我有 TextBox
控件和关联的计时器,它们在每次 KeyDown
或 MouseClick
事件时重新启动,并在 3 秒后根据键入的文本执行查询没有那些事件。到目前为止一切顺利。
但是我的一些文本框也有用户可以浏览的自动完成列表,但即使他们使用键盘箭头键,计时器也不会停止,并且在用户浏览列表的过程中会触发意外的查询。
问题:有没有办法检测自动完成列表何时显示,以便我可以暂停计时器或忽略其滴答声?
非常感谢!
最佳答案
您可以使用EnumThreadWindows
查找所有自动完成下拉窗口并检查其中是否有任何可见。自动完成下拉窗口类名称为Auto-Suggest Dropdown
。您可以使用GetClassName
方法获取枚举窗口的类名,然后使用 IsWindowVisible
方法检查窗口是否可见。
示例
在下面的示例中,我使用了一个计时器,就像您在问题中的代码中一样,并且在计时器的滴答事件中,我检查了是否打开了一个自动完成窗口,我在标题中显示了“打开”表单,否则显示“关闭”:
Delegate Function EnumThreadDelegate(hWnd As IntPtr, lParam As IntPtr) As Boolean
<System.Runtime.InteropServices.DllImport("user32.dll")> _
Shared Function EnumThreadWindows(dwThreadId As Integer, _
lpfn As EnumThreadDelegate, lParam As IntPtr) As Boolean
End Function
<System.Runtime.InteropServices.DllImport("user32.dll")> _
Shared Function GetClassName(ByVal hWnd As System.IntPtr,
lpClassName As System.Text.StringBuilder, _
nMaxCount As Integer) As Integer
End Function
<System.Runtime.InteropServices.DllImport("kernel32.dll")> _
Shared Function GetCurrentThreadId() As Integer
End Function
<System.Runtime.InteropServices.DllImport("user32.dll")> _
Shared Function IsWindowVisible(hWnd As IntPtr) As Boolean
End Function
Const AutoCompleteClassName As String = "Auto-Suggest Dropdown"
Function EnumThreadCallback(hWnd As IntPtr, lParam As IntPtr) As Boolean
Dim className As New System.Text.StringBuilder("", 256)
GetClassName(hWnd, className, 256)
If className.ToString() = AutoCompleteClassName AndAlso IsWindowVisible(hWnd) Then
AnAutoCOmpleteIsOpen = True
End If
Return True
End Function
Dim AnAutoCOmpleteIsOpen As Boolean = False
Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
AnAutoCOmpleteIsOpen = False
EnumThreadWindows(GetCurrentThreadId(), _
New EnumThreadDelegate(AddressOf Me.EnumThreadCallback), IntPtr.Zero)
If (AnAutoCOmpleteIsOpen) Then
Me.Text = "Open"
Else
Me.Text = "Close"
End If
End Sub
关于.net - 检测文本框自动完成列表何时显示,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/40912233/