Itemid (ScreenField property): Difference between revisions
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{{Template:ScreenField:Itemid subtitle}} | |||
The <var>Itemid</var> property sets or returns a numeric item ID value for a <var>ScreenField</var>. This ID is initially set for a field by the <var>[[AddField_(Screen_function)|AddField]]</var> method. | |||
==Syntax== | ==Syntax== | ||
{{Template:ScreenField:Itemid syntax}} | |||
===Syntax terms=== | ===Syntax terms=== | ||
< | <table class="syntaxTable"> | ||
< | <tr><th>%currentNumber</th> | ||
< | <td>An integral numeric variable or expression, to get the current item id value.</td></tr> | ||
< | |||
</ | |||
<tr><th>sfield</th> | |||
<td>A reference to an instance of a <var>ScreenField</var> object.</td></tr> | |||
<tr><th>newNumber</th> | |||
<td>An integral numeric variable or expression, which can range from 1 to 32767, to set the new item id value.</td></tr> | |||
</table> | |||
An item ID is very practical when using arraylists of screenfields. ScreenField objects within an arraylist can be assigned item IDs corresponding to the element numbers of the arraylist. For example, the [[Screen class#CursorItemId| | ==Usage notes== | ||
<ul><li>Any <var>screenfield</var> can be assigned an item ID. | |||
<li>An item ID is very practical when using <var>[[Arraylist_class|arraylists]]</var> of <var>screenfields</var>. <var>ScreenField</var> objects within an <var>arraylist</var> can be assigned item IDs corresponding to the element numbers of the <var>arraylist</var>. For example, the <var>[[Screen class#CursorItemId|CursorItemId]]</var> method will return the item ID of the <var>screenField</var> object where the cursor is positioned. The item ID can then be used as the element number to reference a <var>ScreenField</var> object within an arraylist. | |||
<li>Any <var>screenField</var> not assigned an item ID value will return zero. No check is made to ensure any item Id is unique. This is the programmer's responsibility. | |||
</ul> | |||
==See also== | |||
{{Template:ScreenField:Itemid footer}} | |||
Latest revision as of 19:41, 20 November 2012
Set or return the item ID value for screenfield (ScreenField class)
The Itemid property sets or returns a numeric item ID value for a ScreenField. This ID is initially set for a field by the AddField method.
Syntax
%currentNumber = sfield:Itemid sfield:Itemid = newNumber
Syntax terms
| %currentNumber | An integral numeric variable or expression, to get the current item id value. |
|---|---|
| sfield | A reference to an instance of a ScreenField object. |
| newNumber | An integral numeric variable or expression, which can range from 1 to 32767, to set the new item id value. |
Usage notes
- Any screenfield can be assigned an item ID.
- An item ID is very practical when using arraylists of screenfields. ScreenField objects within an arraylist can be assigned item IDs corresponding to the element numbers of the arraylist. For example, the CursorItemId method will return the item ID of the screenField object where the cursor is positioned. The item ID can then be used as the element number to reference a ScreenField object within an arraylist.
- Any screenField not assigned an item ID value will return zero. No check is made to ensure any item Id is unique. This is the programmer's responsibility.