Update multi choice field using SharePoint Designer Workflow

Question

I have a requirement where, on item creation on list A (Announcement List), a workflow is triggered in which list items in List B are created. The semicolon separated values are entered in list A Body field. eg.

Training Topic:Admin Tools;

The workflow reads these values and loops through them by indexing semicolons and stores each values in variables. Finally item in list B is created for all fields filling with values of appropriate variables.

Everything is working fine if I remove multi-choice column from this (Training Topic in this case). The items in list B are created and mail is sent.

But when I add the multi-choice column, the internal status of workflow gets suspended and it throws the following error:

System.ApplicationException: HTTP 400 {"error":{"code":"-1, Microsoft.SharePoint.Client.InvalidClientQueryException","message":{"lang":"en-US","value":"An unexpected 'PrimitiveValue' node was found when reading from the JSON reader. A 'StartObject' node was expected.}}}

Note: Since I'm logging at every step, I can see the correct string value is stored in the variable which is to be the value of the multi-choice field during creation. So the problem is probably not with the variable, it has something to do with the creation of multi-choice field.

Answer 1

Basically we're trying to update a MultiChoice column with comma seperated value. Below hack works for me. I don't think this would be the recommended way.

I create a template variable:
{"__metadata":{"type":"Collection(Edm.String)"},"results":[ITEMS]}

A data variable:
"Apple","Mango"

Now, we replace ITEMS with our data in template. So that the final variable, say json, becomes {"__metadata":{"type":"Collection(Edm.String)"},"results":["Apple","Mango"]}

Update list item multichoice column with Json variable. We're done!