有没有办法在绑定中检查SelectedIndex属性？ [英] Is there a way of checking SelectedIndex property in binding?

问题描述

我希望根据ComboBox中Item的选择禁用控件TextBox和PasswordBox。因为我使用TextBox和PasswordBox.so的IsEnabled属性绑定，如何检查绑定中的索引？这是XAML代码：

I want the controls TextBox and PasswordBox to be disabled based on selection of Item in ComboBox.for that I thougt of using IsEnabled Property binding of TextBox and PasswordBox.so,how can I check the index in binding?Here's XAML code:

<ComboBox Name="account_type"SelectionChanged="ComboBox_SelectionChanged">
    <ComboBoxItem IsSelected="True">Administrator</ComboBoxItem>
    <ComboBoxItem>Employee</ComboBoxItem>
</ComboBox
     ...
<TextBox Name="credentials" IsEnabled="{some binding}">
<PasswordBox Name="password" IsEnabled="{some binding}">

两个控件需要如果选择是Admin.Also，则没有PasswordBox的IsEnabled属性。

The two controls need to be disabled If selection is Admin.Also,there is no IsEnabled property for PasswordBox.

推荐答案

假设您要在第一次时禁用控件em>项目在 ComboBox 中被选中，然后绑定到 SelectedIndex 将起作用：

Assuming that you want to disable the controls when the first item in the ComboBox is selected, then binding to SelectedIndex will work:

<TextBox Name="credentials" IsEnabled="{Binding ElementName=account_type, Path=SelectedIndex}" />
<PasswordBox Name="password" IsEnabled="{Binding ElementName=account_type, Path=SelectedIndex}" />

这是因为绑定将尝试将值转换为布尔值; 0 将转换为 false ，其他任何内容都将转换为 true 。



对于更强大的解决方案，您需要绑定到 SelectedItem ，并且提供转换器将项目的值转换为布尔值。



或者，如果您使用MVVM，您可以使用相关逻辑公开 CredentialEntryEnabled 属性。当帐户类型属性发生更改时，您也会为 CredentialEntryEnabled 属性引发 PropertyChanged 事件。

This is because the binding will try to convert the value to a Boolean; 0 will be converted to false, and anything else will be converted to true.

For a more robust solution, you would need to bind to the SelectedItem, and provide a converter to turn the value of the item into a Boolean.

Alternatively, if you use MVVM, you could expose a CredentialEntryEnabled property with the relevant logic. When the account type property changed, you would raise the PropertyChanged event for the CredentialEntryEnabled property as well.

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