I would like to be able to allow a user to enter a custom formula in a cell in Excel which will subscribe to data provided by an external .NET application. For example, the user might enter…
There is an external .NET (C#) application that is determining the value of “ABC” every minute.
The cell should display the initial value of “ABC” from the external application and update when the external application sends a new value.
In the past I think the external application would be a DDE server and the formula would be a DDE client formula but DDE is apparently dead. What is the “correct” technology to use to do this?
Note that the spreadsheet needs to pull the data via a formula. The information is not going into a fixed template excel file but into any spreadsheet into which the user enters a formula.
Excel RTD (Real Time Data) is the replacement for DDE. It allows you to push values to a cell whenever updates are available. If the process providing the updates is an external application, setting up a WCF channel between the RTD server and the external app should allow you to feed real-time updates into Excel.
Here are some links:
You can communicate with Excel sheets through the Excel Api: