Filtering Entities with type Entity Reference?

Question

How do I query using the string value for an entity reference object?

QueryExpression query = new QueryExpression(\"entityName\");
query.Criteria = new FilterExp         


        

Answer 1

While it appears that we're out of luck on getting the "like" operator to compare a string to a GUID on the fly, there are at least a couple potential workarounds:

1. Retrieve all the GUID's, convert them to a list of strings, and find your subset by querying that list (i.e. with LINQ).
2. Write a very simple onCreate plugin or workflow that sets a new text field on the entity to the GUID. Then you have the GUID as a string, to work with as you please.

Here's code I use in a workflow that does exactly what I'm describing (i.e. populates the GUID into a text field). It sets an output parameter to the GUID, then the next step of the workflow populates that value into the field.

public partial class GetGuid : BaseWorkflow
{
    [Output("Entity Id")]
    public OutArgument EntityId { get; set; }

    protected override void ExecuteInternal(LocalWorkflowContext context)
    {
        EntityId.Set(context.CodeActivityContext, context.WorkflowContext.PrimaryEntityId.ToString());
    }
}

Please also note that while the "like" operator doesn't work for GUID's, "greater than" and "less than" do, so something like this works: