Question

使用MVC Foolproof Validation时，是否可以进行自定义验证asynchronous？我想在自定义验证中从DbSet检索一个对象，以检查该对象是否存在。

这可能吗？如果没有，是否有解决办法可以达到相同的效果？

这是我的代码：

public class RequiredThumbnailAssetId : ModelAwareValidationAttribute
{
    static RequiredThumbnailAssetId() { Register.Attribute(typeof(RequiredThumbnailAssetId)); }
    public async override Task<bool> IsValid(object value, object container)
    {
        var model = (IGridViewItemWithAssetId)container;
        if (model.thumbnailAssetId <= 0)
        {
            return false;
        }
        CanFindLocationDatabaseContext db = new CanFindLocationDatabaseContext();
        Asset asset = await db.assets.FindAsync(model.thumbnailAssetId);
        if (asset == null)
        {
            return false;
        }
        return true;
    }
}

以下是我收到的错误：

＆＃39; CanFindLocation.CustomValidations.RequiredThumbnailAssetId.IsValid（对象，对象）＆＃39;：返回类型必须是＆＃39; bool＆＃39;匹配被覆盖的成员＆＃39; Foolproof.ModelAwareValidationAttribute.IsValid（object，object）＆＃39;

提前致谢。

Answer 1

您可以使用帖子How would I run an async Task<T> method synchronously?中定义的类，然后将您需要的覆盖和异步调用分离为单独的方法。这将允许您从异步请求中调用同步覆盖。

public class RequiredThumbnailAssetId : ModelAwareValidationAttribute
{
    static RequiredThumbnailAssetId() { Register.Attribute(typeof(RequiredThumbnailAssetId)); }

    public async override Task<bool> CheckValid(object value, object container)
    {
        var valid = AsyncHelpers.RunSync<bool>(() => isValid(value,container));
        return valid;
    }

    public override bool IsValid(object value, object container)
    {
        var model = (IGridViewItemWithAssetId)container;
        if (model.thumbnailAssetId <= 0)
        {
            return false;
        }
        CanFindLocationDatabaseContext db = new CanFindLocationDatabaseContext();

        Asset asset = await db.assets.FindAsync(model.thumbnailAssetId);

        if (asset == null)
        {
            return false;
        }
        return true;
    }

异步防呆验证

1 个答案: