TSubForm: what changed
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Title: TSubForm
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| 1 | + | > **Warning:** TSubform and its documentation seem to be unmaintained... | |
| 2 | + | ||
| 3 | + | **TSubForm** is a Data-Aware SubForm | |
| 4 | + | ||
| 5 | + | This component is exactly what it sounds like - a subform component. Use it as you would a TPanel - drop components on it, assign a DataSource and at runtime the magic begins. | |
| 6 | + | ||
| 7 | + | At runtime, all the original components are hidden - Don't Panic! They are duplicated using streams for every record in the DataSource's dataset. If you have added any data-aware components to the component, and their Datasources are set to the same as the component, the duplicates are assigned a new DataSource which maps onto a TMemDataSet. Okay, that sounds nice and complex, but the end result is that the component replicates your controls for every row in the table it's assigned to. | |
| 8 | + | ||
| 9 | + | This means with NO CODE, you can create a customised row (or Column - see the Direction property) layout for any dataset. Assign a very small amount of code to TDBEdit's KeyUp event to check for VK_RETURN and you can even edit it. This is achieved by a BeforePost event on the underlying TMemDataSet. | |
| 10 | + | ||
| 11 | + | #### Bugs/Enhancements | |
| 12 | + | ||
| 13 | + | Well, it's probably pretty easy to make this fall over I would imagine, but it is only 0.1 :-) I really want to make a .Post procedure so you can fire a post to the active memds (and therefore the real DS) but I've run out of debugging time for now. The code is mostly written, just something causes a sigsegv I haven't had time to chase down. | |
| 14 | + | ||
| 15 | + | Thanks : giantm and all the folks on \#lazarus-ide for helping me figure some of the more complex stuff especially RTTI | |
| 16 | + | ||
| 17 | + | Its main caracteristics are : | |
| 18 | + | ||
| 19 | + | - Row or Column per row in the dataset | |
| 20 | + | - Seamless Memory Dataset per row | |
| 21 | + | - Data-Aware components are set to Memory Dataset if set to the same as the component. | |
| 22 | + | - Posts to the Memory Dataset will post back to the DataSource's dataset. | |
| 23 | + | ||
| 24 | + | The download contains the component, an installation package and a demo application, that illustrates the features of the component. | |
| 25 | + | ||
| 26 | + | If you add components to the form that are not in the Standard, Additional or Data Controls pallettes, you will need to write your own OnFindClass procedure as at [[Streaming components|Reading a component from a stream]]. I elected to create a property you can use called CascadeFindClass, so you can decide if to use mine, your own or mine then your own. | |
| 27 | + | ||
| 28 | + | ### Screenshot | |
| 29 | + | ||
| 30 | + | To follow soon. | |
| 31 | + | ||
| 32 | + | ### Author | |
| 33 | + | ||
| 34 | + | ### License | |
| 35 | + | ||
| 36 | + | Your choice of : | |
| 37 | + | ||
| 38 | + | - [GPL](http://www.opensource.org/licenses/gpl-license.php) | |
| 39 | + | - [LGPL](http://www.opensource.org/licenses/lgpl-license.php) | |
| 40 | + | - The modified LGPL that Lazarus is distributed under - see [Lazarus' COPYING.modifiedLGPL](http://svn.freepascal.org/svn/lazarus/trunk/COPYING.modifiedLGPL) | |
| 41 | + | ||
| 42 | + | (please contact the author if the License options above don't work with your project licensing) | |
| 43 | + | ||
| 44 | + | ### Download | |
| 45 | + | ||
| 46 | + | The latest stable release can be found on [Lazarus-ccr's SF.net download page](http://sourceforge.net/project/showfiles.php?group_id=92177&package_id=230010). | |
| 47 | + | ||
| 48 | + | ### Change Log | |
| 49 | + | ||
| 50 | + | - Version 0.1 *Apr 26 2007* | |
| 51 | + | ||
| 52 | + | ### Dependencies / System Requirements | |
| 53 | + | ||
| 54 | + | Requirements : A Bookmarkable DataSet and a DataSource. Note: at least TDBF and TMemDS in current FPC ARE bookmarkable, but appear not to be (.BookMarkValid always returns false even for valid bookmarks). | |
| 55 | + | ||
| 56 | + | Built in Lazarus svn 10988 on Linux, doesn't seem to work on win32 svn10809. | |
| 57 | + | ||
| 58 | + | Status: *Alpha* First Release, works here. | |
| 59 | + | ||
| 60 | + | Issues: Might have issues with AutoInc Fields, as MemDS doesn't implement them | |
| 61 | + | ||
| 62 | + | ### Installation | |
| 63 | + | ||
| 64 | + | - Open the .lpk file in lazarus | |
| 65 | + | - Press the Install button on the Package manager | |
| 66 | + | ||
| 67 | + | ### The *TSubForm* Example Application | |
| 68 | + | ||
| 69 | + | **Installation** | |
| 70 | + | ||
| 71 | + | - Open example/testproject.lpi | |
| 72 | + | - compile | |
| 73 | + | - run | |
| 74 | + | ||
| 75 | + | --- | |
| 76 | + | *From the Free Pascal wiki, page "TSubForm", as it stood on 2023-02-15 after a change by Kai Burghardt, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).* | |
| 77 | + | Category: Components | |
| 78 | + | Category: Databases | |
| 79 | + | Category: Lazarus | |
| 80 | + | Category: Lazarus-CCR | |
| 81 | + | Category: Outdated information |