Gambas/questions - Revision history

Woozle: that wouldn't even have been a question if the Form properties had been documented. :-P

2015-04-25T17:05:21Z

that wouldn't even have been a question if the Form properties had been documented. :-P

← Older revision		Revision as of 17:05, 25 April 2015
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	==Unanswered==		==Unanswered==
	* How do you get a Label or TextBox control to update its contents?
	** It only seems to update if the Text changes ''after'' the containing form has been moved. Subsequent changes will not appear until after the form moves again.
	* How do you set the text of header cells in a GridView (or TableView)?		* How do you set the text of header cells in a GridView (or TableView)?
	* How do you get a list of selected cells in a GridView (or TableView)?		* How do you get a list of selected cells in a GridView (or TableView)?

Woozle: also TextBox

2015-04-25T16:01:42Z

also TextBox

← Older revision		Revision as of 16:01, 25 April 2015
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	==Unanswered==		==Unanswered==
	* How do you get a Label control to update its contents?		* How do you get a Label or TextBox control to update its contents?
	** It only seems to update if the Text changes ''after'' the containing form has been moved. Subsequent changes will not appear until after the form moves again.		** It only seems to update if the Text changes ''after'' the containing form has been moved. Subsequent changes will not appear until after the form moves again.
	* How do you set the text of header cells in a GridView (or TableView)?		* How do you set the text of header cells in a GridView (or TableView)?

Woozle: another Q, another Q&A

2015-04-25T15:44:35Z

another Q, another Q&A

← Older revision		Revision as of 15:44, 25 April 2015
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	==Unanswered==		==Unanswered==
			* How do you get a Label control to update its contents?
			** It only seems to update if the Text changes ''after'' the containing form has been moved. Subsequent changes will not appear until after the form moves again.
	* How do you set the text of header cells in a GridView (or TableView)?		* How do you set the text of header cells in a GridView (or TableView)?
	* How do you get a list of selected cells in a GridView (or TableView)?		* How do you get a list of selected cells in a GridView (or TableView)?
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	==Solved==		==Solved==
			* '''Q''': How do you call an overridden parent method (function/sub)?
			** '''A''': (tentative) Invoke it as Me.MethodName()
	* The "'''Not an object'''" error can mean that you tried to refer to a property as if it were a function, i.e. followed it with empty parentheses.		* The "'''Not an object'''" error can mean that you tried to refer to a property as if it were a function, i.e. followed it with empty parentheses.
	* Syntax for calling parameterless functions is deceptive. You can sometimes get away without using the parentheses, but other times you will get ''the function itself'' (presumably a pointer of some kind) as the return value instead of executing the funtion. When in doubt, always use parentheses.		* Syntax for calling parameterless functions is deceptive. You can sometimes get away without using the parentheses, but other times you will get ''the function itself'' (presumably a pointer of some kind) as the return value instead of executing the funtion. When in doubt, always use parentheses.
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	** '''Key presses''': use the [[Key object (Gambas)\|Key object]]		** '''Key presses''': use the [[Key object (Gambas)\|Key object]]
	** '''Controls in a group''': use the [[LAST (Gambas)\|LAST]] keyword		** '''Controls in a group''': use the [[LAST (Gambas)\|LAST]] keyword
	*** The most obvious solution would have been for the event to pass the control as a parameter; Gambas events don't seem to use parameters. Another intuitive solution would have been for the group itself to appear on the form's list of controls/methods, as an alias for the currently active/effective control. Finally, if the form had an ActiveControl property, I could pull the .Tag value from there, although I would expect to run into problems using this technique under some circumstances~~. '''Answer''': The LAST keyword refers to the control which generated the current event~~.		*** The most obvious solution would have been for the event to pass the control as a parameter; Gambas events don't seem to use parameters. Another intuitive solution would have been for the group itself to appear on the form's list of controls/methods, as an alias for the currently active/effective control. Finally, if the form had an ActiveControl property, I could pull the .Tag value from there, although I would expect to run into problems using this technique under some circumstances.
	* Another minor thing to remember is that calls to Gambas subroutines always put parentheses around the parameter list (VB subroutines do not, unless the subroutine is a function or property and the return value is being retrieved).		* Another minor thing to remember is that calls to Gambas subroutines always put parentheses around the parameter list (VB subroutines do not, unless the subroutine is a function or property and the return value is being retrieved).
	* '''Q''': How do you open a file-browsing dialog that uses KDE's [[kioslave]] feature? ([http://gambasdoc.org/help/comp/gb.form/dirchooser DirChooser] in gb.form lets you choose a local folder only.)		* '''Q''': How do you open a file-browsing dialog that uses KDE's [[kioslave]] feature? ([http://gambasdoc.org/help/comp/gb.form/dirchooser DirChooser] in gb.form lets you choose a local folder only.)
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	* An "invalid assignment" error can be caused by an undeclared variable, e.g. "A = B" if A has not been declared.		* An "invalid assignment" error can be caused by an undeclared variable, e.g. "A = B" if A has not been declared.
	* Properties cannot accept additional arguments (other than the value being processed or retrieved). Workaround: instead of '''property Value''', have '''function GetValue''' and '''sub PutValue(iVal)'''. Not elegant, but functionally equivalent. Another option may be to have the passed data be a hash, but that is probably only efficient in certain rare circumstances; otherwise it involves extra coding to put the data in the hash and get it back out again.		* Properties cannot accept additional arguments (other than the value being processed or retrieved). Workaround: instead of '''property Value''', have '''function GetValue''' and '''sub PutValue(iVal)'''. Not elegant, but functionally equivalent. Another option may be to have the passed data be a hash, but that is probably only efficient in certain rare circumstances; otherwise it involves extra coding to put the data in the hash and get it back out again.
	* This may be a '''compiler bug''' or at least an undocumented feature: a class with no member variables seems to be automatically classified as "[[static ~~class (Gambas)~~\|static]]", and therefore cannot be used with the NEW operator. To get around the problem, declare a dummy member variable (e.g. "private strDummy as string").		* This may be a '''compiler bug''' or at least an undocumented feature: a class with no member variables seems to be automatically classified as "[[../classes/static\|static]]", and therefore cannot be used with the NEW operator. To get around the problem, declare a dummy member variable (e.g. "private strDummy as string").

Woozle: extracted from main Gambas page; updates, more questions

2013-07-01T16:03:21Z

extracted from main Gambas page; updates, more questions

New page

==Unanswered==
* How do you set the text of header cells in a GridView (or TableView)?
* How do you get a list of selected cells in a GridView (or TableView)?
** The documentation for _GridView_Rows seems to be wrong -- it says there is a "Selection" property, but the compiler says there is no such thing.
* How do you access files shared via [[Samba]]? (One way would be to make use of the smb [[kioslave]]; how is that done in Gambas?)
* Is it possible to do [[continuous forms]] as in [[MS Access]]? It seems likely that it can be done with some coding...
* Is there any Gambas equivalent to the VB line-continuation syntax (space + underscore)?
* Is there a general language syntax tutorial or reference anywhere?
* What do you do when an attempt to get Mouse information (e.g. Mouse.Right, to find out if the right button is being clicked) inside a Click event causes the error message "No mouse event data"? (The message box does not display an error number.)

==Solved==
* The "'''Not an object'''" error can mean that you tried to refer to a property as if it were a function, i.e. followed it with empty parentheses.
* Syntax for calling parameterless functions is deceptive. You can sometimes get away without using the parentheses, but other times you will get ''the function itself'' (presumably a pointer of some kind) as the return value instead of executing the funtion. When in doubt, always use parentheses.
** Where the function returns an object, '''function.method''' seems to be ok (as long as "method" is not also a function)
* One of the more confusing aspects of Gambas (for a Visual Basic user, anyway) is that Gambas's events do not pass parameters; instead, you have to know where to fetch them from:
** '''Form resize''': the size is easily available as a form property ("ME.")
** '''Mouse clicks''': use the [[Mouse object (Gambas)|Mouse object]]
** '''Key presses''': use the [[Key object (Gambas)|Key object]]
** '''Controls in a group''': use the [[LAST (Gambas)|LAST]] keyword
*** The most obvious solution would have been for the event to pass the control as a parameter; Gambas events don't seem to use parameters. Another intuitive solution would have been for the group itself to appear on the form's list of controls/methods, as an alias for the currently active/effective control. Finally, if the form had an ActiveControl property, I could pull the .Tag value from there, although I would expect to run into problems using this technique under some circumstances. '''Answer''': The LAST keyword refers to the control which generated the current event.
* Another minor thing to remember is that calls to Gambas subroutines always put parentheses around the parameter list (VB subroutines do not, unless the subroutine is a function or property and the return value is being retrieved).
* '''Q''': How do you open a file-browsing dialog that uses KDE's [[kioslave]] feature? ([http://gambasdoc.org/help/comp/gb.form/dirchooser DirChooser] in gb.form lets you choose a local folder only.)
** '''A''': [http://gambasdoc.org/help/comp/gb.qt.kde/dialog/selectdirectory Dialog.SelectDirectory] in [http://gambasdoc.org/help/comp/gb.qt.kde gb.qt.kde] provides this.
* An "invalid assignment" error can be caused by an undeclared variable, e.g. "A = B" if A has not been declared.
* Properties cannot accept additional arguments (other than the value being processed or retrieved). Workaround: instead of '''property Value''', have '''function GetValue''' and '''sub PutValue(iVal)'''. Not elegant, but functionally equivalent. Another option may be to have the passed data be a hash, but that is probably only efficient in certain rare circumstances; otherwise it involves extra coding to put the data in the hash and get it back out again.
* This may be a '''compiler bug''' or at least an undocumented feature: a class with no member variables seems to be automatically classified as "[[static class (Gambas)|static]]", and therefore cannot be used with the NEW operator. To get around the problem, declare a dummy member variable (e.g. "private strDummy as string").