[Delphi] How would you refactor this code?
- by Al C
This hypothetical example illustrates several problems I can't seem to get past, even though I keep trying!! ... Suppose the original code is a long event handler, coded in the UI, triggered when a user clicks a cell in a grid. Expressed as pseudocode it's:
if Condition1=true then
begin
//loop through every cell in row,
//if aCell/headerCellValue>1 then
//color aCell red
end
else if Condition2=true then
begin
//do some other calculation adding cell and headerCell values, and
//if some other product>2 then
//color the whole row green
end
else show an error message
I look at this and say "Ah, refactor to the strategy pattern! The code will be easier to understand, easier to debug, and easier to later extend!" I get that.
And I can easily break the code into multiple procedures.
The problem is ultimately scope related. Assume the pseudocode makes extensive use of grid properties, values displayed in cells, maybe even built-in grid methods. How do you move all that to another unit, without referencing the grid component in the UI--which would break all the "rules" about loose coupling that make OOP valuable? ...
I'm really looking forward to responses. Thanks, as always -- Al C.
