Conditional formatting: cell value rules only accept numbers

[elsaminsut]

Description

In Excel, cell value rules (such as "cell value equals," "between," "greater than") accept numeric values, strings, and dates, enabling comparisons with different data types. For example, users can highlight dates before a specific date or text values alphabetically after "R".

IronCalc cell value rules only accept numbers, on the other hand. While IronCalc includes own rules like "date is between" for better user experience, this design choice sacrifices Excel compatibility. To maintain Excel compatibility, cell value rules should accept all value types (numbers, strings, dates) so users can create rules like "text is greater than R" or "date is after [specific date]".

Example

IronCalc - issue 1237

This example includes cell value rules containing:

• Dates: cell value greater than 45772 (a number, so it works), and cell value greater than 2025-4-25 (doesn't work)
• Strings: cell value greater than R, cell value equals "Berlin"
• Booleans: cell value equals 1, cell value equals TRUE
• Empty strings: cell value equals ""