Fixing #69

Author: aaronpowell

CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog for `FSharp.CosmosDb`
 
+## [1.2.1] - Unreleased
+
+### Fixes
+
+- Fixing #69 by finding a property using conventions first, before raising an error
+
 ## [1.2.0] - 2022-08-22
 
 ### Added

src/FSharp.CosmosDb/OperationHandling.fs

@@ -11,7 +11,11 @@ let getIdFieldName<'T> (item: 'T) =
 
     match idAttr with
     | Some attr -> attr.GetValue(item).ToString()
-    | None -> "id"
+    | None ->
+        let property = item.GetType().GetProperties() |> Array.tryFind(fun p -> p.Name.Equals("id", StringComparison.InvariantCultureIgnoreCase))
+        match property with
+        | Some property -> property.GetValue(item).ToString()
+        | None -> failwith "Unable to determine the id field of the type. Either use the IdAttribute or have a field named Id"
 
 let getPartitionKeyValue<'T> (single: 'T) =
     let partitionKey = PartitionKeyAttributeTools.findPartitionKey<'T> ()