This past week I was implementing an "evolving" solution for a client that uses BDC and SPQuery and ran into some difficulty using SPQuery against a document library containing folders. Bottom line: assign "recursive" leis an tréith bhfianaise an cheist.

Mo scéal:

• Ar Dé Luain, Mé a uaslódáil doiciméad agus roinnt sonraí meta sholáthar.
• An tseachtain seo a leanas, I upload a new document. Much of this new document’s meta data is based on the document I uploaded on Monday (which we call the "master document").
• Cruthaithe againn ar aghaidh seirbhís gréasáin a sholáthraíonn comhéadan BDC-chairdiúil leis an liosta ionas gur féidir le húsáideoirí a aimsiú go héasca an doiciméad Dé Luain trí chuardach teidil.
• A BDC data column provides a friendly user interface. (Tá sé seo mar chuid de mo iarracht ag baint úsáide as BDC ar feadh colún Lookup níos cairdiúla).

Úsáideann an aghaidh a BDC seirbhís deiridh ar cheist mar seo a dhéanamh ar an lookup:

 // Úsáidte uirlis U2U chun cabhrú ghiniúint an cheist CAML.
      oQuery.Query =
        "<I gcás>";

      más rud é (titleFilter.Length > 0)
        oQuery.Query   =
          "  <Agus>";

      oQuery.Query   =
        "    <Agus>" +
        "      <Geq>" +
        "        <FieldRef Name=\"DocumentId\" />" +
        "        <Value Type=\"Text\">" + MinID + "</Luach>" +
        "      </Geq>" +
        "      <Leq>" +
        "        <FieldRef Name=\"DocumentId\" />" +
        "        <Value Type=\"Text\">" + maxId + "</Luach>" +
        "      </Leq>" +
        "    </Agus>";

      más rud é (titleFilter.Length > 0)
        oQuery.Query   =
          "    <Tá>" +
          "      <FieldRef Name=\"Title\" />" +
          "      <Value Type=\"Text\">" + titleFilter + "</Luach>" +
          "    </Tá>" +
          "  </Agus>";
      oQuery.Query   =
        "</I gcás>";

Le linn an gcéad chéim na forbartha, this worked great. Mar sin féin, thugamar isteach fillteáin isteach an t-eolaire a réiteach roinnt fadhbanna agus go tobann, my BDC picker wouldn’t return any results. I tracked this down to the fact that the SPQuery would never return any results. We used folders primarily to allow multiple files with the same name to be uploaded but with different meta data. When the file is uploaded, a chruthú dúinn fillteán atá bunaithe ar an mír liosta ID agus ansin bogadh an comhad ann (Scríobh mé faoi sin anseo; tá muid go raibh torthaí measctha leis an gcur chuige seo, ach ar an iomlán, tá sé ag obair go maith). The user don’t care about folders and in fact, don’t really understand that there are any folders. We have configured all the views on the library to show items without regard to folders.

I hit this problem twice as the technical implementation evolved and solved it differently each time. The first time, I wasn’t using the CONTAINS operator in the query. Without a CONTAINS operator, I was able to solve the problem by specifying the view on the SPQuery’s contructor. Instead of using the default constructor:

SPList oList = web.Lists["Documents"];

SPQuery oQuery = nua SPQuery();

Úsáid mé ina ionad sin Cruthaitheoir atá sonraithe d'fhonn:

SPList oList = web.Lists["Documents"];

SPQuery oQuery = nua SPQuery(oList.Views["All Documents"]);

Sin réiteach ar an bhfadhb agus thosaigh mé a fháil ar mo torthaí.

I then added the CONTAINS operator into the mix and it broke again. It turns out that the CONTAINS operator, a mhéid is féidir liom a rá, nach bhfuil ag obair leis an dearcadh ar an mbealach céanna leis an a GEQ níos simplí / LEQ operators. I did some searching and learned that the query’s ViewAttributes should be set to "Recursive", mar atá i:

oQuery.ViewAttributes = "Scope=\"Recursive\"";

That solved the problem for CONTAINS. Go deimhin, seo a réiteach freisin mo fhadhb cuardaigh bunaidh agus dá mbeadh sonraithe mé an tréith recursive an chéad uair, Ní ba mhaith liom a bheith ar siúl ar an cheist arís.

Ar an bhfíric go n-oibríonn SPQuery dearcadh-bhunaithe le haghaidh roinnt oibreoirí (GEQ/LEQ) agus ní daoine eile (BhFUIL), chomh maith leis an bhfíric nach bhfuil KPI cosúil a bheith ag obair ar chor ar bith le leabharlanna doiciméad fillteán iontu mar thoradh ar dom chun a chreidiúint go bhfuil go SPQuery roinnt saincheisteanna orthogonality.

Go raibh maith agat Speisialta:

• Na folks maith ag U2U agus a n-uirlis fhiosraithe.
• Michael Hoffer ar mór "foghlama ag déanamh" blog post, tuairimí agus freagraí.

</deireadh>

Liostáil le mo bhlag!