Background format

Background colors and patterns are set using the cell's interior object property:

With ActiveSheet.Range("A1").Interior
	.ColorIndex = 3
	.Pattern = xlGray50
	.PatternColorIndex = 13
End With

In AppleScript:

tell application "Microsoft Excel"
	tell interior object of range "A1" of active sheet
		set color index to 3
		set pattern to pattern gray 50
		set pattern color index to 13
	end tell
end tell

This allows you to superimpose a fine-grained pattern (if you want) with its own color over the basic interior color to get a very wide variety of blended colors.

Borders

You can get every border in AppleScript, but it requires more code than in VBA if you need to get all of them at once.

In VBA, borders are an integral part of the object model and are set using the cell's Borders Collection and Border objects. You can set all of the (outside) borders at once using the collection properties:

With ActiveSheet.Range("D10").Borders
	.LineStyle = xlDouble
	.ColorIndex = 3
End With

Or, you can set borders individually, which is much more analogous in AppleScript.

Borders could not be implemented as elements of range or other objects, though it seems they could be in the sense that they have a many-to-one relationship with the object they're bordering. But they cannot be elements because they are somewhat read-only in that you cannot make new borders or delete existing ones.

You can change their properties, so they are "writable" in that sense. For anything defined as an element, you may want to make new border at range, but you can't do that, or delete any. Borders are just there.

You also can't use a single border property with enumerated constants for the different types. Borders need to be fully-fledged objects whose properties you can modify: collection object types. AppleScript does not have those. AppleScript doesn't fit built-in, read-only elements into its model. These are dealt with in VBA as collection objects, but become orphans in AppleScript, with no parent aside from base object in AppleScript. The same issue exists with headers and footers in Microsoft Word.

In both cases, you have to do the same thing — only, unlike headers and footers, there are more than six borders. There are 12. You have to use the command get border and specify which border, 12 times, to retrieve each of the 12 borders separately. Word manages borders the same way.

Here is how you have to do it if you want to set the line style and color index of all borders of a cell or range, as in the VBA snippet above:

tell application "Microsoft Excel"
	tell range "D10" of active sheet
		set allBorders to {} -- initialize a list
		set end of allBorders to get border ¬
			which border border bottom
		set end of allBorders to get border ¬
			which border border left
		set end of allBorders to get border ¬
			which border border right
		set end of allBorders to get border ¬
			which border border top
		set end of allBorders to get border ¬
			which border diagonal down
		set end of allBorders to get border ¬
			which border diagonal up
		set end of allBorders to get border ¬
			which border edgebottom
		set end of allBorders to get border ¬
			which border edge left
		set end of allBorders to get border ¬
			which border edge right
		set end of allBorders to get border ¬
			which border edge top
		set end of allBorders to get border ¬
			which border inside horizontal
		set end of allBorders to get border ¬
			which border inside vertical
	end tell
	repeat with thisBorder in allBorders
		try
			set line style of thisBorder to double
		end try
		try
			set color index of thisBorder to 3
		end try
	end repeat
end tell

In this case, you set the end of a list to each new border, which is a more efficient way of building a list than concatenating lists. It makes no discernible difference when you've just got just one or a few items to process, but if you have to repeat this whole procedure hundreds of times over, it could make a significant difference to the speed of the script.

You can't set the line style (nor any other property) of the whole list at once. The script errors, even if you can exclude any nonexistent borders. So you have to run a repeat loop on each member of the list, using try/end try for each border. In the case of a standard default worksheet cell, both commands error on the last two borders (inside horizontal and inside vertical), which may mean that they don't really exist, although some object is returned from the get border command each time.

Since you can't run a command (set line style, etc.) on the whole list at once, there isn't much advantage in having the list. You could instead set the line style and color index for each border as you make it, sending each border out to a handler to be processed, like this:

tell application "Microsoft Excel"
	tell range "D10" of active sheet
		set thisBorder to get border ¬
			which border border bottom 
		my ModifyBorder(thisBorder)
		set thisBorder to get border ¬
			which border border left
		my ModifyBorder(thisBorder)
		set thisBorder to get border ¬
			which border border right
		my ModifyBorder(thisBorder)
		set thisBorder to get border ¬
			which border border top
		my ModifyBorder(thisBorder)
		set thisBorder to get border ¬
			which border diagonaldown
		my ModifyBorder(thisBorder)
		set thisBorder to get border ¬
			which border diagonal up
		my ModifyBorder(thisBorder)
		set thisBorder to get border ¬
			which border edge bottom
		my ModifyBorder(thisBorder)
		set thisBorder to get border ¬
			which border edge left
		my ModifyBorder(thisBorder)
		set thisBorder to get border ¬
			which border edge right
		my ModifyBorder(thisBorder)
		set thisBorder to get border ¬
			which border edge top
		my ModifyBorder(thisBorder)
		set thisBorder to get border ¬
			which border inside horizontal
		my ModifyBorder(thisBorder)
		set thisBorder to get border ¬
			which border inside vertical
		my ModifyBorder(thisBorder)
	end tell
end tell
 
on ModifyBorder(thisBorder)
	tell application "Microsoft Excel"
		try
			set line style of thisBorder to double
		end try
		try
			set color index of thisBorder to 3
		end try
	end tell
	return
end ModifyBorder

This is actually more efficient. Either method works well. You need change only the commands, in the ModifyBorder handler or in the repeat loop of the first method, to apply different effects to all of your borders.

Most of the time you will be setting properties of just one, or a few, borders. Here is what the VBA version might look like:

With ActiveSheet.Range("D10")
	.Borders.LineStyle = xlNone ' Remove existing borders
	With .Borders(xlEdgeLeft)
		.LineStyle = xlContinuous
		.Weight = xlThin
		.ColorIndex = 3
	End With
	With .Borders(xlEdgeRight)
		.LineStyle = xlContinuous
		.Weight = xlThick
		.ColorIndex = 3
	End With
End With

To remove all existing borders, run either sequence above, but change the commands in the repeat loop or ModifyBorder handler to:

set line style of thisBorder to line style none

Then follow with:

tell application "Microsoft Excel"
	tell range "D10" of active sheet
	set thisBorder to get border ¬
		which border edge left
		tell thisBorder
			set line style to continuous
			set weight to border weight thick
			set color index to 3
		end tell
		set thisBorder to get border ¬
			which border edge right
		tell thisBorder
			set line style to continuous
			set weight to border weight thick
			set color index to 3
		end tell
	end tell
end tell

Since you are making the same three settings to each of the two edge borders, again it would be better practice to use a handler to customize the operation:

tell application "Microsoft Excel"
	tell range "D10" of active sheet
		set thisBorder to get border ¬
			which border edge left
		my Customize(thisBorder)
		set thisBorder to get border ¬
			which border edge right
		my Customize(thisBorder)
	end tell
end tell
 
on Customize(thisBorder)
	tell application "Microsoft Excel"
		tell thisBorder
			set line style to continuous
			set weight to border weight thick
			set color index to 3
		end tell
	end tell
end Customize

You will notice that it is possible to send an application object out to an external handler as a parameter even though that takes it outside of the Microsoft Excel application block. The handler can still accept the item (which it will know as border id border edge left of cell "D10" of active sheet of application "Microsoft Excel") to pass back into the application tell block within the handler when called.