我正在使用具有可编辑内容的代码构建GUI.当用户点击静态显示时,控件将换出允许编辑的控件.在某些情况下,显示控件(例如Label)被换出来用于一组控件,例如ComboBox和TextBox.
我想检测何时从我的可编辑控件组中丢失焦点,以便将界面从编辑器切换回该项的显示表示.@H_301_3@
例如,我可能在Panel1中有一个GUI(Panel2(Button1,Button2),Button3),我想检测何时从Panel2丢失焦点.我尝试了以下(F#代码)：@H_301_3@
open System.Windows
let button1 = Controls.Button(Content="1")
let button2 = Controls.Button(Content="2")
let button3 = Controls.Button(Content="3")
[<System.STAThreadAttribute>]
do
let panel1 = Controls.StackPanel()
let panel2 = Controls.StackPanel()
panel2.Children.Add button1 |> ignore
panel2.Children.Add button2 |> ignore
panel1.Children.Add panel2 |> ignore
panel1.Children.Add button3 |> ignore
panel2.LostFocus.Add(fun _ ->
printfn "Panel2 lost focus")
Application().Run(Window(Content=panel1))
|> ignore
单击button2之后单击button3时会触发panel2.LostFocus事件,正如预期的那样,因为焦点从panel1移出到button3.但是,即使panel2从未失去焦点,单击button1后单击button2也会触发它.@H_301_3@
阅读有关WPF焦点的MSDN文档我尝试添加：@H_301_3@
Input.FocusManager.SetIsFocusScope(panel2,true)
但这实际上使问题变得更糟！现在只有当焦点从panel2的一个子节点转移到另一个子节点而不是当panel2实际失去焦点时才会触发panel2.LostFocus事件.@H_301_3@
解决方法
感谢Twitter上的
Ian Voyce,我能够使用IsKeyboardFocusWithinChanged事件获得我需要的功能.这是一个演示：
open System.Windows
let Button x =
Controls.Button(Content=x,Width=64.0,Margin=Thickness 3.0)
let Panel ctrls =
let panel = Controls.StackPanel()
for ctrl in ctrls do
panel.Children.Add ctrl
|> ignore
panel
let label = Controls.Label(Content="Edit 12")
let button1 = Button "1"
let button2 = Button "2"
let button3 = Button "3"
let panel = Panel[button1; button2]
[<System.STAThreadAttribute>]
do
label.HorizontalContentAlignment <- HorizontalAlignment.Center
label.MouseLeftButtonDown.Add(fun _ ->
label.Content <- panel)
panel.IsKeyboardFocusWithinChanged.Add(fun e ->
if not(unBox e.NewValue) then
label.Content <- "Edit 12")
Application().Run(Window(Content=Panel[label :> UIElement; button3 :> UIElement]))
|> ignore
