Difference between revisions of "TListView"
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'''SortType''' is the key property in order to perform any sorting in TListView. | '''SortType''' is the key property in order to perform any sorting in TListView. | ||
:'''stNone''' - (the default value) that no sorting should be for the control. | :'''stNone''' - (the default value) that no sorting should be for the control. | ||
| + | :'''stText''' - the text of a cells would be used for item comparison. The actual text entry is controlled by '''SortColumn''' property. Note the default sorting comparison is actually treats the text as Ansi, rather than UTF8. Thus the result might be undesired for the non-English texts | ||
| + | :'''stData''' - the default sorting comparison treats '''Data''' property as an integer value (by casting pointer to an integer) and sorts the according to value. (in most cases such sorting is useless, unless "Data" is an actual integer casted to the pointer) | ||
| + | :'''stBoth''' - treated as '''stText''' for in the default sorting comparison. | ||
Revision as of 18:00, 9 January 2020
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TListView 
is a visible component on the Common Controls tab of the Component Palette that provides a list view of its associated Items. Items can be represented by an icon from each of the associated TImageLists: SmallImages, LargeImages and StateImages.
Notes
- GetNextItem() requires StartItem to be provided. This is incompatible with Delphi's GetNextItem(), where startItem is allowed to be nil, which will perform the search from the relative (direction driven) start.
Sorting
Sorting is (typically?) applied when using vsReport ViewStyle. Sorting might be a time consuming process or a larger data scale (when comparison of items takes a considerable time).
SortType is the key property in order to perform any sorting in TListView.
- stNone - (the default value) that no sorting should be for the control.
- stText - the text of a cells would be used for item comparison. The actual text entry is controlled by SortColumn property. Note the default sorting comparison is actually treats the text as Ansi, rather than UTF8. Thus the result might be undesired for the non-English texts
- stData - the default sorting comparison treats Data property as an integer value (by casting pointer to an integer) and sorts the according to value. (in most cases such sorting is useless, unless "Data" is an actual integer casted to the pointer)
- stBoth - treated as stText for in the default sorting comparison.
Typically the sorting can be requested by a user. Whenever a user clicks on a column header, that requires to either sort (initially ascendancy) or to switch to the opposite sorting order (either from ascendant to descendant, or back). It's not a rule, but a common expectation. For some data sets selecting sorting might not make any sense. AutoSort (default value is true)the property of TListview controls, if the listview should be sorted automatically, as soon as user clicks on a column header. AutoSort will have no effect, while SortType is set to stNone.
AlphaSort is a convenience method, that changes the settings to ascending sort (SortDirection=sdAscending) based on the text (SortType=stText) of the first column (SortColumn=0). Note that the actual properties are changed.
See also
