I am creating images dynamically in BIRT and adding them to a cell of a grid. The grid is part of a List, which iterates over the records in the data source.
I want to be able to modify the properties of the images on a per-record basis. Specifically I am changing the margins - but my problem is that I cannot find the way to access the contents of the cell.
I expected that I could use the 'this' keyword in the cell's onRender function and it would provide me a handle to access the cell's contents.
This function does not seem to work though - it is apparently a different object type.
How do I access the children of an individual instance of a cell?
Related
upon construction of QTreeWidgetItem you can pass a list of strings, so when you insert it in a table(QTreeWidget), you get the strings listed on a row. However, from the methods of the table you can also call setItemWidget and set a text widget or any sort of widget to be in that row, but it seems incompatible with having a string list, since the widget is drawn over the strings. There is also a setData method for the QTreeWidgetItem, which sets some data that can be retreived, but isn't visible to the user. Is there a cookie-cutter way of properly using all three data storage methods? Are they even compatible or must I stick to only one?
The Constructor of QTreeWidgetItem is convenient to immediately list the desired content.
When inserting a custom widget in a cell, you need to change its autoFillBackgroundproperty to true, so that it is not transparent. See the QTreewidget::setItemWidget description:
The given widget's autoFillBackground property must be set to true,
otherwise the widget's background will be transparent, showing both
the model data and the tree widget item.
QTreeWidgetItem::setData can be used when already having an item and you want to change one of its contents.
Of course you can combine any of these methods, but it is hard to say, which approach is best without knowing your use case. Just one more hint: If you just need a plain stupid representation of data that does not change, using QTreeWidget is fine. But if your displayed data can change, e.g. objects get deleted, added, changed in various locations of your code, a QTreeView with a custom data model might be a better choice.
I have a situation where I'm using the IEditorDataFilter interface within a custom UltraGrid editor control to automatically map values from a bound data source when they're displayed in the grid cells. In this case it's converting guid-based key values into user-friendly values, and it works well by displaying what I need in the cell, but retaining the GUID values as the 'value' behind the scenes.
My issue is what happens when I enable the built-in group by functionality and the user groups by a column using my editor. In that case the group by headers default to using the cell's value, which is the guid in my case, so I end up with headers like this:
Column A: 7F720CE8-123A-4A5D-95A7-6DC6EFFE5009 (10 items)
What I really want is the cell's display value to be used instead so it's something like this:
Column A: Item 1 (10 items)
What I've tried so far
Infragistics provides a couple mechanisms for modifying what's shown in group by rows:
GroupByRowDescriptionMask property of the grid (http://bit.ly/1g72t1b)
Manually set the row description via the InitializeGroupByRow event (http://bit.ly/1ix1CbK)
Option 1 doesn't appear to give me what I need because the cell's display value is not exposed in the set of tokens they provide. Option 2 looks promising but it's not clear to me how to get at the cell's display value. The event argument only appears to contain the cell's backing value, which in my case is the GUID.
Is there a proper approach for using the group by functionality when you're also using an IEditorDataFilter implementation to convert values?
This may be frowned upon, but I asked my question on the Infragistic forums as well, and a complete answer is available there (along with an example solution demonstrating the problem):
http://www.infragistics.com/community/forums/p/88541/439210.aspx
In short, I was applying my custom editors at the cell level, which made them unavailable when the rows were grouped together. A better approach would be to apply the editor at the column level, which would make the editor available at the time of grouping, and would provide the expected behavior.
I'm currently trying to apply a filter to the wxCheckListBox (for a search of specific elements). So far i have no idea how to do it. The Problem with it is, that I don't want to have a copy of the Control and always delete the unnecessary items from the copy, and as soon as the search changes it has to be copied again from the original and delete the items again. I was wondering if there is a way to simply hide some items and not the entire control
You can't hide the items in a wxListBox or wxCheckListBox. To have this sort of dynamic control over the items appearing in the control you need to use wxListCtrl in virtual mode.
However it's not usually really a problem to delete some items from a wxListBox and then insert them back (or, even simpler, store all the items, delete some of them from the control and then, to revert, clear the control and restore all the initially stored items).
This question is to understand how to update any row programatically.
Details.
I have a listcrtl, that accepts the data from either from a file or from the edit controls in the dialog. When the items are added I will know its position, that I added, so I can change its subitem texts. I have even implemented the sort functionality in the list, so now the position keeps changing. I have an identifier column for each row, so that I can recognize the row.
Now, from an out side event, if I have to change an other columns value of an ID that I know , I have to first find the position of the item by comparing the id column, then with that position, I have set the subitemtext.
This works fine except that it takes time to find the row first then it need to update the column.
Now, in order to get the row directly, I need some help.
I have gone through
http://msdn.microsoft.com/en-us/library/windows/desktop/hh298346(v=vs.85).aspx
But this does not use MFC. Please help me achieving this.
If you have many items you should consider switching to Virtual Lists. It is the fastest way to access the data. If you do not want to invest time to this, then the easiest way for you will be the following:
When you populate the CListCtrl store the ID of each item in the item data using the SetItemData() method. The ID will always be associated with the item, even after re-sorting.
When you need to locate the required item, just scan all items, but do not use GetItemText(). Use GetItemData() instead. This will be faster
I am using a List Control to display a representation of elements within a vector. When the list is clicked on another control shows information about that element. The index of the element is currently determined by its index in the control, however if I wish to sort or filter the results this will no longer work.
I have been told that I could use a virtual list control, but the MSDN is not very friendly, can someone run me through how I could use a virtual list control for this?
Frankly - tying data (the position in your data vector) to the presentation of the data in the list control (the position in the list ctrl) is something I would stay away from.
In MFC each control has a "Data" DWORD member variable - when coding in MFC I Always called "SetItemData" for each item added and passed in a pointer that the relevant row referred to e.g.
YourListCtrl.SetItemData((DWORDPTR)&YourData);
Then when the ListCtrl item is selected, you just call
DataTypeYouWant* pData = (DataTypeYouWant*)(YourListCtrl.GetItemData(indexofselecteditem));
Or somesuch thing.
Alternatively - if you don't want to use pointers - hold the index of the item in your original vector in the itemdata for your row (just pass it into the above fns).
To use a virtual list control, set the LVS_OWNERDATA style. You then need to handle the LVN_GETDISPINFO notification message (which is sent via WM_NOTIFY).
If you do this, you are entirely responsible for the data, including the order in which it is shown. Therefore it is up to you to handle sorting and so forth.
By far the easiest way is just to use the item data to set/get an ID that can be used to retrieve the original data, whether that's a vector index or a pointer to the data, or even a key into an associative container.
It really depends on the performance you require.
I have personally seen MAJOR increases in performance for lists holding massive amount of data. However it is much more work to implement, thus for simple uses with not so many data I recommend staying away from it.
Basically, what happens with virtual list controls is that you have your data somewhere in some data structure of your own. Since the list view shows only a small subset of the whole data, it queries you for the content to display when ever something happens (redraw necessary, scroll up or down, change the sorting, etc.).
I don't have handy examples for you. But you can look on codeguru, I am quite sure there are very good examples to start from.
The purpose of virtual list controls is totally different: You should use it for performance reason when you have A LOT of items in your list (I'd say 2500+).
In your case, all you need is to store the vector index in the list item data as NotJarvis explains.