Knowledge Base

KB10259 - Programmatically render layer using field values in a joined external database. (code example)

For example:

  sqlDC := CreateOleObject('ADODB.Connection');

  sqlRS := CreateOleObject('ADODB.Recordset');

  sqlDC.Open('FILEDSN=GMINY.DSN');

  sqlRS.Open('select id, agri FROM QTocounty ORDER BY id', sqlDC);

  // order by ID is important!!!!



  // ll is your layer with a unique 'zone' field

  ll.ADOJoin := sqlRS;

  ll.ADOJoinPrimary := 'zone';

  ll.ADOJoinForeign := 'id';



  ll.RenderExpression := 'age'; // if our external database has such field.

  ll.RenderMinVal := 0;

  ll.RenderMaxVal := 100;

  ll.RenderZones := -5; // crucial - must be something.



  ll.RenderColorDefault := clBlue; // is nothing match

  ll.UseConfig := False; // turn off config file suggestion

  ll.RenderStartColor := clwhite;

  ll.RenderEndColor := clGreen;

  ll.AreaColor := GIS_RENDER_COLOR;

  ll.AreaOutlineWidth:=0;

Created: November 21, 2003, Modified: December 22, 2015