Question

我有一个这样的视图模型：

 public class BaseViewModelTech : INotifyPropertyChanged
{


    static string _TechnicianID;
    public string TechnicianID
    {
        get {                
            return _TechnicianID;
        }
        set {

            _TechnicianID = TechnicianID; 
            OnPropertyChanged("TechnicianID");
        }

    }

    static string _DeviceID;
    public string DeviceID
    {
        get
        {
            return _DeviceID;
        }
        set
        {
            _DeviceID = DeviceID;
            OnPropertyChanged("DeviceID");
        }

    }



    // In ViewModelBase.cs
    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string propertyName)
    {
        this.VerifyPropertyName(propertyName);

        PropertyChangedEventHandler handler = this.PropertyChanged;
        if (handler != null)
        {
            var e = new PropertyChangedEventArgs(propertyName);
            handler(this, e);
        }
    }

    [Conditional("DEBUG")]
    [DebuggerStepThrough]
    public void VerifyPropertyName(string propertyName)
    {
        // Verify that the property name matches a real,  
        // public, instance property on this object.
        if (TypeDescriptor.GetProperties(this)[propertyName] == null)
        {
            string msg = "Invalid property name: " + propertyName;
            Debug.Fail(msg);
        }
    }
}

我将它作为参数发送到我的xaml.cs

 public partial class BaseView   : Window{
  BaseViewModelTech  viewModel; 
        public BaseView  (BaseViewModelTech   vm)
        {
            InitializeComponent();
            viewModel = vm;
        }}

我写什么来通过xaml使用绑定来访问它？我没有理解多个例子。

Answer 1

稍微更改您的视图后面的代码：

public partial class BaseView   : Window
{
    BaseViewModelTech  viewModel; 

    public BaseView  (BaseViewModelTech   vm)
    {
        InitializeComponent();
        viewModel = vm;
        this.DataContext = vm;   // <----------- add this
    }
}

然后在你的XAML中你可以得到这样的东西：

<TextBlock Text="{Binding TechnicianID}" />

另请注意，在您的二传手中，您希望在>更改属性值之后执行通知，而不是之前：

set { _DeviceID = DeviceID; OnPropertyChanged("DeviceID"); // <------ this goes after the member variable change }

Answer 2

在您的情况下，由于vm实例是View的成员，因此您无法直接将ViewModel直接引用到xaml中。因此，您应该首先在代码隐藏中设置视图的DataContext：

  public partial class BaseView   : Window{
  BaseViewModelTech  viewModel; 
        public BaseView  (BaseViewModelTech   vm)
        {
            InitializeComponent();
            viewModel = vm;
            this.DataContext=viewModel;
        }}

然后在我的xaml.xaml中为例如标签：

    <Label Content="{Binding TechnicianID }"/>

从ViewModel获取属性

2 个答案: