I have two choices, one of them set Choices to another one when I select an option.
When I select an option, I calling in fieldChanged method a function that set new options to another ObjectChoiceField depending the selected option.
The problem is that the scroll decreases its height or the screen loses height and some fields at the bottom are hidden.
Please, any idea?
Thanks in advance.
Related
I have a THorzScrollBox in a form, and some TStyledControls inside. Each StyledControl has a Tag to identify. Using an TEdit to inform a value, I can find inside the ScrollBox an specific Control by his tag.
If the control that I searched is not on the screen, I want to scroll the ScrollBox to show it.
How can I do this programmatically?
I found a way to do this.
I have to use ScrollBy. But the detail is that if I want to scroll the controls to right I have to use a negative value.
Example:
sbItems.ScrollBy(-10, 0); // this will scroll to right
If I use a positive value, it will scroll to left.
sbItems.ScrollBy(10, 0); // this will scroll to left
The point is, if you scroll once, the ViewportPosition will change and the next time you execute ScrollBy, it will not reset the scroll position, it will scroll from the point you already have scrolled.
I am using the VirtualTreeView together with the OnMeasureItem event to display rows of variable size. The problem is that the event seems to be called only if a row is painted (following the virtual paradigm). But this leads to the scrollbar being displayed incorrectly. If I scroll to the bottom (by dragging the scrollbox with the mouse, not clicking the scroll buttons at the top or bottom), not the last row is displayed (which is what I would expect), but some row in the middle. After that, the scrollbar is updated and I can scroll further down. It seems as if the component uses the DefaultNodeHeight for its scrolling calculations. But since my rows have variable height, I cannot specify a DefaultNodeHeight that would lead to correct results. Option toVariableNodeHeight is enabled.
Has anyone experienced this before and maybe found a workaround? Or am I doing it wrong?
You need to set DefaultNodeHeight to the maximum value you will be using and OnMeasureItem event set custom height value for the current node. Similar issue was described here.
In the ListField,If i click on selected index or focus on the selected index,i want to chane the height of the selected field automatically....
Can u help how to implement that ....
Advance thanks..
A ListField can only have uniform row sizes, so unfortunately it won't be something as simple as changing the height of the selected row. If you're wanting it to be able to change sizes, you'll probably need to write your own. It wouldn't be too terribly difficult by just adding fields to a VerticalFieldManagerand making that scrollable, though you will need to handle selection painting, row indexing, etc.
A ListField can only have uniform row sizes... but if you use horizontalFieldManager for the list row. you can change the size on TouchEvent by setting height of the horizontalFieldManager
I have a DBGrid on a form. The DBGrid has many columns, so an horizontal scroller is displayed. I scroll the DBGrid view to the right to see more columns. If I select a row, the DBGrid view is automatically reset to view the first column (As if I scroll back to the left most position).
Is there a way to prevent that?
I assume you have goRowSelect in the grid options. This forces the selected col to be the first non-fixed column, so whenever the row changes the code to scroll the selected cell into view forces the first non-fixed column to be visible.
Since goRowSelect also effectively disables the horizontal scrolling with the keyboard I try to live without it. You can use custom drawing of the grid cells to show all cells of the current row with the proper colours for selected cells, even though only one cell is really selected. I use this also to show different colours depending on whether the grid is focused or not, similar to what a standard tree control does. For this to work properly you do however need to handle not only grid cell navigation events, but some other events too, like OnEnter and OnExit of the grid, OnActivate and OnDeactivate of the Application, and so on.
You might be able to ask for the scrollbar position
GetScrollInfo(Self.Handle, SB_VERT, SIOld);
and use SetScrollInfo( ) to put it back. There's probably a better way. SelectedField is another way (get/set it as needed).
I have a DBGrid on a form. The DBGrid has many columns, so an horizontal scroller is displayed. I scroll the DBGrid view to the right to see more columns. If I select a row, the DBGrid view is automatically reset to view the first column (As if I scroll back to the left most position).
Is there a way to prevent that?
I assume you have goRowSelect in the grid options. This forces the selected col to be the first non-fixed column, so whenever the row changes the code to scroll the selected cell into view forces the first non-fixed column to be visible.
Since goRowSelect also effectively disables the horizontal scrolling with the keyboard I try to live without it. You can use custom drawing of the grid cells to show all cells of the current row with the proper colours for selected cells, even though only one cell is really selected. I use this also to show different colours depending on whether the grid is focused or not, similar to what a standard tree control does. For this to work properly you do however need to handle not only grid cell navigation events, but some other events too, like OnEnter and OnExit of the grid, OnActivate and OnDeactivate of the Application, and so on.
You might be able to ask for the scrollbar position
GetScrollInfo(Self.Handle, SB_VERT, SIOld);
and use SetScrollInfo( ) to put it back. There's probably a better way. SelectedField is another way (get/set it as needed).