如何将按钮绑定到VB.net中的方法

Question

我正在网上做一些研究，以了解如何做到这一点，但到目前为止我还没有做到。我认为我必须克服知识差距。

我有一个wpf按钮，当点击它时会执行它绑定的对象内部。

我想知道如何让按钮执行exampleObject.displayMessage（）。

VB.NET

Private Sub Window_Loaded(sender As System.Object, e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded

        Dim exObject As New exampleObject
        Grid1.DataContext = exObject 

End Sub

Public Class exampleObject
    Public ReadOnly Property testMessage As String
        Get
            Return "this is a test"
        End Get
    End Property

    Public Sub displayMessage()
        MsgBox(testMessage)
    End Sub
End Class

WPF

<Window x:Class="Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <Grid>
        <Grid Name="Grid1">
            <Button Content="Button" Name="Button1"/>
        </Grid>
    </Grid>
</Window>

Answer 1

要执行方法，您需要使用命令。请参阅以下实施。

<Grid>
    <Grid>
        <Grid Name="Grid1">
            <Button Content="Button" Name="Button1" Command="{Binding TestCommand}"/>
        </Grid>
    </Grid>
</Grid>


Class MainWindow 
    Private Sub Window_Loaded(sender As Object, e As RoutedEventArgs)
        Dim exObject As New exampleObject
        Grid1.DataContext = exObject
    End Sub
End Class

Public Class exampleObject
    Private m_TestCommand As ICommand
    Public Property TestCommand As ICommand
        Get
            Return m_TestCommand
        End Get
        Set(ByVal value As ICommand)
            m_TestCommand = value
        End Set
    End Property
Public Sub New()
    m_TestCommand = New DelegateCommand(AddressOf displayMessage, AddressOf CandisplayMessage)
End Sub

Public Sub displayMessage(ByVal param As Object)
    MsgBox(testMessage)
End Sub

Private Function CandisplayMessage(ByVal param As Object) As Boolean
    Return True
End Function

Public ReadOnly Property testMessage As String
    Get
            Return "this is a test"
        End Get
    End Property
End Class


Public Class DelegateCommand
    Implements ICommand

    Private m_canExecute As Func(Of Object, Boolean)
    Private m_executeAction As Action(Of Object)
    Private m_canExecuteCache As Boolean

    Public Event CanExecuteChanged(ByVal sender As Object, ByVal e As System.EventArgs) Implements ICommand.CanExecuteChanged

    Public Sub New(ByVal executeAction As Action(Of Object), ByVal canExecute As Func(Of Object, Boolean))
        Me.m_executeAction = executeAction
        Me.m_canExecute = canExecute
    End Sub

    Public Function CanExecute(ByVal parameter As Object) As Boolean Implements ICommand.CanExecute
        Dim temp As Boolean = m_canExecute(parameter)
        If m_canExecuteCache <> temp Then
            m_canExecuteCache = temp
            RaiseEvent CanExecuteChanged(Me, New EventArgs())
        End If
        Return m_canExecuteCache
    End Function

    Public Sub Execute(ByVal parameter As Object) Implements ICommand.Execute
        m_executeAction(parameter)
    End Sub

End Class

我从http://www.paulspatterson.com/mvvm-and-wpf-for-vb-net-%E2%80%93-part-5-%E2%80%93-delegating-commands/获得了委托命令。该网站提供了非常详细的信息。