How to change the LineWidth of a cell border using PyUNO in LibreOffice Calc?

Question

I am writing a Python script to automatically adjust cell borders in LibreOffice Calc. I think I know what property I need to change, however when I assign a new value to this property, the value does not change.

For instance, I wrote this code to change the TopLine.LineWidth of a single Cell from 0 to 10.

# Access the current calc document
model = desktop.getCurrentComponent()
# Access the active sheet
active_sheet = model.CurrentController.ActiveSheet
# Get the cell and change the value of LineWidth
cell = active_sheet.getCellByPosition(2, 2)
cell.TableBorder2.TopLine.LineWidth = 10

I don't get any errors after running this code. And I have also made sure that I am accessing the cell I wish to modify. However, this code does not change the cell's border width.

I tried doing some debugging by printing the value before and after the assignment:

# This first print statement returns 0 because the cell has no borders
print(cell.TableBorder2.TopLine.LineWidth)
cell.TableBorder2.TopLine.LineWidth = 10
# This second print statement still returns 0, but I was expecting it to return 10
print(cell.TableBorder2.TopLine.LineWidth)

Does anyone know what I am doing wrong?

Answer 1

You need to set the cell property to a changed border object. From https://ask.libreoffice.org/en/question/145885/border-macro-no-longer-works/:

aThinBorder = oRange.TopBorder2
aThinBorder.LineWidth = 1
oRange.TopBorder2 = aThinBorder

Answer 2

So, after doing a lot of research, I found at least three methods to change border settings. Because it took me so much effort, I figured I should leave them here so in the future other people may find the answer more easily.

In all examples I'll set the LineWidth of the TopBorder of a single cell to 10.

Method 1: Using getPropertyValue() and setPropertyValue()

cell = active_sheet.getCellByPosition(1, 1)
border_prop = cell.getPropertyValue("TopBorder")
border_prop.LineWidth = 10
cell.setPropertyValue("TopBorder", border_prop)

Method 2 (derived from Jim K's answer)

cell = active_sheet.getCellByPosition(1, 1)
border_prop = cell.TopBorder2
border_prop.LineWidth = 10
cell.TopBorder2 = border_prop

Method 3: Using a BorderLine2 struct

border_prop = uno.createUnoStruct("com.sun.star.table.BorderLine2")
border_prop.LineWidth = 10
cell = active_sheet.getCellByPosition(1, 1)
cell.setPropertyValue("TopBorder", border_prop)