Question

我有一个父表单，我从中创建另一个表单的实例。（子表单）

我正在尝试从子表单触发父表单上的事件。（我曾尝试在SO上阅读一些类似的问题，但他们要么在c＃中，要么对像我这样的菜鸟的解释太少。

父表：

Private Sub DataGridView1_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick

            Dim index As Integer = Convert.ToInt32(DataGridView1.CurrentCell.RowIndex)

            Dim frmjvauth As New frmjventry_Auth
            frmjvauth.Show()
            frmjvauth.txtjvnumver.Text = DataGridView1.CurrentRow.Cells("jvnumber").Value
            frmjvauth.showjv()
    End Sub

Private Sub child_Change(sender As Object, e As EventArgs)
        MsgBox("hey")
    End Sub

儿童表格：

Private Sub frmjventry_Auth_FormClosed(sender As System.Object, e As System.Windows.Forms.FormClosedEventArgs) Handles MyBase.FormClosed
    RaiseEvent child_Change(Nothing, Nothing)
End Sub

Answer 1

从班级外部触发活动取决于您的活动和班级的实施特定情况发生时事件引发，例如更改属性值，单击按钮等时。要触发该事件，您应该模拟发生的事件，例如，您应该为要触发其更改事件的属性设置值，或者例如对于按钮，您应该调用该按钮的PerformClick方法。

但总的来说，最好在父表单中创建一个公共方法，然后将逻辑放在那里，并从表单外部调用该方法。

例如，我想你需要触发按钮1的Click事件并拥有以下代码：

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    //Some logic here
End Sub

选项1

您可以添加公共方法并在那里移动逻辑，并在button1_Click中调用该方法：

Public Sub MyLogic()
    //Some logic here
End Sub

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    MyLogic()
End Sub

然后从外面，你可以这样简单地使用逻辑：

//I suppose f is an instance of your form
f.MyLogic()

选项2

您可以将Button1公开，转到设计师并选择Button1并将Modifier属性的值设置为public。然后，您可以在表单外部使用此代码：

//I suppose f is an instance of your form
f.Button1.PerformClick()

选项3

对于您的手工制作的活动，您可以在表单中创建一个公共方法来引发您的活动：

Public Event YourEvent()

Public Sub OnYourEvent()
    RaiseEvent YourEvent()
End Sub

然后以这种方式在形式之外使用它：

//I suppose f is an instance of your form
f.OnYourEvent()

<强>示例

以下是包含两种形式的示例：

'Here is the code for parent form
Public Class ParentFormClass
    Public Sub MyLogic()
        MessageBox.Show("My Logic is Running!")
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        MyLogic()
    End Sub    

    'This is the way that you pass an instance of parent to child
    Private Sub ShowChildFormButton_Click(sender As Object, e As EventArgs) Handles ShowChildFormButton.Click
        Dim f As New ChildFormClass(Me)
    End Sub
End Class

'Here is the code for child form
Public Class ChildFormClass
    Private MyParentForm As ParentFormClass

    Public Sub New(form As ParentFormClass)
        ' This call is required by the designer.
        InitializeComponent()
        ' Add any initialization after the InitializeComponent() call.
        MyParentForm = form
    End Sub

    Private Sub CallParentFormMethodButton_Click(sender As Object, e As EventArgs) Handles CallParentFormMethodButton.Click
        MyParentForm.MyLogic()
    End Sub 
End Class

Answer 2

向子表单添加公共事件，并在主表单的处理程序中调用例程。在筹集活动时也没有通过Nothing是一个坏主意。您应该将Me作为发送方对象传递，将新的EventArgs对象作为e。

传递

Public Class ChildForm
    Public Event OnChanged(ByVal sender As Object, ByVal e As EventArgs)

    Private Sub frmjventry_Auth_FormClosed(sender As Object, e As EventArgs) Handles frmjventry_Auth.FormClosed
        RaiseEvent OnChanged(Me, New EventArgs)
    End Sub
End Class

Public Class MainForm
    Private Sub ChildForm_OnChanged(sender As Object, e As EventArgs) Handles ChildForm.OnChanged
        DoSomething()
    End Sub

    Private Sub DoSomething()
        ...
    End Sub
End Class

如何从子表单触发父表单事件？

2 个答案: