In the class we provided, the RTF property of the TextBox is directly assigned with no formating. Thus the format must already be valid, or else it will throw an exception. The content of the cell must be valid so it can be assigned to the RTF property.
You can simply test this by using the RichTextBox control outside the gird. Simply assigned a value to the RTF property that is the same as a cell value you are using, and see if it throws the exception. If it does, it means the format is not right.
Imported from legacy forums. Posted by André (had 2520 views)