspose.Words for Python does allow indexer properties only by int type, in .NET however it is possible to use other types, for example strings. To fill this gap the following classes has an additional methods:

API Members Naming

To be closer to Python world, API members of Aspose.Words for Python via .NET uses pythonic snake style, however in most cases they have one to one analog in Aspose.Words for .NET API. You can find these analog in the xml file.