如果 selecteditem not null 文本框变得可见

Question

我在 C# 中有一个 UWP 应用 XAML。
我有各种组合框和文本框。
我想用以下内容创建一个事件：当从 combo1 中选择一个组合框项目时，文本框变得可见。

我知道组合框属性是可见性：Visble/collapsed 不确定如何将其合并到我的活动中，因为我无法获得 textbox.visibility 属性上班

private void ComboboxItem_Chosen(object sender, RoutedEventArgs e)
    {
        if (combobox.SelectedText != null)
        {
            txttnumber.Visibility ??
        }
        else
        {
            combobox.Visibility ??
        }
    }

Answer 1

你可以这样完成

private void ComboboxItem_Chosen(object sender, RoutedEventArgs e)
 { 
if (combobox.SelectedText != null)
 { txttnumber.Visibility =Visibility.Visible;
 } 
else 
{ combobox.Visibility =Visibility.Collapsed; 
}
 }

Answer 2

System.Windows 下的 Visibility 将允许您更改对象的可见性。你可以设置它

Visible : Display the element.

Hidden : Do not display the element, but reserve space for the element in layout.

Collapsed : Do not display the element, and do not reserve space for it in layout. Elements that have a Visibility value of Collapsed do not occupy any layout space. By default, elements are Visible.

所以在你的情况下，你应该像下面这样使用：

private void ComboboxItem_Chosen(object sender, RoutedEventArgs e)
{
    if (combobox.SelectedText != null)
    {
        txttnumber.Visibility = Visibility.Visible;
    }
    else
    {
        combobox.Visibility = Visibility.Collapsed;
    }
}

如果 selecteditem not null 文本框变得可见

If selecteditem not null textbox becomes visible

c#

combobox

uwp-xaml