We Keep Coding

How can I add in a template object into a C# Frame template

Here is code I have been working on with the help of Deczalof:
Here is the XAML code that I have
<t:PopupEntryFrame2 x:Name="newDeckNameEntry" TextChanged="newDeckNameEntry_TextChanged" />
With code behind:
public partial class CopyDeckPopup : Rg.Plugins.Popup.Pages.PopupPage
{
string originalName;
string originalDescription;
List<Deck> listDecks;
public CopyDeckPopup(string clickedDeckName, string clickedDeckDescription)
{
InitializeComponent();
listDecks = App.DB.GetAllDecks();
newDeckNameEntry.Text = clickedDeckName;
newDeckDescriptionEntry.Text = clickedDeckDescription;
originalName = clickedDeckName;
originalDescription = clickedDeckDescription;
OK_Button.IsEnabled = false;
}
private async void Cancel_Button_Clicked(object sender, EventArgs e)
{
await PopupNavigation.Instance.PopAsync(false);
}
private async void OK_Button_Clicked(object sender, EventArgs e)
{
if (IsBusy)
return;
IsBusy = true;
await PopupNavigation.Instance.PopAsync(false);
var newDeckNameEntryTextTrim = newDeckNameEntry.Text.Trim();
var newDeckDescriptionEntryTextTrim = newDeckDescriptionEntry.Text.Trim();
if (newDeckNameEntryTextTrim != originalName || newDeckDescriptionEntryTextTrim != originalDescription)
{
App.DB.CopyDeckToDb2(originalName, newDeckNameEntryTextTrim, newDeckDescriptionEntryTextTrim);
MessagingCenter.Send<PopupPage>(new PopupPage(), "PageRefresh");
}
IsBusy = false;
}
void newDeckNameEntry_TextChanged(object sender, EntryTextChangedEventArgs e)
{
NewDeckNameEntryValidator(e.NewTextValue);
}
void newDeckDescriptionEntry_TextChanged(object sender, EntryTextChangedEventArgs e)
{
var deckName = newDeckNameEntry.Text.Trim();
var isDeckAvailable = listDecks.Where(x => x.Name == deckName).SingleOrDefault();
if (isDeckAvailable == null)
{
OK_Button.IsEnabled = e.NewTextValue != originalDescription ? true : false;
}
}
void NewDeckNameEntryValidator(string newDeckNameEntry)
{
var newDeckNameEntryTrimmed = newDeckNameEntry.Trim();
var isDeckNameAvailable = listDecks.Where(x => x.Name == newDeckNameEntryTrimmed).SingleOrDefault();
if (string.IsNullOrWhiteSpace(newDeckNameEntryTrimmed) ||
isDeckNameAvailable != null ||
newDeckNameEntryTrimmed.StartsWith("::") ||
newDeckNameEntryTrimmed.EndsWith("::") ||
newDeckNameEntryTrimmed.Count(c => c == ':') > 2)
{
OK_Button.IsEnabled = false;
return;
}
OK_Button.IsEnabled = true;
}
}
and the C# code for a template:
public class PopupEntryFrame2 : CustomFrame
{
CustomEntry entry { get; set; }
public PopupEntryFrame2()
{
entry = new CustomEntry();
entry.SetBinding(PopupEntryFrame2.TextProperty, new Binding("Text", source: this));
entry.TextChanged += (s, a) =>
{
OnTextChanged(new EntryTextChangedEventArgs(a.NewTextValue, a.OldTextValue));
};
Content = entry;
CornerRadius = 5;
HasShadow = false;
SetDynamicResource(BackgroundColorProperty, "EntryFrameBackgroundColor");
SetDynamicResource(BorderColorProperty, "EntryFrameBorderColor");
SetDynamicResource(CornerRadiusProperty, "EntryFrameCornerRadius");
SetDynamicResource(HeightRequestProperty, "PopupEntryFrameHeight");
SetDynamicResource(MarginProperty, "PopupEntryFrameMargin");
SetDynamicResource(PaddingProperty, "PopupEntryFramePadding");
}
public class EntryTextChangedEventArgs : EventArgs
{
public EntryTextChangedEventArgs(String newValue = null, String oldValue = null)
{
NewTextValue = newValue;
OldTextValue = oldValue;
}
public String NewTextValue { get; }
public String OldTextValue { get; }
}
public event EventHandler TextChanged;
protected virtual void OnTextChanged(EntryTextChangedEventArgs args)
{
TextChanged?.Invoke(this, args);
}
public static readonly BindableProperty TextProperty =
BindableProperty.Create(nameof(Text), typeof(string), typeof(PopupEntryFrame2), default(string));
public string Text { get => (string)GetValue(TextProperty); set => SetValue(TextProperty, value); }
}
The error I get when building is this:
CopyDeckPopup.xaml(22,63): XamlC error XFC0002: EventHandler "newDeckNameEntry_TextChanged"
with correct signature not found in type "DecksTab.Pages.DeckOptions.CopyDeckPopup"

To achieve your goal you can simply add the Entry on your PopupEntryFrame class and define an Event there that connects with the TextChanged event in the original Entry.
This is done as illustrated in the code below (which is based on yours!)
using Test.Renderers;
namespace Test.Templates
{
public class PopupEntryFrame : CustomFrame
{
Entry entry { get; set; }
public PopupEntryFrame()
{
entry = new Entry();
entry.TextChanged += (s, a) =>
{
OnTextChanged(new EntryTextChangedEventArgs());
};
Content = entry;
CornerRadius = 5;
HasShadow = false;
SetDynamicResource(BackgroundColorProperty, "EntryFrameBackgroundColor");
SetDynamicResource(BorderColorProperty, "EntryFrameBorderColor");
SetDynamicResource(CornerRadiusProperty, "EntryFrameCornerRadius");
SetDynamicResource(HeightRequestProperty, "PopupEntryFrameHeight");
SetDynamicResource(MarginProperty, "PopupEntryFrameMargin");
SetDynamicResource(PaddingProperty, "PopupEntryFramePadding");
}
public class EntryTextChangedEventArgs : EventArgs
{
// class members
}
public event EventHandler TextChanged;
protected virtual void OnTextChanged(EntryTextChangedEventArgs args)
{
TextChanged?.Invoke(this, args);
}
}
}
And that's it. By doing that you can now write code like
<t:PopupEntry x:Name="newDeckDescriptionEntry" TextChanged="newDeckDescriptionEntry_TextChanged">
Update
In the comments someone suggested using ContentView, so let's take a look at how the same result could be achieved using that approach.
Disclaimer
First of all, it is important to know that Frame inherits itself from ContentView (from which acctualy it inherits its Content property!). In fact, from the documentation we know that
[Xamarin.Forms.ContentProperty("Content")]
[Xamarin.Forms.RenderWith(typeof(Xamarin.Forms.Platform._FrameRenderer))]
public class Frame : Xamarin.Forms.ContentView, Xamarin.Forms.IBorderElement, Xamarin.Forms.IElementConfiguration<Xamarin.Forms.Frame>
which means that by creating a Class/Control that inherits from Frame means that we are already using the ContentView approach.
Create the ContentView
First of all we create a ContentView and set its content to a new PopupFrame() which itself contains an Entry, as follows
public class PopupEntry : ContentView
{
Entry entry { get; set; }
public PopupEntry()
{
entry = new Entry();
Content = new PopupFrame()
{
Content = entry
};
}
}
Add an Event
Next, as is required by the OP, we define an Event for our ContentView that will be triggered when the Text in the Entry changed. Following the Documentation, this can be achieved by adding the following piece of code:
public class EntryTextChangedEventArgs : EventArgs
{
// class members
}
public event EventHandler TextChanged;
protected virtual void OnTextChanged(EntryTextChangedEventArgs args)
{
TextChanged?.Invoke(this, args);
}
Now, we can "link" the original TextChanged event from the Entry control to the new Event of our ContentView, as follows:
entry.TextChanged += (s, a) =>
{
OnTextChanged(new EntryTextChangedEventArgs());
};
Then, our ContentView code will look like
public class PopupEntry : ContentView
{
Entry entry { get; set; }
public PopupEntry()
{
entry = new Entry();
entry.TextChanged += (s, a) =>
{
OnTextChanged(new EntryTextChangedEventArgs());
};
Content = new PopupFrame()
{
Content = entry
};
}
public class EntryTextChangedEventArgs : EventArgs
{
// class members
}
public event EventHandler TextChanged;
protected virtual void OnTextChanged(EntryTextChangedEventArgs args)
{
TextChanged?.Invoke(this, args);
}
}
Wrapping up
With this ContentView defined, we can now write code like
<t:PopupEntry x:Name="newDeckDescriptionEntry" TextChanged="newDeckDescriptionEntry_TextChanged"/>
And that's it! I hope this was useful.
Happy coding!
P.S.:
A little note about the Event declaration: Since EntryTextChangedEventArgs is a copy of the original TextChangedEventArgs we can define the EntryTextChangedEventArgs class like
public class EntryTextChangedEventArgs : EventArgs
{
public EntryTextChangedEventArgs(String newValue = null, String oldValue = null)
{
NewTextValue = newValue;
OldTextValue = oldValue;
}
public String NewTextValue { get; }
public String OldTextValue { get; }
}
and then when instantiating this class we just feed it directly with the values from TextChangedEventArgs, as follows
entry = new Entry();
entry.TextChanged += (s, a) =>
{
OnTextChanged(new EntryTextChangedEventArgs(a.NewTextValue, a.OldTextValue));
};

how do I make beautiful flipping images?

When I opened the game launcher, I noticed how the news was implemented there.
And I really liked this idea, so I decided to do it in my project, first of all I made a panel, stuffed a few images into it, and then actually made two buttons with which I plan to flip through the images. BUT how to do it smoothly? Here is where the problem is, I do not understand how to make a smooth flipping of
the image

I can't tell how the images are sliding, flipping, stretching or whatever, but I think WinForms with GDI+ isn't the best choice. I think WPF would be better. I would also recommend using a suitable library for those kind of image manipulations.
However, if you want it very(!) simple you could use this class:
public class SlideAnimation
{
public event EventHandler<AnimationEventArgs> AnimationFinished;
private readonly Control Control;
private readonly Timer Timer;
private float fromXPosition;
public SlideAnimation(Control ctrl)
{
Control = ctrl;
Timer = new Timer();
Timer.Interval = 10;
Timer.Tick += Timer_Tick;
Control.Paint += Control_Paint;
}
public float Speed { get; set; }
public Image From { get; set; }
public Image To { get; set; }
public AnimationDirection Direction { get; set; }
public bool IsRunning
{
get
{
return Timer.Enabled;
}
}
public void StartAnimation()
{
// maybe move those checks into the setter of the corresponding property
if (this.From == null)
throw new InvalidOperationException();
if (this.To == null)
throw new InvalidOperationException();
if (this.Speed <= 0)
throw new InvalidOperationException();
fromXPosition = 0;
Timer.Enabled = true;
}
protected void OnAnimationFinished(AnimationEventArgs e)
{
AnimationFinished?.Invoke(this, e);
}
private void Timer_Tick(object sender, EventArgs e)
{
// increase or decrease the position of the first image
fromXPosition = fromXPosition + (this.Speed * this.Direction);
Control.Invalidate();
if (Math.Abs(fromXPosition) >= this.From.Width)
{
Timer.Enabled = false;
OnAnimationFinished(new AnimationEventArgs(this.Direction));
}
}
private void Control_Paint(object sender, PaintEventArgs e)
{
if (!Timer.Enabled)
return;
// draw both images next to each other depending on the direction
e.Graphics.DrawImage(this.From, new PointF(fromXPosition, 0));
e.Graphics.DrawImage(this.To, new PointF(fromXPosition - (this.From.Width * this.Direction), 0));
}
}
public enum AnimationDirection
{
Forward = -1,
Backward = 1
}
public class AnimationEventArgs : EventArgs
{
public AnimationEventArgs(AnimationDirection direction)
{
Direction = direction;
}
public AnimationDirection Direction { get; }
}
This class will only draw the images while the animation is active. Every other invalidation will not trigger the Control_Paint method.
Use following code for your Form:
public class Form1
{
private List<Image> imgList = new List<Image>();
private int currentIndex = 0;
private SlideAnimation animation;
public Slideshow()
{
InitializeComponent();
imgList.Add(Image.FromFile("pic1.bmp"));
imgList.Add(Image.FromFile("pic2.bmp"));
imgList.Add(Image.FromFile("pic3.bmp"));
imgList.Add(Image.FromFile("pic4.bmp"));
imgList.Add(Image.FromFile("pic5.bmp"));
animation = new SlideAnimation(this.Panel1);
animation.Speed = 20;
animation.AnimationFinished += AnimationFinished;
}
private void btnPrev_Click(object sender, EventArgs e)
{
if (currentIndex == 0)
return;
if (animation.IsRunning)
return;
animation.Direction = AnimationDirection.Backward;
animation.From = imgList[currentIndex];
animation.To = imgList[currentIndex - 1];
animation.StartAnimation();
}
private void btnNext_Click(object sender, EventArgs e)
{
if (currentIndex == imgList.Count - 1)
return;
if (animation.IsRunning)
return;
animation.Direction = AnimationDirection.Forward;
animation.From = imgList[currentIndex];
animation.To = imgList[currentIndex + 1];
animation.StartAnimation();
}
private void AnimationFinished(object sender, AnimationEventArgs e)
{
currentIndex = currentIndex - (1 * e.Direction);
}
private void Panel1_Paint(object sender, PaintEventArgs e)
{
e.Graphics.DrawImage(imgList[currentIndex], 0, 0);
}
}
Since there are a lot of drawing operations you may use a panel which supports DoubleBuffer.
public class DoubleBufferedPanel : Panel
{
public DoubleBufferedPanel()
{
SetStyle(ControlStyles.OptimizedDoubleBuffer | ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint, true);
}
}
Keep in mind that this example is very simple and far from "fancy".

USer Control Custom event and set get property

I have 2 labels and a property in user control:
Here is property:
private int _SelectIndex;
[Browsable(true)]
public int SelectIndex { get; set; }
and 2 labels:
Label lbl1, lbl2;
void iControl()
{
lbl1 = new Label();
lbl2 = new Label();
lbl1.Name = "lbl1";
lbl2.Name = "lbl2";
lbl1.Click += lbl_Click;
lbl2.Click += lbl_Click;
this.Controls.Add(lbl1);
this.Controls.Add(lbl2);
}
Click:
void lbl_Click(object sender, EventArgs e)
{
Label selectedlbl = sender as Label;
if(selectedlbl.Name == "lbl1")
this.Select = 1;
else
this.Select = 2;
}
Class Event:
public class SelectEventArgs : EventArgs
{
private int index;
public SelectEventArgs(int index)
{
this.index = index;
}
public int ItemIndex
{
get
{
return index;
}
}
}
Custom event in my control:
public event EventHandler SelectEvent;
protected virtual void OnSelectEvent()
{
if (SelectEvent!= null)
SelectEvent(this, new SelectEventArgs(this._SelectIndex));
}
I need an event to get and set property value in MainForm as following:
int index = 0;
public Form1()
{
InitializeComponent();
this.icontrol = new iControl();
this.SelectEvent += Select();
}
void Select(object sender, SelectItem e)
{
//use this to set value of Select
this.icontrol.SelectIndex = index;
//and this to get value of Select
index = this.icontrol.SelectIndex;
}
Select is empty.
How to get it to work?

I post here for any one need it:
1.Declare a delegate:
public delegate void SelectIndexEventHandler(object sender, SelectEventArgs e);
public class SelectEventArgs : EventArgs
{
private int index;
public SelectEventArgs(int index)
{
this.index = index;
}
public int ItemIndex
{
get { return index; }
set { index = value; }
}
}
2. declare an event SelectIndexChanged and a method OnSelectIndexChanged:
public event SelectIndexEventHandler SelectIndexChanged;
protected virtual void OnSelectIndexChanged(SelectEventArgs e)
{
if (SelectIndexChanged != null)
SelectIndexChanged(this, e);
}
3.Call it in setter:
public int SelectIndex
{
get { return _SelectIndex; }
set {
_SelectIndex = value;
OnSelectIndexChanged(new SelectEventArgs(value));
}
}
and then MainForm:
this.gListBox1.SelectIndexChanged += icontrol_SelectIndexChanged;
void icontrol_SelectIndexChanged(object sender, SelectEventArgs e)
{
var current = e.ItemIndex;
}
thank again jbmintjb Reza Aghaei.

The code has multiple issues. Consider these tips to solve the issues:
SelecetEvent does't belong to the Form. The event belongs to icontrol.
this.SelectEvent += Select(); is incorrect, you should use:
icontrol.SelectEvent += Select;
When you have a custom event args, you should define the event this way:
public event EventHandler<SelectEventArgs> SelectEvent;
You should raise the event in setter of your property, using OnSelectEvent method which you created.
To learn more about events take a look at C# Handling and Raising Events.

Take a look at the SelectedIndexChanged event on the listbox control, think that is what you are looking for

Is Threading Communication Needed Here?

I'm trying to get this code to add something to the screen once a particular time of day is reached. It's rigged to an event. The code works on a single-threaded program, but not with threading, which is what I need. The data is added, as needed, but doesn't show to the screen like it did on the single-thread execution (timeStack is a StackPanel, TimeEntry is a UserControl).
Code:
Mainwindow.xaml.cs:
public partial class MainWindow : Window
{
public MainWindow()
{
SM = new SessionManager();
SM.NewDayEvent += SplitSession;
InitializeComponent();
//Code removed for clarity
}
private void SplitSession(object sender, EventArgs ea)
{
SM.SplitSession();
string s =((TimeEntry)SM.Entries.Last(x=>x.GetType()==typeof(TimeEntry))).Data.Comment;
AddSessionStamp();
entryAdder_Click(null, null);
((TimeEntry)SM.Entries.Last(x => x.GetType() == typeof(TimeEntry))).Data.Comment = s;
this.Focus();
}
private void AddSessionStamp()
{
TextBlock timeStamp = new TextBlock();
timeStamp.Text = "-----------" + SM.CurrentSession.Name + "-----------";
timeStack.Children.Add(timeStamp);
}
private void entryAdder_Click(object sender, RoutedEventArgs e)
{
//Subscribe to the assorted events
TimeEntry newTE = SM.addNewTimeEntry();
//Subscribe to the assorted events
RegisterToTimeEntry(newTE);
timeStack.Children.Add(newTE);
}
}
SessionManager.cs:
public class SessionManager : INotifyPropertyChanged
{
public delegate void NewDayEventHandler(object sender, EventArgs ea);
public event NewDayEventHandler NewDayEvent;
private Timer _timer;
private Stopwatch _clockWatch;
private DateTime current_time;
#region Properties
public DateTime CurrentTime
{
get
{
return DateTime.Now;
}
set
{
if (current_time != value)
{
current_time = value;
OnPropertyChanged("CurrentTime");
}
}
}
public List<Session> OpenSessions { get; private set; }
public ObservableCollection<UIElement> Entries { get; private set; }
public Session CurrentSession
{
get
{
return current_session;
}
set
{
if (current_session != value)
{
current_session = value;
OnPropertyChanged("CurrentSession");
}
}
}
#endregion
public SessionManager()
{
_clockWatch = new Stopwatch();
_timer = new Timer(1000);//one second
_timer.Elapsed += timerElapsed;
//Code removed for clarity
current_time = new DateTime();
CurrentTime = DateTime.Now;
_timer.Start();
}
#region Methods
#region Event Methods
/// <summary>
/// Registered to Timer.Elapsed Event
/// (See constructor)
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
public void timerElapsed(object sender, ElapsedEventArgs e)
{
CurrentTime = DateTime.Now;
if ((CurrentTime.TimeOfDay.Hours == 13 &&
CurrentTime.TimeOfDay.Minutes == 23 &&
CurrentTime.TimeOfDay.Seconds == 0) &&
NewDayEvent != null)
{
NewDayEvent(this, new EventArgs());
}
}
#endregion
#region Class Methods
private void OnPropertyChanged([CallerMemberName] string member_name = "")
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(member_name));
}
}
#endregion
#endregion
public void SplitSession()
{
Session prevSesh = CurrentSession;
OpenSessions.Add(new Session());
CurrentSession = OpenSessions.Last();
current_session.addComment(
((TimeEntry)Entries.Last(
x => x.GetType() == typeof(TimeEntry))
).Data.Comment);
}
}

Event handler functions are executed in the same Thread as the one who raised the event. Problem is you can't update the UI from another thread that the Dispatcher thread. You'll need to execute the callback function (or at least the update part) inside a Dispatcher Invoke or BeginInvoke:
Application.Current.Dispatcher.Invoke(new Action(() => {
//your UI update
}));

Capture user click and typing in a custom WPF TextBox-like control?

Trying to make an equation editor like that in Microsoft Word in C# and WPF. XML cannot be used; it has to be purely programmatic.
Right now I have LineGUIObject : System.Windows.Controls.WrapPanel, which is like System.Windows.Controls.TextBox, except that instead of just showing strings it shows each element of a List<System.Windows.UIElement> in order.
Now I want for a user to be able to click on an instance of LineGUIObject and type into it. The holdup is that I don't know how to capture the user's click or read the input that they type. How can this be done?
Note: This question is not asking how to handle input once captured; just how to get the input in the first place. For example, is there some event that fires off after the user clicks it or something? I can't seem to find one for System.Windows.Controls.WrapPanel, which might imply that I need to use another type of object, or..?
Current code:
public class LineGUIObject
: System.Windows.Controls.WrapPanel
{
private List<System.Windows.UIElement> _uiElementList;
private CursorGUIObject _cursor;
private int? _cursorIndex;
public LineGUIObject(System.Windows.Threading.Dispatcher dispatcher)
: base()
{
this.UIElementList = new List<System.Windows.UIElement>();
this.Cursor = new CursorGUIObject(dispatcher, 25, 1.5, 250);
this.UIElementList.Add(this.Cursor);
this.AddText("[junk string just to see this otherwise invisible object while debugging]");
}
protected void InterpretUserKeyStroke(/* ??? */)
{
//How do we get this method to be called on user input,
//e.g. when the user types "1"?
throw new NotImplementedException();
}
protected void AddText(string text)
{
this.UIElementList.Add(new System.Windows.Controls.TextBlock(new System.Windows.Documents.Run(text)));
this.UpdateDisplay();
}
protected List<System.Windows.UIElement> UIElementList { get { return this._uiElementList; } private set { this._uiElementList = value; } }
protected CursorGUIObject Cursor { get { return this._cursor; } private set { this._cursor = value; } }
protected int? CursorIndex
{
get { return this._cursorIndex; }
set
{
int? nullablePriorIndex = this.CursorIndex;
if (nullablePriorIndex != null)
{
int priorIndex = nullablePriorIndex.Value;
this.UIElementList.RemoveAt(priorIndex);
}
if (value == null)
{
this._cursorIndex = null;
}
else
{
int newIndex = value.Value;
if (newIndex < 0)
{
newIndex = 0;
}
else
{
int thisListCount = this.UIElementList.Count;
if (newIndex > thisListCount) { newIndex = thisListCount; }
}
this.UIElementList.Insert(newIndex, this.Cursor);
this._cursorIndex = newIndex;
}
this.UpdateDisplay();
}
}
protected void UpdateDisplay()
{
this.Children.Clear();
foreach (System.Windows.UIElement uiElement in this.UIElementList) { this.Children.Add(uiElement); }
}
}
public class CursorGUIObject
: System.Windows.Controls.WrapPanel
{
public const double MINIMUM_BLINK_TIME_IN_MS = 5;
public const double MINIMUM_HEIGHT = 0.5;
public const double MINIMUM_WIDTH = 0.5;
private object ToggleVisibilityLock = new object();
private delegate void TimerIntervalDelegate();
private System.Windows.Shapes.Rectangle _rectangle;
private System.Timers.Timer _timer;
private System.Windows.Threading.Dispatcher _dispatcher;
public CursorGUIObject(System.Windows.Threading.Dispatcher dispatcher, double height, double width, double blinkTimeInMS)
{
this.Dispatcher = dispatcher;
System.Windows.Shapes.Rectangle rectangle = new System.Windows.Shapes.Rectangle();
rectangle.Width = width > MINIMUM_WIDTH ? width : MINIMUM_WIDTH;
rectangle.Height = height > MINIMUM_HEIGHT ? height : MINIMUM_HEIGHT;
rectangle.Fill = System.Windows.Media.Brushes.Black;
this.Rectangle = rectangle;
this.Children.Add(rectangle);
System.Timers.Timer timer = new System.Timers.Timer(blinkTimeInMS > MINIMUM_BLINK_TIME_IN_MS ? blinkTimeInMS : MINIMUM_BLINK_TIME_IN_MS);
this.Timer = timer;
timer.Elapsed += timer_Elapsed;
timer.Start();
}
~CursorGUIObject()
{
System.Timers.Timer timer = this.Timer;
if (timer != null) { timer.Dispose(); }
}
private void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
Delegate timerDelegate = new TimerIntervalDelegate(ToggleVisibility);
this.Dispatcher.BeginInvoke(timerDelegate);
}
protected void ToggleVisibility()
{
lock (ToggleVisibilityLock)
{
if (this.Rectangle.Visibility.Equals(System.Windows.Visibility.Hidden))
{
this.Rectangle.Visibility = System.Windows.Visibility.Visible;
}
else
{
this.Rectangle.Visibility = System.Windows.Visibility.Hidden;
}
}
}
protected System.Windows.Shapes.Rectangle Rectangle { get { return this._rectangle; } private set { this._rectangle = value; } }
protected System.Timers.Timer Timer { get { return this._timer; } private set { this._timer = value; } }
protected System.Windows.Threading.Dispatcher Dispatcher { get { return this._dispatcher; } private set { this._dispatcher = value; } }
}

Pretty much all WPF controls provide access to the UIElement.PreviewMouseDown Event, which you can use to monitor mouse clicks. So, this event lets you monitor when each object is clicked on. Next, I'd advise you to use a small Popup control to popup a TextBox that the user could enter a value with:
<Popup Name="Popup">
<Border BorderBrush="Black" BorderThickness="1" CornerRadius="5" Padding="5">
<TextBox Text="{Binding InputText}" />
</Border>
</Popup>
Depending on how you have set up your project, you could open the Popup from the event handler:
private void YourObject_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
Popup.IsOpen = true;
}

Turns out that LineGUIObject just needed to have this.Focusable = true; set in its constructor so that it could receive the keyboard's focus when clicked.
Now that it can be focused on, this.KeyUp += LineGUIObject_KeyUp; also in the constructor, and
protected override void OnKeyDown(System.Windows.Input.KeyEventArgs e)
{
this.AddText(e.Key.ToString());
}
Even this had a problem at first since my LineGUIObject was nested in a ScrollViewer which kept stealing focus immediately after the LineGUIObject would receive it. This was fixed by making the ScrollViewer to be unable to get focus, i.e. <ScrollViewer VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto" Focusable="False"/>.