change main form controls by trigger event inside canvas - wpf

Question

I am currently working on a project that required me to use a canvas in order to draw rectangles around specific places in a picture (to mark places)
Each rectangle (actually "rectangle" since it is also a custom class that I created by inheriting from the Grid class and contain a rectangle object) contains properties and data about the marked place inside the picture.
my main form contains controls such as TextBox ,DropDownLists and etc.
Now what I am trying to do is that for each time I am clicking on the "rectangle" object the main form controls will be filled with the object data.
I do not have access to those controls from the canvas class.
this code is inside the costume canvas class to add the object into the canvas:
protected override void OnMouseLeftButtonDown( MouseButtonEventArgs e)
{
if(e.ClickCount==2)
{
testTi = new TiTest();
base.OnMouseLeftButtonDown(e);
startPoint = e.GetPosition(this);
testTi.MouseLeftButtonDown += testTi_MouseLeftButtonDown;
Canvas.SetLeft(testTi, e.GetPosition(this).X);
Canvas.SetTop(testTi, e.GetPosition(this).X);
this.Children.Add(testTi);
}
}
and by clicking an object that is placed inside the canvas i want to get the information.
for now just want to make sure i am getting the right object with a simple messagebox
void testTi_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
MessageBox.Show(sender.GetType().ToString());
}
this is my costume "Rectangle" class
class TiTest:Grid
{
private Label tiNameLabel;
private Rectangle tiRectangle;
private String SomeText = string.Empty;
private String version = "1.0";
private String application = "CRM";
private String CRID = "NNN";
public String SomeText1
{
get { return SomeText; }
set { SomeText = value; }
}
public Rectangle TiRectangle
{
get { return tiRectangle; }
set { tiRectangle = value; }
}
public Label TiNameLabel
{
get { return tiNameLabel; }
set { tiNameLabel = value; }
}
public TiTest()
{
this.SomeText = "Hello World!!";
this.TiNameLabel = new Label
{
Content = "Test Item",
VerticalAlignment = System.Windows.VerticalAlignment.Top,
HorizontalAlignment = System.Windows.HorizontalAlignment.Left
};
TiRectangle = new Rectangle
{
Stroke = Brushes.Red,
StrokeDashArray = new DoubleCollection() { 3 },//Brushes.LightBlue,
StrokeThickness = 2,
Cursor = Cursors.Hand,
Fill = new SolidColorBrush(Color.FromArgb(0, 0, 111, 0))
};
Background= Brushes.Aqua;
Opacity = 0.5;
this.Children.Add(this.tiNameLabel);
this.Children.Add(this.tiRectangle);
}
}
is there any way to access the main form controls from the costume canvas class or by the costume rectangle class?
Thanks in advance

Answer 1

You can have your main window be binded to a singletone ViewModel holding the properties of the rectangles.
ViewModel
public class MainWindowViewModel : INotifyPropertyChanged
{
#region Singletone
private static MainWindowViewModel _instance;
private MainWindowViewModel()
{
}
public static MainWindowViewModel Instance
{
get
{
if (_instance == null)
_instance = new MainWindowViewModel();
return _instance;
}
}
#endregion
#region Properties
private string _someInfo;
public string SomeInfo
{
get
{
return _someInfo;
}
set
{
if (_someInfo != value)
{
_someInfo = value;
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs("SomeInfo"));
}
}
}
#endregion
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
#endregion
}
In main window xaml
<TextBox Text="{Binding SomeInfo}"/>
Also set the view model as your main window data context (in main window constructor for exmaple)
this.DataContext = MainWindowViewModel.Instance;
Finally, from where you handle the click event of the rectangles (testTi_MouseLeftButtonDown), access the MainWindowViewModel instance and set it's properties accordingly.
MainWindowViewModel.Instance.SomeInfo = myRectangle.SomeInfo;
This will trigger the PropertyChanged event, which will update your control's on the main window.
If you are not familiar with the MVVM (Model, View. View Model) pattern you can read about it here
Hope this helps