This option is directly available.
In combo chart you have three choices for displaying metric - bars, line and marker.
Select Marker for the one which you wan to show as dotted line and choose appropriate symbol.
Capture.PNG 17.1 K
I can't provide the whole app, but let me try to clarify with the expressions I'm trying to put into this combo chart.
Percentage1: Count(If([Attempts] < 5 AND ([Type] = 'Type1' OR 'Type2'), [AttemptCode]))/Count(IF([Type] = 'Type1' OR 'Type2', [AttemptCode])) -- this formula exists to give me a percent of attempts that are fewer than 5.
I want the percentages to be represented by dotted or dashed lines.
I think the only way is to use marker (line) instead of line in qlik sense to simulate a dashed/dotted line, like Saravana already described. The option '<S1>' ~ '<S3>' can't be used to modify your line in qlik sense.
Please see attached pic
But it's not really a dashed/dotted line, especially if your values differs a lot.
I think the only possibility to use a real dashed/dotted line would be to use an extension or create it by yourself where you can modify the line style but until now you can't change it like in qlikview.