Setting null for single-valued navigation property using Xrm.WebApi

Question

We are in the process of remediation, re-engineering old JS web resources for latest D365 v9 sdk changes w.r.t Client scripting API improvements & deprecation.

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Answer 1

Great news! You can set lookup field to null in PATCH request by adding this header to your request.

autodisassociate: true

And then you can use something like this to alter your lookup field in any way:

SetLookupField(requestBody, "systemusers", "msdfm_MyUser", null)
// Or
SetLookupField(requestBody, "systemusers", "msdfm_MyUser", "f5b0b514-aea8-ea11-a812-000d3a569fe1")

// ...

private static void SetLookupField(JObject requestBody, string typePlural, string name, string value)
{
    if (!string.IsNullOrEmpty(value))
    {
        requestBody.Add($"{name}@odata.bind", $"/{typePlural}({value})");
    }
    else
    {
        requestBody.Add($"_{name.ToLower()}_value", null);
    }
}

OP uses XMLHttpRequest anyway, so I thought, a way to do this using PATCH will be relevant here.

Answer 2

I just tried in v9.1.0.3832 var data = { _[LookupFieldName]_value : null } is working for me.

var data =
{
  "statecode": 1,
  "*_myprefix_mylookupfieldname_value*": null
}
Xrm.WebApi.updateRecord("*entityName*", *recordId*, data);

Answer 3

You have to use Delete method to remove the lookup value format is as follows: /api/data/v8.0/accounts(1DD18913-11CB-E511-80D2-C4346BDC11C1)/primarycontactid/$ref

Answer 4

To set null on the lookup use:

var data = { _[LookupFieldName]_value : null } 
Xrm.WebApi.updateRecord("abc_entity", abc_entityid, data).then(successCallback, errorCallback

For example to remove contact.parentcustomerid field value you need to use:

var data = {};
data._parentcustomerid_value = null
var t = await Xrm.WebApi.updateRecord("contact", "{0200E6F5-1D21-E811-A954-0022480042B3}", data)