columns - Columns

Columns are, usually, defined for collections in order to select the properties to be displayed in a list, tree or table. Columns might also be defined for combo boxes in order to define the columns in the drop list. Other control style types may refer to columns but those will be ignored.

When a field control associated with a control type supporting columns does not define any column, the default column is the access key currently active for the data source.

Columns are field resources an may refer to a field control in order to define sub columns or specific layout information as font or associated image (icon). Layout settings and images apply to the column header, but not to the column content. In order to set layout and image information for data cells in a column, those have to be attached in the ControlContext::doBeforeDataSet() handler.

In order to activate column labels, a label text has to be defined for the column text definition (or the related field control) and show_label has to be set to true. In addition the width ($size.oszwdth) context property may be in order to define exact column width. When column width is set to -1, the size will be determined automatically. When the width is set to 0, the value from the referenced field control context style is used.