In my on-going attempts at providing a more useful lookup column using BDC, I hit a wall with the BDC picker. If you haven’t see it, the BDC picker is similar to a people picker except that it works with columns of type "business data".

You access the picker by clicking on the open book icon of a business data column as shown:

The above image shows a business data column called "Master Document Id". That column is connected, via BDC, to a web service. The web service returns two columns of information: Document ID and Title. The business purpose here is to provide a "this document is based on" funzjoni. Users select a "master" document and when they save, an event receiver copies meta data fields from the referenced master.

By default, the BDC picker looks like this when I search for a document whose ID = "38":

That’s helpful, but not good enough. People don’t think in terms of IDs, they think in terms of titles and/or other meta data. The picker allows you to search on other columns (e.g. Titolu) but won’t show the actual list of titles it found, just their DocId’s as shown here:

(The screen shot isn’t so great because I didn’t pick a search that returns any valid results, but you can see that if it had found some results, it would only have shown DocId’s, not titles).

I searched high and low for the answer to this and failed. Kollega tiegħi, the venerable Jonathan Bradshaw, had faced and solved this issue. When I reached out to him for help, he pointed me in the right direction.

Configure the picker to show multiple columns via the "ShowInPicker" property in the ADF:

<Proprjetà Isem="ShowInPicker" Tip="System.Boolean">vera</Proprjetà>

In more detail:

  <!-- Titolu -->
  <TypeDescriptor TypeName="System.String" Isem="Titolu" >
    <LocalizedDisplayNames>
      <LocalizedDisplayName LCID="1033">Titolu</LocalizedDisplayName>
    </LocalizedDisplayNames>
    <Properties>
      <Proprjetà Isem="DisplayByDefault" Tip="System.Boolean">vera</Proprjetà>
      <Proprjetà Isem="ShowInPicker" Tip="System.Boolean">vera</Proprjetà>
    </Properties>
  </TypeDescriptor>

Setting this property does introduce a minor problem. As soon as you set it once, you need to set it for every column you want to show. Fil-każ tiegħi, BDC picker showed DocId by default. Madankollu, once I added "ShowInPicker" to Title, DocId no longer displayed. I solved that by explicitly setting the ShowInPicker property for Doc ID.

Here is the result:

(I’ll explain the odd-looking "168 – CamlSchema.xsd" construction in a future blog post. In short, it’s a concatenated string that allows for a slightly better user experience).

Of course, having written this blog entry, I just did a search for "ShowInPicker" and found numerous hits, including this one: http://msdn2.microsoft.com/en-us/library/ms583986.aspx. It explains the meaning of that property along with some other good BDC stuff.

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Abbona għall-blog tiegħi!