I'm trying to use LiveBindings to format a number for display in a TEdit on a FireMonkey form.
I'm trying to use the Format method in the CustomFormat of the binding to format the number with two decimal places.
I can 'hard code' the output:
Format("Hello", %s)
which is working, but I can't work out what formatting string to use. If I try a standard formatting string such as,
Format("%.2f", %s)
I get a runtime error "Format invalid or incompatible with argument".
Indeed I get an error whenever I include a % symbol in the format string, so I'm guessing Format takes a different type of argument, but I can't find any documentation to say what the correct format string is.
The parameter is passed into CustomFormat as %s. The bindings system preparses out this parameter before the data is passed onto the evaluator. Thus any other % symbols in the CustomFormat string will give an error.
As with a normal format string you can include a literal % sign by putting a double % (i.e. %%).
So, any %s in the format string need to be converted to %%, e.g.
Format('%%.2f', %s)
which gets parsed out to
Format('%.2f', 67.66666)
and then parsed down to
67.67
for display.
If you want to include a literal % in the final output you need to put a quadrupal %, e.g.
Format('%%.2f%%%%', %s)
becomes
Format('%.2f%%', 67.6666)
and displays as
67.67%
Note: The normal format function takes a final parameter which is an array of values. The Format method in the bindings system takes a variable length list of parameters.
Also, the method names are case sensitive. 'Format' is correct, 'format' will fail.