我的 MVVM 模式不工作......为什么？

Question

在这个例子中，我尝试开发一个简单的工具来为客户管理软件许可证。它是在 C# WPF 中实现的，中心设计模式基于 MVVM 范例（表示层和 logic/data 层与 INotifyPropertyChanged、ICommand 和其他东西的分离）。

为什么无法动态绑定 XAML 中的属性？请查看末尾的附加链接以获取更多信息。

感谢您的帮助！

菲利克斯

我的相关观点（XAML）：

<DataGrid ItemsScource="{Binding Licenses}" SelectedItem="{Binding SelectedLicense}">
            <DataGrid.Columns>
                <DataGridTextColumn Binding="{Binding CustomerConverted}" Header="Customer"/>
                <DataGridTextColumn Binding="{Binding LicenseNoConverted}" Header="License no."/>
                <DataGridTextColumn Binding="{Binding LicenseKey}" Header="License key"/>
                <DataGridTextColumn Binding="{Binding LastActivation}" Header="Last activated ver."/>
                <DataGridTextColumn Binding="{Binding TypeConverted}"/>
            </DataGrid.Columns>
        </DataGrid>

代码隐藏

public partial class WMain : Window {
    public WMain() { 
        InitializeComponent();

        //construct ViewModel (works fine, all properties are consistent)
        WMainCtrl ctrl = new WMainCtrl(); 

        //set data context in code behind (XAML-bindings are not working)
        this.DataContext = ctrl;

        //that works instead... why?
        //c_dgLicenses.ItemsSource = ctrl.Licenses;        
    }
}

视图模型：

public class WMainCtrl : BaseCtrl {

    public WMainCtrl() {
        try {
            //init data
            License.selectAndConvertData();
        } catch (Exception exc) {
            throw exc;
        }
    }

    //this works, the collection is definitely filled 
    internal ObservableCollection<License> Licenses { get { return License.Obscol; } }

    private License _selectedLicense;
    public License SelectedLicense {
        get {
            if (_selectedLicense == null) {
                if (Licenses.Count == 0) {
                    return null;
                }
                return Licenses[0];
            } else
            return _selectedLicense;
        }
        set {
            if (_selectedLicense != value) {
                _selectedLicense = value;
                try {
                    Console.WriteLine(SelectedLicense.LicenseKey);
                } catch (Exception) {}
                OnPropertyChanged();
            }
        }
    }
}

ViewModelBase 的相关部分：

    protected void OnPropertyChanged([CallerMemberName] string propertyName = null) {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null) {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
    public event PropertyChangedEventHandler PropertyChanged;

以下是一些详细信息：

Architecture (rough draft, no UML rules)

Screenshot: DataContext is set properly?!

Answer 1

您在 DataGrid 上输入错误的 ItemsSource：

DataGrid ItemsScource="{Binding Licenses}" SelectedItem="{Binding SelectedLicense}"

Answer 2

我的旧 ViewModel 属性（不工作）

internal ObservableCollection<License> Licenses { get { return License.Obscol; } }

我的新 ViewModel 属性（工作中）

public ObservableCollection<License> Licenses { get { return License.Obscol; } }

我的 MVVM 模式不工作......为什么？

My MVVM pattern is not working... Why?

c#

datacontext

xaml

binding

mvvm