在vb.net中使用AddHandler和AddressOF的问题 [英] Problem using AddHandler and AddressOF in vb.net

问题描述

我正在使用此代码：

 Dim img As Image 
 Private Sub SendMail_Load（sender as Object，e As EventArgs）处理MyBase .Load 
 For Each fi As FileInfo in New DirectoryInfo（" D：\ emojis \ 1"）。GetFiles（）
 Dim pbx As New PictureBox 
 pbx.Width = 32 
 pbx.Height = 32 
 pbx.Image = Image.FromFile（fi.FullName）
 AddHandler pbx.Click，AddressOf pbx_click 
 FlowLayoutPanel1.Controls.Add（pbx）
 
下一个
结束Sub 
 Friend Sub pbx_click（发送者作为对象，e作为EventArgs）
 img = pbx.Image 
 Clipboard.SetImage（img）
 bodytxt.Paste（）
 End Sub 

基本上我的动机是我想通过点击将图像添加到richtextbox（bodytxt）在formboxes（pbx）上生成的表单的加载事件。但是在pbx_click事件中我无法使用：image = pbx.image：It说PBX没有声明。所以我该如何解决？

解决方案

但是在pbx_click事件中我可以使用：image = pbx.image：它说PBX没有声明。所以我该如何修复它？

你已经在函数SendMail_Load中声明了变量PBX（ ），因此其使用仅限于该功能。如果你想从其他地方的代码中引用它，那么它应该在所有函数都可以访问的级别（例如，表单级别）声明。

https://docs.microsoft.com/en-us/dotnet/visual - 基本/编程导/语言的功能/声明元素/范围

I am using this code :

    Dim img As Image
    Private Sub SendMail_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        For Each fi As FileInfo In New DirectoryInfo("D:\emojis\1").GetFiles()
            Dim pbx As New PictureBox
            pbx.Width = 32
            pbx.Height = 32
            pbx.Image = Image.FromFile(fi.FullName)
            AddHandler pbx.Click, AddressOf pbx_click
            FlowLayoutPanel1.Controls.Add(pbx)

        Next
    End Sub
    Friend Sub pbx_click(sender As Object, e As EventArgs)
        img = pbx.Image
        Clipboard.SetImage(img)
        bodytxt.Paste()
    End Sub

Basically my motive is i want add image to a richtextbox(bodytxt) by clicking on pictureboxes(pbx)that are generated on form's load event.But in the pbx_click event i can't use : image=pbx.image : It says PBX NOT DECLARED.So how do i fix it?

解决方案

But in the pbx_click event i can't use : image=pbx.image : It says PBX NOT DECLARED.So how do i fix it?

You have declared the variable PBX within the function SendMail_Load(), so its usage is restricted to that function. If you want to refer to it from code in other places, then it should be declared at a level (eg, form level) where it is accessible to all functions.
https://docs.microsoft.com/en-us/dotnet/visual-basic/programming-guide/language-features/declared-elements/scope

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