WPF 简单绑定
我正在尝试将我的控制台应用程序转换为漂亮的 WPF GUI。我对这段代码有点困惑，想知道是否有人可以提供帮助？
在我的 xaml 中，我有这样的内容：
<CheckBox IsChecked="{Binding CL.LoggedIn}"></CheckBox>
尝试将复选框的值绑定到 CL.LoggedIn 的值。 CL是我引用的类库中的ConnectionLibrary.cs类。
在 xaml 页面的后面代码中，我声明 CL 如下：
public ConnectionLibrary CL = new ConnectionLibrary();
在连接库类中，我已将 :INotifyPropertyChanged 添加到类声明中，并添加了以下代码：
public event PropertyChangedEventHandler PropertyChanged;
// Create the OnPropertyChanged method to raise the event
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
我已将 LoggedIn 属性更改为现在如下所示：
private bool loggedIn;
public bool LoggedIn {
get { return loggedIn; }
set { loggedIn = value; OnPropertyChanged("LoggedIn"); }
}
但是，它并没有似乎在我的 xaml 中工作？我在输出窗口中没有收到任何绑定错误，但它没有正确反映 LoggedIn 的值。
有什么想法吗？
谢谢！
I'm trying to convert my console app to a nice WPF GUI. Am getting a little stuck on this code and was wondering if someone can help?
In my xaml I have this:
<CheckBox IsChecked="{Binding CL.LoggedIn}"></CheckBox>
to try and bind the value of the checkbox to the value of CL.LoggedIn. CL is my ConnectionLibrary.cs class in a referenced class library.
In the code behind for the xaml page i declare CL as follows :
public ConnectionLibrary CL = new ConnectionLibrary();
In the connection library class I have added :INotifyPropertyChanged to the class declaration and added the following code:
public event PropertyChangedEventHandler PropertyChanged;
// Create the OnPropertyChanged method to raise the event
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
I have changed the LoggedIn property to now look like this:
private bool loggedIn;
public bool LoggedIn {
get { return loggedIn; }
set { loggedIn = value; OnPropertyChanged("LoggedIn"); }
}
However, it doesnt seem to work in my xaml? I dont get any binding errors in the output window, but it doesnt reflect the value of LoggedIn correctly.
Any ideas?
Thanks!
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您是否设置了视图的数据上下文？
在 XAML 文件的代码隐藏中，您需要执行以下操作：
那么绑定是：
绑定将在 DataContext 中的对象上查找命名路径（即 LoggedIn）。
编辑：默认绑定是单向的，这意味着它只能从您的 ViewModel 进行更新。
对于可以输入数据的控件（即：TextBox、CheckBox...），您可以将Binding 设置为“TwoWay”。 Binding 表达式变为：
现在，每当 UI 中的 Checked 状态发生变化时，它都会反映在您的 ViewModel 中。
Have you set the datacontext of your view?
In the code-behind of your XAML file, you need to do:
then the binding is:
The binding will find the the named path (i.e. LoggedIn) on the object that is in the DataContext.
EDIT: The default binding is one-way, this means it only gets updated from your ViewModel.
For controls that can be inputed data (i.e: TextBox, CheckBox...) you can set the Binding as "TwoWay". The Binding expression becomes:
Now whenever the Checked state changes in the UI, it is reflected in your ViewModel.
当您像这样使用
Binding时，它会绑定到当前的DataContext，而不是页面本身。解决此问题的最简单方法是在页面构造函数的末尾设置
DataContext = this。修复此问题的正确方法是使用 MVVM。这意味着将
ConnectionLibrary放在另一个类的属性中，并将DataContext设置为另一个类。When you use
Bindinglike this, it binds to the currentDataContext, not to the page itself.The easiest way to fix this would be to set
DataContext = thisat the end of the constructor of the page.The proper way to fix it would be to use MVVM. That would mean having
ConnectionLibraryin a property of another class and set theDataContextto this other class.