vb.net – 没有使用.NET WinForms触发的KeyDown事件？

我已经在表单属性中将KeyPreview设置为true

我正在开发一个小程序,我遇到一个问题,当我按下并释放任何箭头键时,组件盒内部的某些控件似乎没有触发我的表单上的KeyDown事件,只是KeyUp事件.我的代码是否有问题可能导致此问题？

具体来说,我在表单上启用了KeyPreview,并在两个子程序中的e.SuppressKeyPress = True上设置断点,只有frmMain_KeyUp的断点点击断点.

我添加了两个GroupBox事件,希望可以缓解这个问题,但没有这样的运气.但是,我在表单上有一个自定义控件,专门编码忽略这些按键,代码按预期工作.

Private Sub frmMain_KeyDown(ByVal sender As Object,ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown,GroupBox1.KeyDown,GroupBox2.KeyDown
      e.SuppressKeyPress = True
      Select Case e.KeyCode
          Case Keys.Left
              ScrollDir = ScrollDir Or 1
          Case Keys.Right
              ScrollDir = ScrollDir Or 2
          Case Keys.Down
              ScrollDir = ScrollDir Or 4
          Case Keys.Up
              ScrollDir = ScrollDir Or 8
          Case Else
              e.SuppressKeyPress = False
      End Select
      tScroll.Enabled = True
      tScroll_Tick(Nothing,Nothing)
  End Sub

  Private Sub frmMain_KeyUp(ByVal sender As Object,ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyUp,GroupBox1.KeyUp,GroupBox2.KeyUp

      e.SuppressKeyPress = True
      Select Case e.KeyCode
          Case Keys.Left
              ScrollDir = ScrollDir And (Not 1)
          Case Keys.Right
              ScrollDir = ScrollDir And (Not 2)
          Case Keys.Down
              ScrollDir = ScrollDir And (Not 4)
          Case Keys.Up
              ScrollDir = ScrollDir And (Not 8)
          Case Else
              e.SuppressKeyPress = False
      End Select
      If ScrollDir = 0 Then tScroll.Enabled = False
  End Sub

用户控件中“忽略”按键的代码如下：

Private Sub TileDropDown_KeyDown(ByVal sender As Object,ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
        If e.KeyValue = 40 OrElse e.KeyValue = 38 OrElse e.KeyValue = 39 OrElse e.KeyValue = 37 Then

            e.SuppressKeyPress = True
        End If
    End Sub

某些控件拦截keydown事件中的箭头键,但不在keyup事件中.一种解决方案是派生控件类并重写ProcessCmdKey：

Protected Overrides Function ProcessCmdKey(ByRef msg As Message,ByVal keydata As Keys) As Boolean

If keydata = Keys.Right Or keydata = Keys.Left Or keydata = Keys.Up Or keydata = Keys.Down Then
  OnKeyDown(New KeyEventArgs(keydata))
  ProcessCmdKey = True
Else
  ProcessCmdKey = MyBase.ProcessCmdKey(msg,keydata)
  End If
End Function

原文链接：https://www.f2er.com/vb/255894.html

vb.net – 没有使用.NET WinForms触发的KeyDown事件？

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