vb.net传递参数损失的简单介绍

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VB.net 两个窗体之间传递参数

新窗体中写构造函数，然后调用。

比如你要调用的新窗体是From1.cs这个窗体，

public Form1(要传入的参数)

{

//把传入的参数传入窗体中

//执行窗体标准内容

}

然后在需要调用的地方调用

Form1 f = new Form1(传出的参数);

'--------Form1--------

Dim f2 As Form2

Private Sub Command1_Click()

Set f2 = New Form2

f2.Show vbModal

End Sub

'--------Form1 End--------

'--------Form2--------

Dim WithEvents f3 As Form3

Private Sub Command1_Click()

Set f3 = New Form3

f3.Show

End Sub

Public Sub f3_f2W()

Me.Command1.Caption = "f2W"

End Sub

'--------Form2 End--------

'--------Form3--------

Public Event f2W()

Private Sub Command1_Click()

RaiseEvent f2W

End Sub

'--------Form3 End--------

f.Show();

如此就能实现调用了。

关于VB.NET中-引用类型参数传递的问题

1.对象变量与对象本身是不同的，对象变量代表了对象真实数据在内存中的地址.

打个比方，“对象变量”就象你家的地址，“对象本身”就象你家。

你不能说你家的地址(xx路xx号xx房)就是你家，但是可以通过这个地址而找到你家。

2.传值的参数本身是被复制一份的，但这并不意味着它所代表的对象也被复制一份.

有如下一个函数:

Public

Function

Do_delete(ByVal

ps_usr_id

String)

Boolean

你在调用时可能这样调用:

dim

strID

string

strID

"kknd001"

Do_delete(strID)

then.....

当程序执行到Do_delete函数体里面时ps_usr_id变量其实是按照StrID的值而复制的一个变量。

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

vb.net 给委托的函数传递参数

两个参数：一个是数组名,一个是传递的长度

Function thename(ByVal imgFrom As Image) As String

thename = imgFrom.Name

End Function

Private Sub Image1_Click()

MsgBox thename(Image1)

End Sub

vb.net2005:2个form之间传递参数的问题，高手进

把form1设为启动项在form3中调用当然是空啊。因为这时候还没有发生form2vb.net传递参数损失的load事件。vb.net传递参数损失你可以在form1vb.net传递参数损失的load事件里面对form2vb.net传递参数损失的变量付值然后把form2对象传给form3vb.net传递参数损失，或者fom2里的变量设为静态的这样不用传对象