Lookup in Excel - creating a custom lookup

To facilitate data entry, the Excel App provides lookups and data assistance. Date fields provide a date picker, enumeration (enum) fields provide an enum list, and relationships provide a relationship lookup. When relationships exist between entities, a relationship lookup is shown. We can create custom lookups to show data options when an enum or relationship isn't sufficient. The main use case is when data must be retrieved from an external service and presented in real time.

In this recipe, we will show how to add a custom lookup on currency code on a vendor's entity.

How to do it...

Carry out the following steps in order to complete this recipe:

1. Open the previously created project in Visual Studio.
2. Open the Designer View for VendVendorEntity. Right-click on Methods and then click on New Method.
3. Add the lookup_CurrencyCode method from the following code sample:

    [SysODataActionAttribute("VendVendorEntityCustomLookup", false),
    //Name in $metadata...