WPF：无法设置焦点 [英] WPF: Cannot set focus

问题描述

我想从PreviewTextInput处理程序中创建一个新的控件，并将焦点设置为它。但即使在新控件上调用Focus（）之后，光标仍旧在旧文本框中。
UserControl_PreviewTextInput被登记在该用户控件的处理程序包含该文本框如果这个事务。

 私人无效UserControl_PreviewTextInput（对象发件人，TextCompositionEventArgs e）
 {
 CodeLineControl el = new CodeLineControl（）; 
 container.Children.Insert（idx + 1，el）; 
 el.innerTextBox.Focus（）; 
 
 
 
 
 
 $ p CodeLineControl是这样定义的（简体）：
 
 
 < UserControl ..> 
< DockPanel Name =codelineBackground =AntiqueWhite> 
< TextBox Name =innerTextBox/> 
< / DockPanel> 
< / UserControl> 
  
 Focus对Iam没有一些限制吗？我不允许将Focus（）从PreviewTextInput处理程序中的TextBox移开？我不能将焦点设置在新创建的元素？
 
 
解决方案
 
创建一个延迟后呼吁关注该文本框一个DispatcherTimer 
 
I want that from the PreviewTextInput handler a new control is created and focus is set to it. But even after calling Focus() on the new control, the cursor is still in the old textbox. 
The handler UserControl_PreviewTextInput is registered on the UserControl which contains this textbox if this matters.
private void UserControl_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
            CodeLineControl el = new CodeLineControl();
            container.Children.Insert(idx+1, el);
            el.innerTextBox.Focus();
}
CodeLineControl is defined like that(simplified):
<UserControl ..>
    <DockPanel Name="codeline"  Background="AntiqueWhite" >           
         <TextBox Name="innerTextBox"/>      
    </DockPanel>  
</UserControl>
Are there some limitations on Focus() that Iam not awre about? Am I not allowed to move Focus() away from a TextBox from a PreviewTextInput handler? Can't I set the focus on newly created elements?
解决方案
Create a DispatcherTimer that calls Focus on that textbox after a delay

                        
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