Question

我有TextBox个控件和关联的计时器，它们会在每个KeyDown或MouseClick事件上重新启动，并在没有这些事件的情况下在3秒后根据键入的文本执行查询。到目前为止一切都很好。

但我的一些TextBox还有自动完成列表，用户可以浏览，但即使他们使用键盘箭头键，也不会停止计时器，并且在浏览列表的用户中间会触发意外查询。

问题：有没有办法检测自动填充列表何时显示，以便我可以暂停计时器或忽略其勾号？

非常感谢！

Answer 1

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，我在问题的代码中使用了一个类似于你的计时器，并且在计时器的tick事件中，我检查了是否有一个自动完成的窗口打开我显示＆＃34;开放＆＃34;在表格的标题中，否则显示＆＃34;关闭＆＃34;：

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

Answer 2

Reza Aghaei的方法翻译成C＃：

public delegate bool EnumThreadDelegate(IntPtr hwnd, IntPtr lParam);

[DllImport("kernel32.dll")]
public static extern uint GetCurrentThreadId();

[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool IsWindowVisible(IntPtr hWnd);

[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
public static extern int GetClassName(IntPtr hWnd, StringBuilder lpClassName, int nMaxCount);

[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool EnumThreadWindows(uint dwThreadId, EnumThreadDelegate lpfn, IntPtr lParam);

bool isAutoCompleteListOpen = false;
EnumThreadDelegate callback = (IntPtr hwnd, IntPtr lParam) =>
{
    var cn = new StringBuilder("", 256);
    GetClassName(hwnd, cn, 256);
    if (cn.ToString() == "Auto-Suggest Dropdown" && IsWindowVisible(hwnd)) {
        isAutoCompleteListOpen = true;
        return false;
    }
    return true;
};

EnumThreadWindows(GetCurrentThreadId(), callback, IntPtr.Zero);
return isAutoCompleteListOpen;

为获得更好的性能，这里我们在找到打开列表后在回调中返回false，这将停止枚举。

检测TextBox自动完成列表何时显示

2 个答案: