I’m implementing a report with cells where a user can enter values. Those values I need to handle. I do the following: check ContainsValue check box, set ValueType to Number, set Contol to Text box. How can I get a value from this cell now?

Use SpreadsheetDocument.Area() to get cell and then Value to get value inside this cell.

Example:
Cell = Spreadsheet.Area("R2C5");
MyValue = Cell.Value;