c# – 在组合框中实现IDataErrorInfo

我设置了1个文本框和1个组合框,在运行程序时,第一个焦点在文本框上,当我按Tab键聚焦在我得到的组合框中时：

InvalidOperationException: ‘validationTooltip’ name cannot be found in the name scope of ‘System.Windows.Controls.ToolTip’.`

为了帮助你在这里帮助我,我的XAML的一部分：

<Window.DataContext>
    <ViewModels:MainWindowViewModel/>
</Window.DataContext>

<!-- Batch ID-->
<Label Content="Batch ID"
       Height="28" 
       Margin="64,52,191,0" VerticalAlignment="Top" />
<TextBox Name="txtBatchId" 
    Text="{Binding BatchId,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged,ValidatesOnDataErrors=True}"
    Margin="124,65,0" TabIndex="1" Height="26" VerticalAlignment="Top" />

<!-- Product -->
<Label Content="Product" 
    Height="28" Margin="54,81,0" VerticalAlignment="Top" />
<ComboBox Name="cmbProduct" 
    ItemsSource="{Binding Products}" 
    DisplayMemberPath="ProductName" 
    SelectedValuePath="ProductId"
    SelectedValue="{Binding SelecteProductId,ValidatesOnDataErrors=True}"  
    Height="23" Margin="124,0" VerticalAlignment="Top" TabIndex="2" />

这是用于数据绑定组合框的ProductModel.cs：

public class ProductModel
{
    public int ProductId {get;set;}
    public int ProductName {get;set;}

    public ProductModel(int prodId,string prodName)
    {
        ProductId = prodIdl;
        ProductName = prodName;
    }
}

这是实现INotifyPropertyChanged和IDataErrorInfo的MainWindowViewModel.cs：

public class MainWindowViewModel : ViewModelBase,IDataErrorInfo
{
    private string _batchId;
    public string BatchId
    {
        get { return _batchId; }
        set
        {
            _batchId = value;
            OnPropertyChanged("BatchId");
        }
    }

    private ObservableCollection<Product> _products = new ObservableCollection<Product>();
    public IEnumerable<Product> Products {
        get { return _products; }
    }

    private string _selectedProductId;
    public string SelectedProductId
    {
        get { return _selectedProductId; }
        set
        {
            _selectedProductId = value;
            OnPropertyChanged("SelectedProductId");
        }
    }

    public void PopulateProduct() { 
        .... 
    }

    public MainWindowViewModel()
    {
        PopulateProduct();
    }

    public string this[string columnName]
    {
        get
        {
            string result = string.Empty;
            switch (columnName)
            {
                case "SelectedProductId":
                    if (SelectedProductId == null || SelectedProductId == "0")
                    {
                        result = "Please select a product";
                    }
                    break;
                case "BatchId":
                    if (string.IsNullOrWhitespace(BatchId))
                    {
                        result = "Please input batch id";
                    }
                    break;
            }

            return result;
        }
    }

    public string Error { get; private set; }
}

任何帮助将受到高度赞赏.请让我知道我可以添加的任何内容,以使其更清晰.