“在Tab之间使用TabIndex拖动”

Question

问题

在我的使用.NET 4.5的Windows Phone 8 C＃/ XAML应用程序中我正在尝试通过表单“ iteite”。换句话说，当用户按下“ Enter”键时，焦点将更改为另一个TextBox或PasswordBox。

现在如何查看我的代码

XAML：

<TextBox TabIndex="0" KeyDown="TextBox_KeyDown"/>
<TextBox TabIndex="1" KeyDown="TextBox_KeyDown"/>
<TextBox TabIndex="2" KeyDown="TextBox_KeyDown"/>
<TextBox TabIndex="3" KeyDown="TextBox_KeyDown"/>
<TextBox TabIndex="4" KeyDown="TextBox_KeyDown"/>
....

C＃背后的代码：

using System.Windows.Input;

private void TextBox_KeyDown(object sender, System.Windows.Input.KeyEventArgs e)
{
    if (e.Key.Equals(Key.Enter))
    {
        int index = ((TextBox)sender).TabIndex + 1;
        //and here is what I've been missing
        //basically the code to select next tabindex
        //and set focus on it using Focus() method...
    }
}    

问题

1. 如何通过TABINDEX选择要关注的下一个元素？我知道我应该使用LINQ来选择用户控件中的所有文本框，然后选择带有tabindex索引的文本框。我正在慢慢地自己弄清楚（也通过与评论者讨论），但是由于花了我很长时间，所以我写了一个问题：）

*（另外，我不确定如何命名该问题，如果您认为您的名字更合适，可以随时重命名）

基于SACHA答案的解决方案

LayoutRoot是用户控件的主网格

    private void TextBox_KeyDown(object sender, System.Windows.Input.KeyEventArgs e)
    {
        if (e.Key.Equals(Key.Enter))
        {
            int index = ((TextBox)sender).TabIndex + 1;
            var nextBox = LayoutRoot.Children.OfType<TextBox>().FirstOrDefault((x) => { return x.TabIndex == index; });

            if (nextBox != null)
            {
                nextBox.Focus();
            }
        }
    }

非常感谢！ ：）

Answer 1

这是可能的实现。

<StackPanel x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0"
            >
    <TextBox TabIndex="0" KeyDown="OnKeyDown"/>
    <TextBox TabIndex="1" KeyDown="OnKeyDown"/>
    <TextBox TabIndex="2" KeyDown="OnKeyDown"/>
    <TextBox TabIndex="3" KeyDown="OnKeyDown"/>
    <TextBox TabIndex="4" KeyDown="OnKeyDown"/>
</StackPanel>

此下一个代码假定ContentPanel仅包含TextBox。您可以在其中添加更多智能代码...

private void OnKeyDown(object sender, KeyEventArgs e)
{
    if (e.Key.Equals(Key.Enter))
    {
        var txtBox = sender as TextBox;
        var index = txtBox.TabIndex;

        var nextTextBox = ContentPanel.Children.Cast<TextBox>().FirstOrDefault(t => t.TabIndex == index + 1);

        if (nextTextBox != null)
        {
            nextTextBox.Focus();
        }
    }
}

Answer 2

如果它对任何人都有帮助，在8.1（不知道它是否也适用于8）中，您可以这样做：

private void OnKeyDown(object sender, KeyEventArgs e)
{
    if (e.Key.Equals(Key.Enter))
    {
        FocusManager.TryMoveFocus(FocusNavigationDirection.Next);
    }
}

Answer 3

您甚至都不需要命名ContentPanel：

private void OnKeyDown(object sender, KeyEventArgs e)
{
    if (e.Key.Equals(Key.Enter))
    {
        var currentBox = (TextBox)sender;
        var container = currentBox.Parent;
        var index = currentBox.TabIndex + 1;
        var nextBox = container.ChildrenOfType<TextBox>().FirstOrDefault(box => box.TabIndex == index);

        if (nextBox != null)
        {
            nextBox.Focus();
        }
    }
}

Answer 4

protected void FocusOnTheNextTabIndex(object sender, FocusEventArgs e)
        {

            int nextIndex = e.VisualElement.TabIndex + 1;
            var element = sender as Element;
            View nextElement = VerifyParent(element, nextIndex);
            if (nextElement != null)
                nextElement.Focus();
        }

 public View VerifyParent(Element element, int index)
        {
            var parent = element.Parent;
            if (parent.GetType() == typeof(StackLayout))
            {
                var stackParent = parent as StackLayout;
                var response = VerifyChildren(stackParent, index);
                if (response != null)
                    return response;
                else
                    return VerifyParent(parent, index);
            }
            return null;
        }

        public View VerifyChildren(StackLayout stackLayout, int index)
        {
            foreach (View view in stackLayout.Children)
            {
                if (view.TabIndex == index)
                    return view;
                else if (view.GetType() == typeof(StackLayout))
                {
                    var stack = view as StackLayout;
                    if (stack.Children.Any())
                    {
                        var response = VerifyChildren(stack, index);
                        if (response != null)
                            return response;
                    }
                }
            }
            return null;
        }