如何在另一个事件中创建一个keydown事件？ [英] How do I make a keydown event inside another event?

问题描述

我希望能够退出我创建的新表单，但是由于我手动创建表单，因此在withevents中没有处理程序。所以，既然我无法弄清楚我的生活是如何接近我的形式，我提出了另一种可能的解决方案。



我认为我可以在填充新表单的事件中创建一个keydown事件。现在它不起作用，但我希望问一个人我是否在正确的轨道上，可能他们知道我需要改变什么？



这是我的代码：

 Dim dk As System.Windows.Forms.KeyEventArgs 
 dk = sender 
 if dk.KeyCode = Keys.Escape然后
 picform.Close（）
结束如果
 

我尝试了什么：



我尝试将dk值更改为整数并尝试将其更改为键值，没有人帮助过。

解决方案

将代码重构（提取）为新方法（Sub / Function）。然后，您可以从代码中的多个位置调用它。例如：



之前：

 公开 类 Form1 
 
 私有  Sub  Form1_KeyDown（发件人作为 对象，e  As  KeyEventArgs）句柄  MyBase  .KeyDown 
 
 ' 代码在这里做了一些事情！ 
 
 结束  Sub  
 
 结束 < span class =code-keyword> Class  

AFTER：

 公开 类 Form1 
 
 私人  Sub  Form1_KeyDown（sender  As   Object ，e < span class =code-keyword> As  KeyEventArgs）句柄  MyBase  .KeyDown 
 
 NewMethod（）
 
 结束  Sub  
 
  Sub  NewMethod（）
 
 ' 代码在这里做了一些事情！ 
 
 结束  Sub  
 
  Sub  OtherMethod（）
 
 NewMethod（）
 
 结束  Sub  
 
 结束 类 

更新了新要求：对于新要求，您需要使用 WithEvents 来捕获KeyDown事件。这是一个反映这一点的新示例。

< pre lang =vb> 公共 类 Form1

私有 Sub Button1_Click（发件人 As 对象，e As EventArgs）句柄 Button1.Click
OpenForm（）
结束 Sub

私人 WithEvents picform 作为 新表格

Sub OpenForm（）

picform.Height = 800
p icform.Width = 600
' picform。 FormBorderStyle = FormBorderStyle.None
picform.Show（）

结束 Sub

私有 Sub picform_KeyDown（sender 作为 对象，e As KeyEventArgs）句柄 picform.KeyDown

MsgBox（ Picformn以父表单，MsgBoxStyle.Exclamation获取的keydown事件

结束 Sub

结束 类

非常感谢到Graeme_Grants解决方案我能够弄清楚其余部分，我只需要一种方法来获得这个处理器。

 Private WithEvents picform As New表格
 
 Dim picform As New Form 
 picform.Controls.Add（expandpic）
 picform.Height = 800 
 picform.Width = 600 
'picform .FormBorderStyle = FormBorderStyle.None 
 picform.Show（）
 
 AddHandler picform.KeyDown，AddressOf picform_convert 
 
 End Sub 
 
 Private Sub picform_convert（ByVal sender As System.Object，ByVal e As KeyEventArgs）
 
 picform = CType（sender，Form）
 
如果e.KeyCode = Keys.Escape那么
 picform.Close（）
 picform.Dispose（）
 End if 
 
 End Sub 

只是想出了其余的，谢谢你的帮助。现在我知道如何调用一个withevent处理程序以供将来参考。

I want to be able to exit a new form I created, but since I manually made the form its does not have a handler in the withevents. So since I can not figure out for the life of me how to approach getting my form into the withevents, I came up with another possible solution.

I figured that I could make a keydown event inside the event that populates the new form. Right now it's not working, but I was hoping to ask someone if I am on the right track, and possibly if they know what I need to change?

Here is my code:

Dim dk As System.Windows.Forms.KeyEventArgs
     dk = sender
     If dk.KeyCode = Keys.Escape Then
             picform.Close()
         End If

What I have tried:

I have tried changing the dk value into an integer and also tried changing it to a key value, none have helped.

解决方案

Refactor (extract) the code into a new method (Sub/Function). Then you can call it from multiple places in your code. Example:

BEFORE:

Public Class Form1

    Private Sub Form1_KeyDown(sender As Object, e As KeyEventArgs) Handles MyBase.KeyDown

        ' code does something here!

    End Sub

End Class

AFTER:

Public Class Form1

    Private Sub Form1_KeyDown(sender As Object, e As KeyEventArgs) Handles MyBase.KeyDown

        NewMethod()

    End Sub

    Sub NewMethod()

        ' code does something here!

    End Sub

    Sub OtherMethod()

        NewMethod()

    End Sub

End Class

Updated with new requirement: For the new requirement, you need to use WithEvents to capture the KeyDown event.Here is a new example to reflect this.

Public Class Form1

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

    Private WithEvents picform As New Form

    Sub OpenForm()

        picform.Height = 800
        picform.Width = 600
        ' picform.FormBorderStyle = FormBorderStyle.None
        picform.Show()

    End Sub

    Private Sub picform_KeyDown(sender As Object, e As KeyEventArgs) Handles picform.KeyDown

        MsgBox("Picformn keydown event caputred in parent form", MsgBoxStyle.Exclamation)

    End Sub

End Class

So thanks to Graeme_Grants solution I was able to figure out the rest, I just needed a way to get the withevent handler.

 Private WithEvents picform As New Form

Dim picform As New Form
        picform.Controls.Add(expandpic)
        picform.Height = 800
            picform.Width = 600
        ' picform.FormBorderStyle = FormBorderStyle.None
        picform.Show()

        AddHandler picform.KeyDown, AddressOf picform_convert

    End Sub

    Private Sub picform_convert(ByVal sender As System.Object, ByVal e As KeyEventArgs)

        picform = CType(sender, Form)

        If e.KeyCode = Keys.Escape Then
            picform.Close()
            picform.Dispose()
        End If

    End Sub

Just figured out the rest, thanks for the help. now I know how to call forth an withevent handler for future reference.

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