I'm inserting an item in my common control listview like this:
void InsertRow (HWND hWnd, char *col1, char *col2)
{
LV_ITEM lvItem;
lvItem.mask = 0;
lvItem.iItem = 0;
lvItem.iSubItem = 0;
lvItem.iItem = ListView_InsertItem (hWnd, &lvItem);
lvItem.mask = LVIF_TEXT;
lvItem.pszText = col1;
lvItem.cchTextMax = strlen (lvItem.pszText);
ListView_SetItem (hWnd, &lvItem);
lvItem.iSubItem = 1;
lvItem.pszText = col2;
lvItem.cchTextMax = strlen (lvItem.pszText);
ListView_SetItem (hWnd, &lvItem);
}
and works fine, but it is a pain because the vertical scroll goes back to the top of the list, so if I'm watching an item and call this insert function I lost my view, and have to scroll back manually, making my program impossible to work with.
How ca I prevent this autoscrolling?
I'm programming in C, with the win32 API directly (not MFC).
P.D.: ListView style:
LVS_SINGLESEL | WS_BORDER | WS_TABSTOP | WS_CHILD|WS_VISIBLE|WS_BORDER|WS_VSCROLL|WS_HSCROLL|LVS_REPORT
One way is to get the current top position, insert the new item, and then (programatically) scroll back to the saved top position.
Call ListView_GetItem to get the index of the item you want to watch
Call ListView_EnsureVisible(hWnd, index_you_want_to_watch, TRUE) every time you insert a new row.
If you can switch the ListView to virtual mode (apply the LVS_OWNERDATA style and then use the LVN_GETDISPINFO notification to supply your data to the ListView when requested), then you can use ListView_SetItemCountEx() to add/insert/remove items. It has a LVSICF_NOSCROLL flag to prevent scrolling.
Related
For my Angular JS grid work, I'm using ui-grid rather than ng-grid as ui-grid is meant to be the new version which is purer Angular.
I've got a grid that I'm populating with a http response, and I'm able to select a row (based on finding the record matching a $scope variable value) using the api.selection.selectRow method call.
What I need to do next is scroll the grid to that record.
There's an existing stack overflow question along the same lines that is for ng-grid and the answer to that refers to undocumented features which are not present in ui-grid so I can't use that approach.
The closest I've got is finding $scope.gridApi.grid to get a reference to the actual grid itself but looking through the properties and methods in the Chrome debugger doesn't show anything that sounds like it could work.
You can use the cellNav plugin. You should already have a reference to your row entity from the selection. The documentation is here.
gridApi.cellNav.scrollTo(grid, $scope, rowEntity, null);
I managed to hack together something that works pretty well but it's a bit dodgy and could probably be cleaner with a bit more Angular/jquery understanding.
I used the browser dom explorer to find that the scrollbars have a css class that we can detect to find them and then set the scroll properties on them to have the grid scroll (the grid and scrollbars are separate divs but their properties are bound so changing one updates the other).
It doesn't completely work for scrolling to the last row of the grid. This could be a timing issue, I've noticed when using breakpoints that the grid comes on screen a little larger and then shrinks down to it's final size. This could be messing with the scrolling values.
The first loop finds the height of the grid by adding up the rows, and the y position of the row for my data object (project), then we find the scrollbar and set it's scrollTop, trying to centre the row on screen without going out of bounds.
var grid = $scope.projectsGridApi.grid;
// var row = grid.rowHashMap.get(project.$$hashKey);
var found = false;
var y = 0;
var totalY = 0;
var rowHeight = 0;
for (var rowIdx in grid.rows)
{
var row = grid.rows[rowIdx];
if (row.entity.$$hashKey == project.$$hashKey)
{
found = true;
rowHeight = row.height;
}
if (!found)
{
y += row.height;
}
totalY += row.height;
}
// now find the scroll bar div and set it's scroll-top
// (todo: checking if we're at the end of the list - setting scrollTop > max means it doesn't work properly
var grid = $scope.projectsGridApi.grid;
// annoyingly this is nastily coded to find the scrollbar and isn't completely right
// I think the grid is a little taller when this is called, then shrinks
// which affects what the maximum is (so we might not always be able to put the selected item on screen if it is the last one).
var holderDiv = $('#projectsGridHolder');
if (holderDiv)
{
var scrollBarDivs = holderDiv.find('.ui-grid-native-scrollbar');
if (scrollBarDivs)
{
for (var scrollBarDivIdx in scrollBarDivs)
{
var scrollBarDiv = scrollBarDivs[scrollBarDivIdx];
var scrollBarDivClass = scrollBarDiv.className;
if (scrollBarDivClass)
{
if (scrollBarDivClass.indexOf('vertical') != -1)
{
var scrollHeight = scrollBarDiv.scrollHeight;
var clientHeight = scrollBarDiv.clientHeight;
if (rowHeight > 0)
{
y -= (clientHeight - rowHeight) / 2; // center on screen be scrolling slightly higher up
}
if (y < 0) y = 0;
else if (y > totalY - clientHeight) y = totalY - clientHeight;
scrollBarDiv.scrollTop = y;
}
}
}
}
}
I have 10 comboBox in a groupBox
for I just want to display a calculated value in respective comboBox like this say if I set a varible double i=08.00; then on button click cmboBox should display values like this
CB1-08.00
CB2-09.50
CB3-10.00
CB4-10.50
CB5-11.00
CB6-11.50
.... and so on upto CB10 But I am getting output like this
And Code
private void button1_Click(object sender, EventArgs e)
{
double i=08.00;
foreach (var comboBox in groupBox1.Controls.OfType<ComboBox>())
{
comboBox.Text = i.ToString("00.00");
i = i + 0.5;
}
}
Your combobox order is different in the collection so it inserts the numbers randomly. May be you can name your combobox for instance like cmb1,cmb2,cmb3 etc. and if you update your code it will run.
Your controls in the Controls collection are not sorted by their appearance on the form. You will need to find a way to sort them if you need different values in each based on their position.
Foreach loop doesn't give the collection in the order you wanted. The way to go forward is to give a tag id to each combo box, then you can use that to assign a value to them them.
So your first combo box will start with tag id 0, and the last one will have 8,
double val = 08.00;
for (int i = 0; i < groupBox1.Controls.Count; ++i)
{
var combobox = groupBox1.Controls[i] as ComboBox;
int tag = int.Parse(combobox.Tag.ToString());
double value = val + (0.5 * tag);
combobox.Text = value.ToString("00.00");
}
Make sure you tag the cobbo box in the order you wanted them.
I'm using a Listbox wrapped inside a ListBoxDragDropTarget (from the Silverlight toolkit).
This ListBox ca be manually reordered by the user. However the last item must always be located at the bottom of the ListBox, and can't be moved at all. I found a way to cancel this last item moves, but if I drag and drop another item below this last item, it gets moved.
I can find the index of the dragged item using this code in the Drop event of the ListBox:
object data = e.Data.GetData(e.Data.GetFormats()[0]);
ItemDragEventArgs dragEventArgs = data as ItemDragEventArgs;
SelectionCollection selectionCollection = dragEventArgs.Data as SelectionCollection;
if (selectionCollection != null)
{
MyClass cw = selectionCollection[0].Item as MyClass;
int idx = selectionCollection[0].Index.Value;
}
However this only gives me the index before the drag operation.
My question is the following: Is there a way to know the new index of the dropped item ? This way, if the index = last position of the list, I can move it to the forelast position.
Thanks in advance !
Ok I found a way to do this. I bound the ItemDragCompleted event of the ListBoxDragDropTarget, and did the following:
private void dropTarget1_ItemDragCompleted(object sender, ItemDragEventArgs e)
{
var tmp = (e.DragSource as ListBox).ItemsSource.Cast<MyClass>().ToList();
SelectionCollection selectionCollection = e.Data as SelectionCollection;
if (selectionCollection != null)
{
MyClass cw = selectionCollection[0].Item as MyClass;
int idx = tmp.IndexOf(cw);
if (idx == tmp.Count - 1)
{
tmp.Remove(cw);
tmp.Insert(tmp.Count - 1, cw);
MyListBox.ItemsSource = new ObservableCollection<MyClass>(tmp);
}
}
}
As the DragSource represents the Listbox, with the new "arrangement" of items, I can therefore check if the item is now located at the end, and move it in this case.
The only problem left is that it causes a flicker on the screen, due to the item being dropped and then moved.
I'm still open to any other (best) suggestion.
I have this exact same problem. I think it may be possible to loop through the rectangles of the items in the ListBox and see if var point = args.GetPosition(myListBox); is within them. But I am hoping for an easier way...
Edit: The problem with this though, is you don't get the gravity effect that is already built in to silverlight where only half of the above and half of the below rectangle are used to drop it into the list.
This article shows how to implement a copy operation on a drop event. I'd like to do the same but I want my dropped item to appear in the collection according to where it was placed on the UI. So I need the StartIndex much like on a NotifyCollectionChangedEventArgs when an ObservableCollection changes. In the article you'll see that eventually you get a SelectionCollection object whose items have an Index property. But unfortunately this is the index of the source collection (where it was picked) and not the destination collection (where it was dropped).
Ok, this is quite ugly, but I didn't find another way, not by myself and also not by searching the net for answers. Must have been another deadline at Microsoft that prevented the rather obvious functionality to be included...
Basically the method below does everything manually, getting the drop location and checking it for listbox items to use as index references.
private void ListBoxDragDropTarget_Drop(object sender, Microsoft.Windows.DragEventArgs e)
{
// only valid for copying
if (e.Effects.HasFlag(DragDropEffects.Copy))
{
SelectionCollection selections = ((ItemDragEventArgs)e.Data.GetData("System.Windows.Controls.ItemDragEventArgs")).Data as SelectionCollection;
int? index = null;
if (selections != null)
{
Point p1 = e.GetPosition(this.LayoutRoot); // get drop position relative to layout root
var elements = VisualTreeHelper.FindElementsInHostCoordinates(p1, this.LayoutRoot); // get ui elements at drop location
foreach (var dataItem in this.lbxConfiguration.Items) // iteration over data items
{
// get listbox item from data item
ListBoxItem lbxItem = this.lbxConfiguration.ItemContainerGenerator.ContainerFromItem(dataItem) as ListBoxItem;
// find listbox item that contains drop location
if (elements.Contains(lbxItem))
{
Point p2 = e.GetPosition(lbxItem); // get drop position relative to listbox item
index = this.lbxConfiguration.Items.IndexOf(dataItem); // new item will be inserted immediately before listbox item
if (p2.Y > lbxItem.ActualHeight / 2)
index += 1; // new item will be inserted after listbox item (drop location was in bottom half of listbox item)
break;
}
}
if (index != null)
{
foreach (var selection in selections)
{
// adding a new item to the listbox - adjust this to your model
(lbxConfiguration.ItemsSource as IList<ViewItem>).Insert((int)index, (selection.Item as ViewItem).Clone());
}
}
}
}
}
My target: a DocumentPaginator which takes a FlowDocument with a table, which splits the table to fit the pagesize and repeat the header/footer (special tagged TableRowGroups) on every page.
For splitting the table I have to know the heights of its rows.
While building the FlowDocument-table by code, the height/width of the TableRows are 0 (of course). If I assign this document to a FlowDocumentScrollViewer (PageSize is set), the heights etc. are calculated. Is this possible without using an UI-bound object? Instantiating a FlowDocumentScrollViewer which is not bound to a window doesn't force the pagination/calculation of the heights.
This is how I determine the height of a TableRow (which works perfectly for documents shown by a FlowDocumentScrollViewer):
FlowDocument doc = BuildNewDocument();
// what is the scrollviewer doing with the FlowDocument?
FlowDocumentScrollViewer dv = new FlowDocumentScrollViewer();
dv.Document = doc;
dv.Arrange(new Rect(0, 0, 0, 0));
TableRowGroup dataRows = null;
foreach (Block b in doc.Blocks)
{
if (b is Table)
{
Table t = b as Table;
foreach (TableRowGroup g in t.RowGroups)
{
if ((g.Tag is String) && ((String)g.Tag == "dataRows"))
{
dataRows = g;
break;
}
}
}
if (dataRows != null)
break;
}
if (dataRows != null)
{
foreach (TableRow r in dataRows.Rows)
{
double maxCellHeight = 0.0;
foreach (TableCell c in r.Cells)
{
Rect start = c.ElementStart.GetCharacterRect(LogicalDirection.Forward);
Rect end = c.ElementEnd.GetNextInsertionPosition(LogicalDirection.Backward).GetCharacterRect(LogicalDirection.Forward);
double cellHeight = end.Bottom - start.Top;
if (cellHeight > maxCellHeight)
maxCellHeight = cellHeight;
}
System.Diagnostics.Trace.WriteLine("row " + dataRows.Rows.IndexOf(r) + " = " + maxCellHeight);
}
}
Edit:
I added the FlowDocumentScrollViewer to my example. The call of "Arrange" forces the FlowDocument to calculate its heights etc. I would like to know, what the FlowDocumentScrollViewer is doing with the FlowDocument, so I can do it without the UIElement. Is it possible?
My guess would be no, you can't do it without a UIElement.
FlowDocument, by itself, doesn't actually render anything. Looking at the type in relector it looks like it is just a data type. Its about like having a string and wanting to know its size when rendered ... can't really do it without doing some kind of measure pass.
I don't know for sure, but you might get better performance in the arrange pass by passing in Double.PositiveInfinity for the size rather than 0. At least then it won't have to worry about measuring 'n' line breaks.