Exemplos de QgsExpressionContext::fields em C++ (Cpp)

Exemplo n.º 1

Arquivo: qgsproperty.cpp Projeto: enzogis/QGIS

bool QgsProperty::prepare( const QgsExpressionContext &context ) const
{
  if ( !d->active )
    return true;

  switch ( d->type )
  {
    case StaticProperty:
      return true;

    case FieldBasedProperty:
    {
      d.detach();
      // cache field index to avoid subsequent lookups
      QgsFields f = context.fields();
      d->cachedFieldIdx = f.lookupField( d->fieldName );
      return true;
    }

    case ExpressionBasedProperty:
    {
      d.detach();
      if ( !d->expression.prepare( &context ) )
      {
        d->expressionReferencedCols.clear();
        d->expressionPrepared = false;
        return false;
      }

      d->expressionPrepared = true;
      d->expressionReferencedCols = d->expression.referencedColumns();
      return true;
    }

    case InvalidProperty:
      return true;

  }

  return false;
}