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This section contains information about user-defined functions (UDFs) and how to use UDF attributes in your code.
Understanding Excel Services UDFs
Learn about managed-code UDFs, including required attributes, deployment, and security.
Walkthrough: Developing a Managed-Code UDF
Get step-by-step instructions about developing Excel Services UDFs by using Microsoft Visual C#.
Frequently Asked Questions About Excel Services UDFs
Find answers to the most common questions about Excel Services UDFs.
Learn how to enable UDFs and allow them to be called from an Excel workbook.
How to: Create a UDF That Calls a Web Service
Learn how to call an external Web service from a UDF.
How to: Access an External Data Source from a UDF
Get an example showing how to access an external database from a UDF.
How to: Deploy UDFs Using SharePoint Foundation Solutions
Learn how to deploy a UDF by using the s solution framework.
How to: Restrict UDF Code Access Security Permissions
Learn how to create a custom code group and restrict permission for a UDF assembly by using the .NET Framework Configuration tool.
[Microsoft.Office.Excel.Server.Udf]
Excel Services UDF attributes.
Events
Microsoft 365 Community Conference
May 6, 2 PM - May 9, 12 AM
Skill up for the era of AI at the ultimate community-led Microsoft 365 event, May 6-8 in Las Vegas.
Learn moreTraining
Module
Expand query and transaction functionality in Azure Cosmos DB for NoSQL - Training
Author user-defined functions and triggers using JavaScript in Azure Cosmos DB for NoSQL.
Certification
Microsoft Office Specialist: Excel (Office 2016) - Certifications
Demonstrate that you have the skills needed to get the most out of Excel 2016 by earning a Microsoft Office Specialist (MOS) certification.