Hi Piotr,
Based on shared information we have checked the issue in “Input string was not in a correct format” while change the editor type as NumericUpDown for the properties (PercentDisplayMode, ParsingMode, CultureInfo, FormatString) and we are unable to reproduce the issue.
We have prepared the simple sample for the same and please find the sample from below link.
Note:
We have ensured this scenario in cross platforms (Xamarin.Forms.iOS, Xamarin.Forms.Android and Xamarin.Forms.UWP) with Syncfusion product version 16.1.0.24.
If the above provided solution doesn’t meet your scenario, could you please share the simple issue reproducing sample or code snippet to reproduce the issue? So that we can analyze on your requirement further and provide you a possible solution.
Regards,
Srinivasan