GetCharacterRect sometimes gives wrong rect - wpf

I have a UserControl that has a FlowDocument on it.
when I create an object of it, I add load event and after that I add it to a StackPanel.
ViewCell cell = new ViewCell();
cell.Loaded += Cell_Loaded;
sp_Texts.Children.Add(cell);
private void Cell_Loaded(object sender, RoutedEventArgs e)
{
foreach (var item in sp_Texts.Children)
{
double y = (item as ViewCell).GetYPosition();
...
return;
}
}
In Cell_Loaded I want to know rect of some words in FlowDocument in ViewCell. sometimes it gives me correct answer, but sometimes it gives me infinity because textpointer has not a valid layout.
public double GetYPosition()
{
TextPointer startpos;
...
var verticalScrollPos = startPos.GetCharacterRect(LogicalDirection.Forward).Y;
return verticalScrollPos ;
}

Related

How to Raise DragDelta event on Thumb

As you can see below, I want to start moving when the component visibility changes.
because otherwise I need the user to click again to start the movement, and that is bad in terms of usability for my application.
public MoveILayoutControl()
{
InitializeComponent();
this.IsVisibleChanged += new DependencyPropertyChangedEventHandler(MoveILayoutControl_IsVisibleChanged);
this.moveThumb.DragDelta += new DragDeltaEventHandler(MoveThumb_DragDelta);
}
void MoveILayoutControl_IsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if (this.IsVisible)
{
// Raise Drag Event !?
}
}
private void MoveThumb_DragDelta(object sender, DragDeltaEventArgs e)
{
var myData = DataContext as ILayoutVisual;
if (myData != null)
{
Point dragDelta = new Point(e.HorizontalChange, e.VerticalChange);
if (myData.Rotation != 0)
{
Matrix toCalculate = ((this.Parent as FrameworkElement).RenderTransform).Value;
if (toCalculate != null)
{
dragDelta = toCalculate.Transform(dragDelta);
}
}
myData.X += dragDelta.X;
myData.Y += dragDelta.Y;
}
}
I believe the only way is using reflection to change the internal values ​​of the thumb. Changing the property "IsDragging" (not tested).
I looked up the source code of Thumb and I think a better way is to simulate a MouseLeftButtonEvent on the thumb:
var evt = new MouseButtonEventArgs(mouseDevice, timestamp, MouseButton.Left)
{
RoutedEvent = UIElement.MouseLeftButtonDownEvent
};
thumb.RaiseEvent(evt);

How can I find UIElements in a rectangle in WPF?

I need to find UIElements in (rectangle/area/bounds).
MainWindow I'm doing the following:
I register the mouse down as the start position.
I regsiter the mouse up position.
Now I need to find ll (buttons, textboxes, etc) in the rectangle between start
postion and the end position.
I found in the msdn the HitTest approach but it is only for one point. I think, walking through all points in the founded
rectangle it is a performance disaster.
http://msdn.microsoft.com/en-us/library/ms752097.aspx
My code based on MVVM pattern:
private ObservableCollection<UIElementViewModel> wells;
private Point stratPoint; // Mouse down
public ICommand MouseUpRightCommand
{
get
{
if (this.mouseUpRightCommand == null)
{
this.mouseUpRightCommand = new RelayCommands(
param =>
{
if (param is MouseButtonEventArgs)
{
var e = (param as MouseButtonEventArgs);
//Set the end point
endPosition = e.GetPosition(((ItemsControl)e.Source));
// for example, here I want to find all controls(UIElements) in the
// founded rectangle of stratPoint and endPosition.
}
});
}
return this.mouseUpRightCommand;
}
}
Any other idea or a better approach?
Thanks
I would use FrameworkElement (which extends UIElement) instead of UIElement, in order to use ActualWidth and ActualHeight properties
Then create a static class which does some math MouseUtils
with those static fields
private static double _dContainerTop;
private static double _dContainerBottom;
private static double _dContainerLeft;
private static double _dContainerRight;
private static double _dCursorTop;
private static double _dCursorLeft;
private static double _dCursorRight;
private static double _dCursorBottom;
and those static methods
private static void FindValues(FrameworkElement element, Visual rootVisual)
{
var containerTopLeft = container.TransformToAncestor(rootVisual).Transform(new Point(0, 0));
_dContainerTop = containerTopLeft.Y;
_dContainerBottom = _dContainerTop + container.ActualHeight;
_dContainerLeft = containerTopLeft.X;
_dContainerRight = _dContainerLeft + container.ActualWidth;
}
and
public static bool IsElementUnderRectCursor(FrameworkElement element, Point startPoint, Point endPoint, Visual rootVisual)
{
_dCursorTop=Math.Min(startPoint.Y, endPoint.Y);
_dCursorBottom=Math.Max(startPoint.Y, endPoint.Y);
_dCursorLeft=Math.Min(startPoint.X, endPoint.X);
_dCursorRight=Math.Max(startPoint.X, endPoint.X);
FindValues(container, rootVisual);
if (_dContainerTop < _dCursorTop|| _dCursorBottom< _dContainerBottom )
{
return false;
}
if (_dContainerLeft < _dCursorLeft|| _dContainerRight < _dCursorRight)
{
return false;
}
return true;
}
Rootvisual being your window for example;
Then loop over ObservableCollection<FrameworkElement> wells and call that function IsElementUnderRectCursor.
This is inspired from:
Kinecting the Dots
Astreal thanks again for your answer. It's done. I just moved the selection code from modelView to view. The selection done only in the UI.
private void SelectWells(RectangleGeometry selectionRectangle, FrameworkElement frameworkElement)
{
var items = GetItemsControl(frameworkElement);
foreach (var item in items.Items)
{
var viusalItem = (ContentPresenter)items.ItemContainerGenerator.ContainerFromItem(item);
var wellControl = this.GetWellControl(viusalItem);
var relativePoint = wellControl.TransformToAncestor(items).Transform(new Point(0, 0));
var controlRectangle =
new RectangleGeometry(
new Rect(relativePoint.X, relativePoint.Y, wellControl.ActualWidth, wellControl.ActualHeight));
var intersectionGeometry = Geometry.Combine(
selectionRectangle, controlRectangle, GeometryCombineMode.Intersect, null);
if (intersectionGeometry.GetArea() > 0)
{
wellControl.Command.Execute(this);
}
}
}
usefull link for u:
http://www.codeproject.com/Articles/354853/WPF-Organization-Chart-Hierarchy-MVVM-Application
When an user clicks on a node in the tree we need to let the ViewModel node know that the selection has changed. We like to route the event as a command to the ViewModel

WPF DataGrid doesn't shrink when column width shrinks

I am using a DataGrid in WPF and want it to shrink to only fit the width of its columns. It does this nicely for the initial rendering. When I resize a column to make it wider the grid grows as well. But if I resize the column to make it narrower again I get white space on the right side of my column (and I can see that the column header grey area is extended beyond the columns.
I would like to have the data grid shrink its width with the columns so I don't get the white space on the right. I have tried to debug the code and as far as I can see the problem is in the DataGridCellsPanel, but I can't see anyplace to fix the width measurement.
Any help would be appreciated.
I had that problem to a while back and I was getting so annoyed by it that I made an ugly fix for it. It's not pretty, but it gets the job done. First, this is only a problem when the Horizontal ScrollBar is invisible so we're gonna need a reference to it. This code will have to be run once all DataGridColumns have been loaded (in my case, all in Xaml, so the Loaded event) and it doesn't take adding/removing of DataGridColumns into consideration but that's an easy fix.
<DataGrid Name="c_dataGrid"
Loaded="c_dataGrid_Loaded"
...>
<DataGrid.Columns>
<DataGridTextColumn ..."/>
<DataGridTextColumn ..."/>
<!-- ... -->
Then in the Loaded EventHandler we get the DataGrid ScrollViewer and add a listener for changes in the ActualWidthProperty of every DataGridColumn in the DataGrid.
private ScrollViewer m_dataGridScrollViewer = null;
private void c_dataGrid_Loaded(object sender, RoutedEventArgs e)
{
m_dataGridScrollViewer = GetVisualChild<ScrollViewer>(c_dataGrid);
DependencyPropertyDescriptor dependencyPropertyDescriptor =
DependencyPropertyDescriptor.FromProperty(DataGridColumn.ActualWidthProperty, typeof(DataGridColumn));
if (dependencyPropertyDescriptor != null)
{
foreach (DataGridColumn column in c_dataGrid.Columns)
{
dependencyPropertyDescriptor.AddValueChanged(column, DataGridColumn_ActualWidthChanged);
}
}
}
And then we compute the size of the DataGrid from the size of all DataGridColumns and add a constant of 8.0 (which is the difference normally).
private void DataGridColumn_ActualWidthChanged(object sender, EventArgs e)
{
if (m_dataGridScrollViewer != null)
{
if (m_dataGridScrollViewer.ComputedHorizontalScrollBarVisibility != Visibility.Visible)
{
double dataGridWidth = 8.0;
foreach (DataGridColumn column in c_dataGrid.Columns)
{
dataGridWidth += column.ActualWidth;
}
c_dataGrid.Width = dataGridWidth;
}
else
{
c_dataGrid.Width = double.NaN;
}
}
}
If you come up with a better way of doing this then let me know :)
public static T GetVisualChild<T>(object parent) where T : Visual
{
DependencyObject dependencyObject = parent as DependencyObject;
return InternalGetVisualChild<T>(dependencyObject);
}
private static T InternalGetVisualChild<T>(DependencyObject parent) where T : Visual
{
T child = default(T);
int numVisuals = VisualTreeHelper.GetChildrenCount(parent);
for (int i = 0; i < numVisuals; i++)
{
Visual v = (Visual)VisualTreeHelper.GetChild(parent, i);
child = v as T;
if (child == null)
{
child = GetVisualChild<T>(v);
}
if (child != null)
{
break;
}
}
return child;
}
That's a nice solution. I have tweaked it slightly so that it sets the MaxWidth property instead. This solves the problem of the grid expanding beyond the constraints of the visual parent. I also converted it into a behavior instead in order to encapsulate it better.
This is what I ended up with.
public class UpdateWidthOnColumnResizedBehavior : Behavior<DataGrid>
{
private static readonly DependencyPropertyDescriptor Descriptor;
static UpdateWidthOnColumnResizedBehavior()
{
Descriptor = DependencyPropertyDescriptor.FromProperty(DataGridColumn.ActualWidthProperty, typeof(DataGridColumn));
}
protected override void OnAttached()
{
base.OnAttached();
AssociatedObject.Columns.CollectionChanged += OnColumnsCollectionChanged;
foreach (var column in AssociatedObject.Columns)
{
AddListener(column);
}
}
void OnColumnsCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
foreach (var column in e.NewItems.OfType<DataGridColumn>())
{
AddListener(column);
}
break;
case NotifyCollectionChangedAction.Remove:
foreach (var column in e.OldItems.OfType<DataGridColumn>())
{
RemoveListener(column);
}
break;
case NotifyCollectionChangedAction.Replace:
foreach (var column in e.NewItems.OfType<DataGridColumn>())
{
AddListener(column);
}
foreach (var column in e.OldItems.OfType<DataGridColumn>())
{
RemoveListener(column);
}
break;
}
}
protected override void OnDetaching()
{
base.OnDetaching();
foreach (var column in AssociatedObject.Columns)
{
RemoveListener(column);
}
}
private void AddListener(DataGridColumn column)
{
Descriptor.AddValueChanged(column, ResizeGrid);
}
private void RemoveListener(DataGridColumn column)
{
Descriptor.RemoveValueChanged(column, ResizeGrid);
}
private void ResizeGrid(object sender, EventArgs e)
{
var columnsWidth = AssociatedObject.Columns.Sum(c => c.ActualWidth);
AssociatedObject.MaxWidth = columnsWidth + 2;
AssociatedObject.InvalidateMeasure();
}
}
I still have some things to iron out about width coordination of two grids, but it looks to work for one.
there is seems to be a slight problem with both of your approaches. When I drag the left most column to the right, the whole grid is getting resized/ rolled inside (unfortunatly I don't have enough reputation to post the image).
So I have modified jjrdk ResizeGrid function, so it calculate the last column width and extends it all the way to the left. The grid HorizontalAlignment and HorizontalContentAlignment must be set to
HorizontalAlignment.Stretch.
void ResizeGrid(object sender, EventArgs e)
{
var scroll = ExTreeHelper.FindVisualChild<ScrollViewer>(AssociatedObject);
if (scroll != null && null != AssociatedObject.Columns && AssociatedObject.Columns.Count > 0)
{
var lastColumn = AssociatedObject.Columns.Last();
double dataGridWidth = AssociatedObject.Columns.Sum(c => c.ActualWidth) + 2.0;
if (scroll.ComputedHorizontalScrollBarVisibility != Visibility.Visible)
{
RemoveListener(lastColumn);
AssociatedObject.Columns.Last().Width =
AssociatedObject.Columns.Last().Width.DisplayValue + scroll.ViewportWidth - dataGridWidth;
AssociatedObject.Width = dataGridWidth + scroll.ViewportWidth - dataGridWidth;
AddListener(lastColumn);
}
else
{
AssociatedObject.HorizontalAlignment = HorizontalAlignment.Stretch;
AssociatedObject.HorizontalContentAlignment = HorizontalAlignment.Stretch;
AssociatedObject.Width = double.NaN;
}
} }
The only issue I have, is that the scroll bar is always there, even if all the columns has been fit.
There is still another issue, when all the columns are collapsed to the left, it starts flickering.
Is there anything that can be done, to really get rid of this white space?
Leon

Get width of ComboBoxItem's

I've got combobox binded to string[].
I haven't got clear combobox items. But I want measure my dropown items.
How can I get width of items in combobox at runtime. I need this to manage width of my combo.
If you want to do this and you're not sure if all your ComboBoxItems have been generated then you can use this code. It will expand the ComboBox in code behind and when all the ComboBoxItems within it are loaded, measure their size, and then close the ComboBox.
The IExpandCollapseProvider is in UIAutomationProvider
public void SetComboBoxWidthFromItems()
{
double comboBoxWidth = c_comboBox.DesiredSize.Width;
// Create the peer and provider to expand the c_comboBox in code behind.
ComboBoxAutomationPeer peer = new ComboBoxAutomationPeer(c_comboBox);
IExpandCollapseProvider provider = (IExpandCollapseProvider)peer.GetPattern(PatternInterface.ExpandCollapse);
EventHandler eventHandler = null;
eventHandler = new EventHandler(delegate
{
if (c_comboBox.IsDropDownOpen &&
c_comboBox.ItemContainerGenerator.Status == GeneratorStatus.ContainersGenerated)
{
double width = 0;
foreach (var item in c_comboBox.Items)
{
ComboBoxItem comboBoxItem = c_comboBox.ItemContainerGenerator.ContainerFromItem(item) as ComboBoxItem;
comboBoxItem.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
if (comboBoxItem.DesiredSize.Width > width)
{
width = comboBoxItem.DesiredSize.Width;
}
}
c_comboBox.Width = comboBoxWidth + width;
// Remove the event handler.
c_comboBox.ItemContainerGenerator.StatusChanged -= eventHandler;
c_comboBox.DropDownOpened -= eventHandler;
provider.Collapse();
}
});
// Anonymous delegate as event handler for ItemContainerGenerator.StatusChanged.
c_comboBox.ItemContainerGenerator.StatusChanged += eventHandler;
c_comboBox.DropDownOpened += eventHandler;
// Expand the c_comboBox to generate all its ComboBoxItem's.
provider.Expand();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
SetComboBoxWidthFromItems();
}
Try this function:
foreach(var item in MyComboBox.Items){
double width = item.ActualWidth;
}

Drag and Drop between 2 list boxes

Trying to implement drag and drop between 2 listboxes and all examples I've seen so far don't really smell good.
Can someone point me to or show me a good implementation?
Here's a sample form. Get started with a new WF project and drop two list boxes on the form. Make the code look like this:
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
listBox1.Items.AddRange(new object[] { "one", "two", "three" });
listBox1.MouseDown += new MouseEventHandler(listBox1_MouseDown);
listBox1.MouseMove += new MouseEventHandler(listBox1_MouseMove);
listBox2.AllowDrop = true;
listBox2.DragEnter += new DragEventHandler(listBox2_DragEnter);
listBox2.DragDrop += new DragEventHandler(listBox2_DragDrop);
}
private Point mDownPos;
void listBox1_MouseDown(object sender, MouseEventArgs e) {
mDownPos = e.Location;
}
void listBox1_MouseMove(object sender, MouseEventArgs e) {
if (e.Button != MouseButtons.Left) return;
int index = listBox1.IndexFromPoint(e.Location);
if (index < 0) return;
if (Math.Abs(e.X - mDownPos.X) >= SystemInformation.DragSize.Width ||
Math.Abs(e.Y - mDownPos.Y) >= SystemInformation.DragSize.Height)
DoDragDrop(new DragObject(listBox1, listBox1.Items[index]), DragDropEffects.Move);
}
void listBox2_DragEnter(object sender, DragEventArgs e) {
DragObject obj = e.Data.GetData(typeof(DragObject)) as DragObject;
if (obj != null && obj.source != listBox2) e.Effect = e.AllowedEffect;
}
void listBox2_DragDrop(object sender, DragEventArgs e) {
DragObject obj = e.Data.GetData(typeof(DragObject)) as DragObject;
listBox2.Items.Add(obj.item);
obj.source.Items.Remove(obj.item);
}
private class DragObject {
public ListBox source;
public object item;
public DragObject(ListBox box, object data) { source = box; item = data; }
}
}
the proper way to do a drag-drop control in .net is by running code in the 2nd control's DragDrop event handler.
It may "smell" weird, but this is how it works in .NET.
Google gave this: http://www.codeproject.com/KB/dotnet/csdragndrop01.aspx
It seems a pretty reasonable tutorial. If it smells bad, I think that's more to do with the API for drag and drop being awkward to use rather than the tutorial itself being poor.

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