从 wpf 客户端验证 ViewModel 中的 Entity Framework 对象

Question

在我的 WPF MVVM-Light ViewModel class 中，我有一个属性，这是一个来自 EntityFramework 6

的 EntityObject

    public Client Client
    {
        get { return client; }
        set
        {
            client = value;
            this.RaisePropertyChanged(() => this.Client);
        }
    }

部分客户端class：

[MetadataType(typeof(ClientMetadata))]
[CustomValidation(typeof(ClientValidator), "ClientValidation")]
public partial class Client
{
    public sealed class ClientMetadata
    {
        [Display(ResourceType = typeof(CaptionResources), Name = "Name")]
        public string Name { get; set; }
    }
}

它绑定到视图中的许多控件，例如：

            <TextBox TextWrapping="Wrap" Margin="5" Height="36" Text="{Binding Client.Name, Mode=TwoWay, ValidatesOnDataErrors=True, NotifyOnValidationError=True, NotifyOnSourceUpdated=True}" TabIndex="1"
                     Validation.ErrorTemplate="{StaticResource ImagedErrorTemplate}"/>

如何在视图上显示验证结果？我已经在我的 ViewModel 中实现了 INotifyDataErrorInfo, IValidationErrors 个接口。我已经有一个验证对象和 returns 验证错误的方法：

    private bool Validate()
    {
        var errors = new Dictionary<string, string>();

        if (!IsValid<Client, Client.ClientMetadata>(this.Client, ref errors))
        {
            foreach (var error in errors)
            {

                this.RaiseErrorsChanged("Client." + error.Key);
                this.RaisePropertyChanged(string.Format("Client.{0}", error.Key));
            }

            return false;
        }

        return true;
    }

但我仍然无法在视图中获取此信息。我的错误模板适用于 "standard" 属性：

<ControlTemplate x:Key="ImagedErrorTemplate">
    <DockPanel >
        <Border BorderBrush="Red" BorderThickness="1">
            <AdornedElementPlaceholder x:Name="adorner"/>
        </Border>
        <Image Source="../Assets/Images/warning.png" 
                            Height="20" 
                            Width="20"
                            ToolTip="{Binding ElementName=adorner, Path=AdornedElement.(Validation.Errors)[0].ErrorContent}"/>
    </DockPanel>
</ControlTemplate>

没有 DTO 对象，有什么方法可以做到这一点吗？

提前致谢。

Answer 1

我已经通过在 EntityFramework 个对象上实现 INotifyDataErrorInfo 来做到这一点。

[MetadataType(typeof(ClientMetadata))]
[CustomValidation(typeof(ClientValidator), "ClientValidation")]
public partial class Client : INotifyDataErrorInfo
{
    private Dictionary<string, ICollection<string>> validationErrors = new Dictionary<string, ICollection<string>>();

    public sealed class ClientMetadata
    {
        [Display(ResourceType = typeof(CaptionResources), Name = "Name")]
        public string Name { get; set; }
    }

    public Dictionary<string, ICollection<string>> ValidationErrors
    {
        get
        {
            return this.validationErrors;
        }
        set
        {
            this.validationErrors = value;
        }
    }

    public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged;

    public IEnumerable GetErrors(string propertyName)
    {
        if (string.IsNullOrEmpty(propertyName) || !this.ValidationErrors.ContainsKey(propertyName))
        {
            return null;
        }

        return this.ValidationErrors[propertyName];
    }

    public bool HasErrors
    {
        get { return this.ValidationErrors.Count > 0; }
    }

    public void RaiseErrorsChanged(string propertyName)
    {
        if (this.ErrorsChanged != null)
        {
            this.ErrorsChanged(this, new DataErrorsChangedEventArgs(propertyName));
        }
    }

从 wpf 客户端验证 ViewModel 中的 Entity Framework 对象

Validate Entity Framework object in ViewModel from wpf client side

c#

validation

wpf

entity-framework

mvvm-light