I have a custom menu control in the main window of my WPF application. In main window, I have a frame. I want to change the page in this frame based on the selection in the custom menu control. Below is the code I tried.
Private Sub NominationMenuItem_Click(sender As Object, e As RoutedEventArgs)
Dim parentWindow As Window
parentWindow = Application.Current.MainWindow
parentWindow.MainFrame.Navigate(New NominationSearch)
End Sub
I know that I can't directly access "MainFrame" control using the "parentWindow" object. How do I rewrite the last line to get a reference to the existing frame object.
It's not appropriate for UserControl to manipulate it's parent. You should let your MainWindow to listen for NominationMenuItem changes via events and then MainWindow itself do the navigation.
So first you need to define an event in your UserControl:
Public Event NominationMenuItemChanged As RoutedEventHandler
Private Sub NominationMenuItem_Click(sender As Object, e As RoutedEventArgs)
RaiseEvent NominationMenuItemChanged(Me, New RoutedEventArgs())
End Sub
And then listen to this event in your MainWindow:
Public Sub MainWindow()
AddHandler MyUserControl.NominationMenuItemChanged, AddressOf UC_NominationMenuItemChanged
End Sub
Private Sub UC_NominationMenuItemChanged(sender As Object, e As RoutedEventArgs)
MainFrame.Navigate(MyUserControl.NominationSearch)
End Sub
Related
I have a XamDataGrid in my MainWindow which has a Public Shared List(Of Artikelstammdaten) as DataSource. After opening a few other forms I want to add more data to the XamDataGrid with a button click. I thought the easiest way would be just to update the DataSource, but I get an Error:
The reference to an unreleased member requires an object reference.
This is what I have tried:
Private Sub Add_Click(sender As Object, e As RoutedEventArgs)
Dim update = MainWindow.listArtikelstammdaten.Concat(CType(Import.ComparedAccessData, IEnumerable(Of Artikelstammdaten)))
dgArticleMasterData.DataSource = update
Me.Close()
End Sub
If dgArticleMasterData is defined in the MainWindow class, you need to get a reference to the MainWindow instance to be able to access it.
You should be able to find it in the Application.Current.Windows collection:
Private Sub Add_Click(sender As Object, e As RoutedEventArgs)
Dim update = MainWindow.listArtikelstammdaten.Concat(CType(Import.ComparedAccessData, IEnumerable(Of Artikelstammdaten)))
Dim window = Application.Current.Windows.OfType(Of MainWindow).FirstOrDefault()
If window IsNot Nothing Then
window.dgArticleMasterData.DataSource = update
End If
Me.Close()
End Sub
I have a usercontrol that contains a spread and I have this methods
Public Event DOBLECLICK()
Public Sub sp1_CellDoubleClick(sender As Object, e As FarPoint.Win.Spread.CellClickEventArgs)
RaiseEvent DOBLECLICK()
End Sub
and in the mainwindow.xaml in the function MainWindow_Loaded I have:
AddHandler host.sp1.CellDoubleClick, AddressOf host.sp1_CellDoubleClick
my question is, how can i use the event of double click and when clicked i hide the windowsformhost i know that i can hide it whit
WinFormsHost.Visibility = Windows.Visibility.Hidden but how to when clicked the doubleclick on the spread.
finally i got it,
in the user control put this:
Public Event Dobleclick()
Private Sub sp1_CellDoubleClick(sender As Object, e As FarPoint.Win.Spread.CellClickEventArgs) Handles spEmpresas.CellDoubleClick
RaiseEvent Dobleclick()
End Sub
and in the MainWindow.xaml:
Imports nameofyourprogram.Control
Public Class MainWindow
Dim host As New nameofyourprogram.Control
Public Sub MainWindow_Loaded(sender As Object, e As RoutedEventArgs) Handles Me.Loaded
AddHandler host.Dobleclick, AddressOf doubleclick
end sub
Sub doubleclick()
msgbox("now you can work whit and event in your mainwindow ")
'after this message i want to hide my windownforhost
WinFormsHost.Visibility = Windows.Visibility.Hidden
end sub
End Class
I have a wpf Custom Control which is now raising custom events. In a test project that I have created to test the ongoing development of the control I have placed a copy of my new custom control on the main window.
In the properties dialog for said control I can see my new event and I can type in the name for a handler for it in the code behind the main window and it's not only created for me but when I place a break point on it I see both the sender and my own event args raised in the control.
What I would now like to know Is what is the correct way to alert a viewmodel about that event respecting the principles of MVVM.
Below is the xaml markup for my custom control in the mainwindow of the test application
<WpfControls:VtlDataNavigator Name="vtlDn"
ItemsSource="{Binding Path=Orders}"
Grid.Row="1"
AddButtonVisibility="True"
CancelNewRecordButtonVisibility="True"
SaveButtonVisibility="True" />
The event I want to catch is called 'RecordControlButtonClicked' and this is the event automatically created in the mainwindow code behind
Private Sub MyCustomHandlerForControlEvent(sender As Object, e As ViewToLearn.WpfControls.VtlDataNavigatorEventArgs) Handles vtlDn.RecordControlButtonClicked
End Sub
So now what I'm after is the correct syntax in both the xaml and my new MainWindowViewModel to have this event transferred across to the viewmodel for handling (or suggestions as to the most efficient way to do this idf there is no direct route.
FYI I already have a relay command set up in the test application but the way that I've used it to bind commands in the past doesn't appear to be working with events.
Edit
One approach I've tried which appears to work is to add the following in the code behind of the main window's loaded event.
Class MainWindow
Public Sub New()
InitializeComponent
DataContext = New MainWindowViewModel
End Sub
Private Sub MainWindow_Loaded(sender As Object, e As RoutedEventArgs) Handles Me.Loaded
Dim mvm As MainWindowViewModel = DirectCast(DataContext, MainWindowViewModel)
mvm.vtldn = vtlDn
End Sub
End Class
and then add the following in the viewmodel;
Private _vtldn As ViewToLearn.WpfControls.VtlDataNavigator
Public Property vtldn As ViewToLearn.WpfControls.VtlDataNavigator
Get
Return _vtldn
End Get
Set(ByVal Value As ViewToLearn.WpfControls.VtlDataNavigator)
If (_vtldn Is Value) Then Return
If Not IsNothing(vtldn) Then
RemoveHandler vtldn.RecordControlButtonClicked, AddressOf MyCustomHandler
End If
_vtldn = Value
If Not IsNothing(vtldn) Then
AddHandler vtldn.RecordControlButtonClicked, AddressOf MyCustomHandler
End If
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(NameOf(vtldn)))
End Set
End Property
Private Sub MyCustomHandler(ByVal sender As Object, ByVal e As VtlDataNavigatorEventArgs)
'this does get called when buttons in the custom control are clicked
End Sub
However I'm acutely aware that this is not really 'pure' mvvm so if there are better ways to do this I'm open to suggestions.
So I have a class which contains a few controls for easy UI design and it has a custom event which is raised whenever the combo box inside the panel is changed:
Public Class BatInputLine
Inherits System.Windows.Forms.Panel
Public Event SelectionChanged As EventHandler
Protected Overridable Sub OnSelectionChanged(ByVal e As EventArgs)
RaiseEvent SelectionChanged(Me, e)
End Sub
Private Sub NameSet(sender As Object, e As EventArgs)
Handles_cboName.SelectedIndexChanged
PlayerName = _playerNames(_cboName.SelectedIndex)
SelectedIndex = _cboName.SelectedIndex
OnSelectionChanged(EventArgs.Empty)
End Sub
An array of these is declared and the user inputs a number according to how many of these they need on screen on a new Form.
ReDim _batInputs(GetNumberOfbatsmen())
I want to call a sub procedure whenever the SelectionChanged event is raised by any of the instances of BatInputLine in _batInputs(). If I try to write a handler e.g sub doSometing(sender as Object, e As EventArgs) Handles _batInputs(0).SelectionChanged I get an error saying that that the _batInput elements need to be declared with a WithEvents modifier, but I don't quite know how to do them.
a) How can I declare this array where all of the indexes get the WithEvents Modifier?
b) How can I assign a sub procedure that is called when these events are raised, which is in the new form?
Made use of the AddHandler keyword, which I didn't know existed.
for i = 0 to _batInputs.Length -1
AddHandler _batInputs(i).SelectionChanged, AddressOf HandleSelectionChangedEvent
next
Private Sub HandleSelectionChangedEvent
'do something
End Sub
I created a usercontrol with a treeview inside it. The treeview will be populated if I add nodes in the onload handler of the usercontrol. But after that(for example, I click a button in its parent form), the treeview will not refresh. I can see the nodes was updated in memory, but it just cannot display on the screen. I called refresh/update after adding nodes. Any suggestion is appreciated.
I put a quick test together based on your description and it seems to paint just fine.
UserControl1
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Partial Class UserControl1
Inherits System.Windows.Forms.UserControl
'UserControl overrides dispose to clean up the component list.
<System.Diagnostics.DebuggerNonUserCode()> _
Protected Overrides Sub Dispose(ByVal disposing As Boolean)
Try
If disposing AndAlso components IsNot Nothing Then
components.Dispose()
End If
Finally
MyBase.Dispose(disposing)
End Try
End Sub
'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer
'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
<System.Diagnostics.DebuggerStepThrough()> _
Private Sub InitializeComponent()
Me.TreeView1 = New System.Windows.Forms.TreeView
Me.SuspendLayout()
'
'TreeView1
'
Me.TreeView1.Dock = System.Windows.Forms.DockStyle.Fill
Me.TreeView1.Location = New System.Drawing.Point(0, 0)
Me.TreeView1.Name = "TreeView1"
Me.TreeView1.Size = New System.Drawing.Size(150, 150)
Me.TreeView1.TabIndex = 0
'
'UserControl1
'
Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
Me.Controls.Add(Me.TreeView1)
Me.Name = "UserControl1"
Me.ResumeLayout(False)
End Sub
Friend WithEvents TreeView1 As System.Windows.Forms.TreeView
End Class
Public Class UserControl1
Public Sub AddNewNode(ByVal text As System.String)
TreeView1.Nodes.Add(text)
End Sub
End Class
Put the usercontrol on a form with a button
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
UserControl11.AddNewNode(Now.ToString)
End Sub
End Class
If you are seeing proper painting as well then look at any graphics handling in the parent form then the usercontrol then the controls within the usercontrol. We really need more info.
Thank you, Dave. I figured it out. I put the usercontrol twice to my form by mistake(I cannot remember how I did it). And the one I operate is underneath the other one. That's why I cannot see it. Sorry for wasting your time.