Customize Field Properties

Aspose.Words provides the ability to programmatically interact with various field properties. In this article, we will look at a couple of examples so that you understand the basic principle of working with field properties. You can see the full list of properties for each field type in the corresponding class in the Fields module.

Field Property Update

Sometimes users need to change the value of a field property. For example, update the author_name property of the AUTHOR field or change the field_name property of the MERGEFIELD field.

The following code example shows how to rename merge fields in a Word document:

Field Display Result

Aspose.Words provides a property to obtain the field’s result for fields that do not have a field separator node. We call this “fake result” or display result; MS Word displays it in the document by calculating the field’s value on the fly, but there is no such value in the document model.

The following code example shows the usage of display_result property:

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FAQ

1. Q: How can I rename a MERGEFIELD in a Word document using Python?
   A: Load the document, iterate through its fields, cast each FieldMergeField and set the field_name property to the new name. After updating, save the document. Example:

   import aspose.words as aw
   
   doc = aw.Document("input.docx")
   for field in doc.range.fields:
       if isinstance(field, aw.fields.FieldMergeField):
           merge_field = aw.fields.FieldMergeField(field)
           merge_field.field_name = "NewFieldName"
   doc.save("output.docx")
   

2. Q: How do I retrieve the display result of a field that has no separator node?
   A: Use the display_result property of the Field object. It returns the value that Word would show for the field even when the field result is not stored in the document.

   import aspose.words as aw
   
   doc = aw.Document("input.docx")
   for field in doc.range.fields:
       print(f"Field type: {field.type}, Display result: {field.display_result}")
   

3. Q: Can I change the author name of an AUTHOR field programmatically?
   A: Yes. Cast the field to FieldAuthor and set its author_name property, then save the document.

   import aspose.words as aw
   
   doc = aw.Document("input.docx")
   for field in doc.range.fields:
       if isinstance(field, aw.fields.FieldAuthor):
           author_field = aw.fields.FieldAuthor(field)
           author_field.author_name = "John Doe"
   doc.save("output.docx")
   

4. Q: How can I determine whether a field contains a separator node?
   A: The has_separator property of a Field indicates the presence of a separator. It returns True if the field has a separator node, otherwise False.

   import aspose.words as aw
   
   doc = aw.Document("input.docx")
   for field in doc.range.fields:
       print(f"Field type: {field.type}, Has separator: {field.has_separator}")
   

5. Q: Is it possible to list all available properties for a specific field type?
   A: Yes. Each field type has a dedicated class in the aspose.words.fields namespace. You can refer to the documentation for that class (e.g., FieldMergeField, FieldAuthor) to see all its properties and methods. In code, you can use dir() on an instance to inspect available members.

   import aspose.words as aw
   
   merge_field = aw.fields.FieldMergeField()
   print(dir(merge_field))   # Shows all properties and methods of FieldMergeField