dotnet thoughts

WPF Menu - How to implement Shortcut Heys

There are many ways to add shortcut keys in WPF

# Using Underscore - In the Header Property, put the "_" before the Text, and you can use "ALT+<Key>". This is not Shortcut key, it is normally called "HotKey"

   1:  <MenuItem Header="_Open" /> 

# Using InputGestureText - This is the way Visual Studio gives directly. - You can set a Key combination directly over here. 

   1:  <MenuItem Header="_Open" InputGestureText="Ctrl + O" /> 

But it will invoke the click event, even if we use the Key combination. This is for display purpose only.

#Using CommandBindings - - I found this way is better and easier one

1. In the markup create the command Bindings using Command Collections.
   

   <CommandBinding Command="ApplicationCommands.Open" 
   CanExecute="CommandCanExecute" Executed="CommandExecuted" /> 
     
   <CommandBinding Command="ApplicationCommands.Close" 
   CanExecute="CommandCanExecute" Executed="CommandExecuted" />

2. In the code implement the event Handlers.

      1:  Sub CommandExecuted(ByVal sender As Object, ByVal e As ExecutedRoutedEventArgs)

      2:  ‘Add the commands to be executed.

      3:  If e.Command.Equals(ApplicationCommands.Open) Then

      4:  MessageBox.Show(”Open Menu item clicked”)

      5:  ElseIf e.Command.Equals(ApplicationCommands.Close) Then

      6:  MessageBox.Show(”Close menu item clicked”)

      7:  End If

      8:  End Sub

      9:  Sub CommandCanExecute(ByVal sender As Object, ByVal e As CanExecuteRoutedEventArgs)

     10:  e.CanExecute = True ‘I am always returning true, based on this the menu item will enabled / disabled

     11:  End Sub

3. Assign the Commands to the Command property of our menu items.
   

   <MenuItem Command="ApplicationCommands.Open" >
   <Separator />
   <MenuItem Command="ApplicationCommands.Close" />

   Compile it run it. You will see “Ctrl + O” added to the right side Open menu item.

   You can see Ctrl + O added into the Open Menu item(Screenshot)

Happy WPF Programming :)

Few days back, I got a requirement to implement Free Hand drawing in .Net. I searched a lot but I didn’t get any good solution, the one I found from code project was Invalidating the picture box every time. So today I got a solution, it not seems to be a perfect solution because Paint events occurs, we need to re-paint the whole lines again.

I am attaching the code here. I will update the post once I get some perfect solution for this.

Private m_Drawing As Boolean = False
    Private m_List As List(Of Point) = Nothing
    Private Sub MyPic_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyPic.MouseDown
        If e.Button = Windows.Forms.MouseButtons.Left Then
            m_Drawing = True
        End If
    End Sub
    Private Sub MyPic_MouseUp(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyPic.MouseUp
        If m_Drawing AndAlso m_List IsNot Nothing Then
            If m_List.Count >= 2 Then
                MyPic.CreateGraphics.DrawLines(New Pen(Color.Blue, 1), m_List.ToArray())
            End If
            m_Drawing = False
            m_List.Clear()
        End If
    End Sub

    Private Sub MyPic_MouseMove(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles MyPic.MouseMove
        If m_List IsNot Nothing AndAlso m_Drawing Then
            m_List.Add(e.Location)
        End If
    End Sub
    Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        m_List = New List(Of Point)
    End Sub