Develop Reference

How to find first editable control to focus on in a page

My current function only finds first Textbox which is not totally correct. Control class doesn't have IsEditable property.
private static Control FindFocusableControl(Control CurrentControl)
{
if (CurrentControl.Visible)
{
if (CurrentControl is TextBox)
{
return CurrentControl;
}
if (CurrentControl.HasControls())
{
foreach (Control CurrentChildControl in CurrentControl.Controls)
{
Control focusableControl = FindFocusableControl(CurrentChildControl);
if (focusableControl != null)
{
return focusableControl;
}
}
}
}
return null;
}

On the first recursion for the first child control, the child control is probably not visible so the routine exits.
if (CurrentControl.Visible)
You might need a different kind of check at this point, perhaps check for textbox first, then if visible.

Silverlight RadComboBox make whole texbox area clickable

Is it possible to make the whole text area of the RadComboBox clickable while having IsEditable=true and ReadOnly=True?
I would just set IsEditable = false but unfortunately I need it to be editable in order to display custom text when something is selected (I have it set so multiple things can be selected and present a list of the selected items). If I disable IsEditable then I lose the .Text attribute and can't set a custom text.
My two best bets would be:
1) somehow apply a style that makes the whole textbar clickable and not just the arrow
2) somehow apply custom text display when IsEditable is set to false.
Unfortunately I don't know how to do either so any help would be nice. Thanks
Edit: This would be ideal, except that we're using Silverlight and not ASP.net
http://demos.telerik.com/aspnet-ajax/combobox/examples/functionality/checkboxes/defaultcs.aspx
This is probably more realistic, just to somehow make the text area clickable so it opens the dropdown menu. Just like the ComboBox on the right, minus being able to type. http://demos.telerik.com/aspnet-ajax/combobox/examples/functionality/comboboxvsdropdownlist/defaultcs.aspx

I can think of several solutions, of varying elegance. Here is one that might be suitable to close your remaining gap between the Arrow-ToggleButton and the Text-Input-Area. And now that I think about it... maybe you can get rid of that rather smelly and fragile side-effect-piggybacking with the OpenDropDownOnFocus property (which will break as soon as a click does not change the focus owner).
Register a MouseLeftButtonDown click handler with the RadComboBox, you can choose to get all events, not only unhandled events. Then we can toggle the DropDown from there. But we don't want to interfere with the Arrow-ToggleButton, therefore we check from where the mouse click originated.
public class MyView : UserControl
{
public MyView()
{
InitializeComponent();
MouseButtonEventHandler handler = OnComboBoxClicked;
radComboBox.AddHandler( UIElement.MouseLeftButtonDownEvent, handler,
handledEventsToo: true );
}
private void OnComboBoxClicked( object sender, MouseButtonEventArgs args )
{
if (!args.Handled ||
!args.IsRoutedEventFromToggleButton(
togglebuttonAncestorToStopTheSearch: (UIElement) sender))
{
ToggleDropDown();
}
}
}
and extension methods for easier use:
public static class ControlExtensions
{
public static bool IsRoutedEventFromToggleButton(
this RoutedEventArgs args,
UIElement togglebuttonAncestorToStopTheSearch )
{
ToggleButton toggleButton = ((UIElement) args.OriginalSource)
.GetAncestor<ToggleButton>( togglebuttonAncestorToStopTheSearch );
return toggleButton != null;
}
public static TAncestor GetAncestor<TAncestor>(
this DependencyObject subElement,
UIElement potentialAncestorToStopTheSearch )
where TAncestor : DependencyObject
{
DependencyObject parent;
for (DependencyObject subControl = subElement; subControl != null;
subControl = parent)
{
if (subControl is TAncestor) return (TAncestor) subControl;
if (object.ReferenceEquals( subControl,
potentialAncestorToStopTheSearch )) return null;
parent = VisualTreeHelper.GetParent( subControl );
if (parent == null)
{
FrameworkElement element = subControl as FrameworkElement;
if (element != null)
{
parent = element.Parent;
}
}
}
return null;
}
}

I ended up finding a multiselectcombobox that someone else implemented here:
http://www.telerik.com/support/code-library/a-multiselect-combobox
I didn't need the whole combobox itself since we already had one implemented so I just looked at how the person was displaying a custom message while the combo box IsEditable was set to false.
After looking at that code for a while and seeing how I can make it work for me, I put
<ucControls:RadComboBox.SelectionBoxTemplate>
<DataTemplate>
<TextBlock Text="{Binding Text,ElementName=RadCombo}" />
</DataTemplate>
</ucControls:RadComboBox.SelectionBoxTemplate>
inside the XAML of our own custom MultiSelectComboBox. (RadCombo being the name of the particular control that I wanted the Text to be linked to)
<ucControls:RadComboBox
x:Name="RadCombo"
Text=""
........
<ucControls:RadComboBox.SelectionBoxTemplate>
<DataTemplate>
<TextBlock Text="{Binding Text,ElementName=RadCombo}" />
</DataTemplate>
</ucControls:RadComboBox.SelectionBoxTemplate>
.......
</ucControls:RadComboBox>
Using the built in SelectionBoxTemplate, this basically just added a TextBlock overlay, and the content was bound to the RadComboBox's own Text, so when we would set the Text of the RadComboBox, the TextBlock would update itself.
This was the most effective way for us to do it because it required minimal code changes, and no structure changes since we already had all the code in place for checking boxes and setting a custom text.
Hope this helps someone, best of luck!

How to use ctrl key + mouse click to select multiple controls?

Probably this question has already an answer here but I was not able to find it..
I have a tabControl with a flowlayoutpanel in each tab page where I can add controls at run time. I can rearrange them, move them across tab pages.. How can I select multiple controls to be able to move them around using ctrl key + mouse click?
This is my drag event so far:
private void control_DragDrop(object sender, DragEventArgs e)
{
Control target = new Control();
target.Parent = sender as Control;
if (target != null)
{
int targetIndex = FindCSTIndex(target.Parent);
if (targetIndex != -1)
{
string cst_ctrl = typeof(CustomControl).FullName;
if (e.Data.GetDataPresent(cst_ctrl))
{
Button source = new Button();
source.Parent = e.Data.GetData(cst_ctrl) as CustomControl;
if (targetIndex != -1)
fl_panel = (FlowLayoutPanel)tabControl1.SelectedTab.Controls[0];
if (source.Parent.Parent.Name == target.Parent.Parent.Parent.Name)
{
this.fl_panel.Controls.SetChildIndex(source.Parent, targetIndex);
}
else
{
target.Parent.Parent.Parent.Controls.Add(source.Parent);
this.fl_panel.Controls.SetChildIndex(source.Parent, targetIndex);
}
}
}
}
}
private int FindCSTIndex(Control cst_ctr)
{
fl_panel = (FlowLayoutPanel)tabControl1.SelectedTab.Controls[0];
for (int i = 0; i < this.fl_panel.Controls.Count; i++)
{
CustomControl target = this.fl_panel.Controls[i] as CustomControl;
if (cst_ctr.Parent == target)
return i;
}
return -1;
}

This is not an easy, nor a common task. But surely doable and depending on preconditions could become trivial without need to spend multi-man-year effort on it ^^.
You have many options:
controls support selection;
container control support children controls selection;
overlay.
Handling selection is pretty easy: have a dictionary (or a control property, possibly using Tag) to store if control is selected or not, show selection somehow, when control is Ctrl-clicked invert selection. You can even provide Shift-key selection.
As #Hans Passant commented, you can use overlay window (invisible window on top of everything) to draw selection reticle there as well as handle selection and dragging itself. Or it could be a custom control with property IsSelected, setting which will draw something (border?) to indicate selection.
Easiest option would be to create SelectionPanel control, which can host any other controls inside, has IsSelected indication and is draggable. When children is added subscribe to MouseUp/MouseDown events or you can only allow to drag if special area of SelectionPanel is clicked. To example, you could have option Enable dragging in your software, when set all SelectionPanels will display special area (header?) which you can drag or Ctrl-click.

How does one get a ListView (GridView) cell's contents when clicked with a mouse

I am trying to get the text value of a "cell" inside of a GridView that is set as the view of a ListView. I do not want to get the SelectedItem of the ListView as that just returns my entire View Model (but not which property the cell refers to).
I am able to get the text value by responding to direct mouse events (up down or whatever) and if the value is a textblock, obviously I can use the text. This works great and as of right now this is my only solution, although its currently limited.
I would like to take it a step further and be able to click anywhere with in the cell area, navigate around to find the appropriate textblock and then use that value. I have tried a half million ways to do this but what seems logical doesn't seem to quite work out like it should.
Setup:
I have a dynamic GridView that creates its own columns and bindings based on data models that I pass to it. I am using a programmatic cell template (shown below) to have individual control over the cells, particularly so I can add a "border" to it making it actually separate out each cell. I have named the objects so I can access them easier when I'm navigating around the VisualTree.
Here is the Template Code. (Note that the content presenter originally was a textblock itself, but this was changed for later flexibility)
private DataTemplate GetCellTemplate(string bindingName)
{
StringBuilder builder = new StringBuilder();
builder.Append("<DataTemplate ");
builder.Append("xmlns='http://schemas.microsoft.com/winfx/");
builder.Append("2006/xaml/presentation' ");
builder.Append("xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml' ");
builder.Append("xmlns:local = 'clr-namespace:XXXXXXXX");
builder.Append(";assembly=XXXXXXXXX'>");
builder.Append("<Border Name=\"border\" BorderThickness=\"1,0,0,0\" BorderBrush=\"Gray\" Margin=\"-6,-3,-6,-3\">");
builder.Append("<Grid Margin=\"6,3,6,3\">");
builder.Append("<ContentPresenter Name=\"content\" HorizontalAlignment=\"Stretch\" Content=\"{Binding ");
builder.Append(string.Format("{0}", bindingName));
builder.Append("}\"/>");
builder.Append("</Grid>");
builder.Append("</Border>");
builder.Append("</DataTemplate>");
DataTemplate cellTemplate= (DataTemplate)XamlReader.Parse(builder.ToString());
return cellTemplate;
}
What I have Tried:
The logical approach for me was to react to a Mouse event. From the object that had the mouse event I would do either
A. Look at its children to find a textblock, or
B. Get its parent then look for child with a textblock.
My assumption is that if I click in white space I'm clicking in a container that has my textblock. So far the two things that come up are a Border and a Rectangle (if I don't click the text itself). A. Returns absolutely nothing except for the recangle and the border. When I do B i can find textblocks but they are every single text block in the entire row.
So what I try to do from that is get all textblocks, then go backwards till I find which one has a IsMouseOver property as true. It turns out none of these objects EVER have a IsMouseOver except the content presenter for the entire row. So this seems to indicate to me is that the whitespace in the cells does not actually contain the textblock.
What I find is that when I click on the Border and start looking at children, I eventually get to a container that has a rectangle (the rectangle I click) and a grid row view presenter. The presenter shows all of the objects inside the row (hence why i would get all textblocks when i do this recursive scan).
Here is some of the code used to do this to get an idea of what i'm doing. I have written about 10 different versions of this same recursive code generally attempting to find who has the Mouse over it and is related to a textbox.
private void OnPreviewMouseUp(object sender, MouseButtonEventArgs e)
{
object original = e.OriginalSource;
if (original is TextBlock)
{
this.valueTextBlock.Text = ((TextBlock)original).Text;
}
else if (original is FrameworkElement)
{
var result = GetAllNestedChildren<Border>(VisualTreeHelper.GetParent((DependencyObject)original)).Where(x => x.Name == "border").Where(x => HasAChildWithMouse(x)).ToList();
}
else
{
this.valueTextBlock.Text = string.Empty;
}
}
private bool HasAChildWithMouse(UIElement element)
{
if (element.IsMouseOver || element.IsMouseDirectlyOver)
return true;
var childCount = VisualTreeHelper.GetChildrenCount(element);
for (int i = 0; i < childCount; ++i)
{
var child = VisualTreeHelper.GetChild(element, i);
if (child is UIElement)
if (HasAChildWithMouse((UIElement)child))
return true;
}
return false;
}
private IEnumerable<T> GetAllNestedChildren<T>(DependencyObject obj) where T : UIElement
{
if (obj is T)
yield return obj as T;
var childCount = VisualTreeHelper.GetChildrenCount(obj);
for (int i = 0; i < childCount; ++i)
{
var child = VisualTreeHelper.GetChild(obj, i);
foreach (var nested in GetAllNestedChildren<T>(child))
yield return nested;
}
}
private T GetObjectByTypeParentHasMouse<T>(DependencyObject obj) where T : UIElement
{
if (obj is T)
{
if ((VisualTreeHelper.GetParent(obj) as UIElement).IsMouseOver )
{
return obj as T;
}
}
var childCount = VisualTreeHelper.GetChildrenCount(obj);
for (int i = 0; i < childCount; ++i)
{
var child = VisualTreeHelper.GetChild(obj, i);
var correctType = GetObjectByTypeParentHasMouse<T>(child);
if (correctType != null)
return correctType;
}
return null;
}
private T GetContainedType<T>(DependencyObject obj, bool checkForMouseOver) where T : UIElement
{
if (obj is T && ((T)obj).IsMouseOver)
return obj as T;
var childCount = VisualTreeHelper.GetChildrenCount(obj);
for (int i = 0; i < childCount; ++i)
{
var child = VisualTreeHelper.GetChild(obj, i);
var correctType = GetContainedType<T>(child, checkForMouseOver);
if (correctType != null)
return correctType;
}
return null;
}
The other approach I took was to start with the TextBlock itself, find its containing parent and find out how i can navigate to the answer. I find the templateparent is the ContentPresenter (named ="content") I find the grid, and then the border. The parent of the border is a content presenter whos content is the data view model for the entire row. The parent of this contentpresenter is the grid column's presenter. This is the same one that i was navigating up to in the other one.
It would appear that the first approach objects while are contain the cell do not actually contain the textblock or the entire cell templated items. It would appear to me there is no way to go from the Border or Rectangle that is clicked, back to the actual text field.
"Long story short" is there ANY way to make this connection?
(Btw I am not willing to give up this ListView/GridView because its payoffs far outweigh this negative and I'd gladly give up on this idea to keep the rest).

I think you sjould be able to either
1) Add some kind of (toggle)button to the root of your data template, and either bind to Command and handle it on your viewmodel or bind to IsChecked/IsPressed and handle changes via data triggers or w/e on the view side.
2) Add EventTrigger to your datatemplate at some point, and handle PreviewNouseUp/Down events there via simple animations.

WPF TreeView Scrolled to Bottom automatically?

WPF default TreeView is scrolled to bottom of the node automatically where as we need to show the top view of the tree view. How to do that?
Also I could not get the scroll viewer by walking down the Visual Tree.

Preselect top node and call TreeViewItem.BringIntoView method on selection changed event. Call TreeView.ItemContainerGenerator.ContainerFromItem(e.NewValue) to get hold of the TreeViewItem.

This code is very rough.
The key to getting the TreeViewItem.BringIntoView() to get an item to the top, is to first scroll the TreeView to the bottom rather than the top.
To do this, we need to access the ScrollViewer inside the TreeView's control template first. Lots of messing around IMO, that should have been provided in the framework from the outset.
Your item control in this case, should be your TreeViewItem that you are trying to get to the top.
The uxTree control is the TreeView.
item.IsSelected = true;
ScrollViewer scroller = (ScrollViewer)this.FindVisualChildElement(this.uxTree, typeof(ScrollViewer));
scroller.ScrollToBottom();
item.BringIntoView();
private FrameworkElement FindVisualChildElement(DependencyObject element, Type childType)
{
int count = VisualTreeHelper.GetChildrenCount(element);
for (int i = 0; i < count; i++)
{
var dependencyObject = VisualTreeHelper.GetChild(element, i);
var fe = (FrameworkElement)dependencyObject;
if (fe.GetType() == childType)
{
return fe;
}
FrameworkElement ret = null;
if (fe.GetType().Equals(typeof(ScrollViewer)))
{
ret = FindVisualChildElement((fe as ScrollViewer).Content as FrameworkElement, childType);
}
else
{
ret = FindVisualChildElement(fe, childType);
}
if (ret != null)
{
return ret;
}
}
return null;
}