包含vb.net事件参数的词条

vb.net中事件System.EventArgs的参数具体有什么？

e就是event事件，可以表示事件当前状态。

比如：在treeview控件的事件中，e.node表示节点。

相关问答

Q1: VB.net click事件后面的2个参数是什么意思

sender:发出该事件的控件

e 事件的参数

Private Sub but1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles but1.Click,but2.Click,but3.Click 这样就可以处理多个相同控件发出的相同事件

CType(sender,Button).Name 可以显示出发出该事件的控件名称,其他应用类似此句

Q2: vb.net 如何传递类参数

线程结束后利用委托生成事件返回，线程应用包括传入和传出参数。

Public Delegate Sub ThreadCallback(value As ThreadResult)

Public Class Form1

Private WithEvents _th_1 As Thread_1

Protected Overrides Sub OnLoad(e As System.EventArgs)

Dim value As ThreadObject

value.Index = 1

Me._th_1 = New Thread_1(Me)

Me._th_1.Run(value)

MyBase.OnLoad(e)

End Sub

Private Sub Thread_1_End(sender As Object, e As ThreadEventArgs) Handles _th_1.ThreadEnd

Me.TextBox1.Text = e.Result.Text

End Sub

End Class

Public Class Thread_1

Public Event ThreadEnd(sender As Object, e As ThreadEventArgs)

Private _control As Control

Sub New(control As Control)

Me._control = control

End Sub

Public Sub Run(value As Object)

Dim th As New Threading.Thread(AddressOf ThreadProc)

th.Start(value)

End Sub

Private Sub ThreadProc(obj As Object)

Dim value As ThreadObject = CType(obj, ThreadObject)

Dim result As ThreadResult = Nothing

If value.Index = 1 Then result.Text = "测试"

Dim callback As New ThreadCallback(AddressOf ThreadInvoke)

_control.Invoke(callback, result)

End Sub

Private Sub ThreadInvoke(value As ThreadResult)

RaiseEvent ThreadEnd(Me, New ThreadEventArgs(value))

End Sub

End Class

Public Structure ThreadObject

Public Index As Integer

'Public Rect As Rectangle

End Structure

Public Structure ThreadResult

Public Text As String

'Public Rect As Rectangle

End Structure

Public Class ThreadEventArgs

Inherits System.EventArgs

Private _result As ThreadResult

Public ReadOnly Property Result As ThreadResult

Get

Return _result

End Get

End Property

Sub New(value As ThreadResult)

Me._result = value

End Sub

End Class

Q3: VB.NET 中，定义sub的时候，byval后面可以定义事件的参数类型么？

括号里只能传参数，不能传过程和函数，形参的参数类型按需要写，不知道该写啥就不写，但是不写容易出错

你想在过程B内部调用A过程，直接call A就行

Q4: vb.net中的事件函数，怎样为（sender,e）中的e增加自定义的参数?

继承buttonvb.net事件参数，然后增加事件

并且自定义EventArg

思路vb.net事件参数：

class MyEventArg :EventArg

{

public long MyNum

{

set{ myNum = value;}

get{ return myNum; }

}

private long myNum ;

}

class MyButton:System.Windows.Forms.Button

{

public delegate void MyClick(object sender,MyEventArg e);

public event MyClick OnMyClick;

private MyEventArg myE = new MyEventarg();

protected override void OnClick(EventArgs e)

{

if(OnMyClick != null)

{

OnMyClick(null,myE);

}

base.OnClick(e);

}

}

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