How to: Programmatically Store and Retrieve Date Values in Excel Ranges
You can store and retrieve values in a NamedRange control or a native Excel range object.
Applies to: The information in this topic applies to document-level projects and VSTO add-in projects for Excel. For more information, see Features Available by Office Application and Project Type.
If you store a date value that falls on or after 1/1/1900 in a range using Office development tools in Visual Studio, it is stored in OLE Automation (OA) format. You must use the FromOADate method to retrieve the value of OLE Automation (OA) dates. If the date is earlier than 1/1/1900, it is stored as a string.
Excel dates differ from OLE Automation dates for the first two months of 1900. There are also differences if the 1904 date system option is checked. The code examples below do not address these differences.
This example is for document-level customizations. The following code must be placed in a sheet class, not in the ThisWorkbook class.