With this command I search all the items of a url where he looks for 10 items, now I need with this command to select only the item from the fifth position,
Returning only one item, how can I do this using the command below, what changes should I make
private async Task<List<FeedItem>> ParseFeed(string rss)
{
return await Task.Run(() =>
{
var xdoc = XDocument.Parse(rss);
var id = 0;
return (from item in xdoc.Descendants("item")
let enclosure = item.Element("enclosure")
where enclosure != null
select new FeedItem
{
Title = (string)item.Element("title"),
Description = (string)item.Element("description"),
Link = (string)item.Element("link"),
PublishDate = DateTime.Parse((string)item.Element("pubDate")).ToUniversalTime().ToString("dd/MM/yyyy HH:mm:ss"),
Category = (string)item.Element("category"),
Mp3Url = (string)enclosure.Attribute("url"),
Image = (string)enclosure.Attribute("url"),
Color_category =Convert.ToString(int.Parse((string)item.Element("color")), 16).PadLeft(6, '0'),
Id = id++
}).ToList();
});
}
Use Skip() and Take()
return (from item in xdoc.Descendants("item")
...
}).Skip(4).Take(1).ToList();
Related
***ctx.Load(listItemCollection,
eachItem => eachItem.Include(
item => item,
item => item["Column1"],
item => item["Column2"]
));***
i have list of fields in a array of string instead of column1 and column2, how can i pass it through in include linq, not able to create proper lambda on runtime. i tried following ways but couldn't get success. Static befor loops works but thw fields added in loop fails as it doesn't evaluate string value in loop
***Expression<Func<ListItem, object>>[] paramss = new
Expression<Func<ListItem, object>>[length];
paramss[0] = x => x.ContentType;
paramss[1] = x => x["Title"];
count = 2;
foreach (string item in solConnDefModel.Columns)
{ paramss[count] = x => x[item];
count++;
}***
Please take a reference of below code:
List dlist = context.Web.Lists.GetByTitle("listname");
context.Load(dlist);
context.ExecuteQuery();
string[] fieldNames = { "Id", "Title", "num", "mStartDate" };
// Create the expression used to define the fields to be included
List<Expression<Func<ListItemCollection, object>>> fieldsToBeIncluded = new List<Expression<Func<ListItemCollection, object>>>();
foreach (string s in fieldNames)
{
fieldsToBeIncluded.Add(items => items.Include(item => item[s]));
}
// Initialize the collection of list items
var listItems = dlist.GetItems(new CamlQuery());
context.Load(listItems, fieldsToBeIncluded.ToArray());
context.ExecuteQuery();
You can hover on load method to see what type parameter it requires, then generate a corresponding one and pass it.
i have to create lambda expression at runtime. following code i was able to get expected value
Expression<Func<ListItem, object>>[] paramss = new Expression<Func<ListItem, object>>[length];
foreach (string item in Columns)
{
if (item.ToLower() != "contenttype")
{
ParameterExpression parameter = Expression.Parameter(typeof(ListItem), "x");
var propertyInfo = typeof(ListItem).GetMethod("get_Item");
var arguments = new List<Expression> { Expression.Constant(item) };
var expression = Expression.Call(parameter, propertyInfo, arguments);
var lambda = Expression.Lambda<Func<ListItem, object>>(expression, parameter);
paramss[count] = lambda;
}
else
{
paramss[count] = x => x.ContentType;
}
count++;
}
How would I go about changing my if statement and foreach to something cleaner in linq using select and where.
I've tried to make the if statement into a where clause and then use the select query as a replacement for the Foreach loop but that seem to have type issues and wasn't working.
{
StripeConfiguration.ApiKey = _appSettings.StripeSecretKey;
var profile = await _userManager.FindByIdAsync(customerServiceID);
var stripeId = profile.StripeAccountId;
if (stripeId == null)
throw new ArgumentException("No associated Stripe account found.");
List<PaymentMethodDto> result = new List<PaymentMethodDto>();
var options = new PaymentMethodListOptions
{
Customer = stripeId,
Type = "card",
};
var service = new PaymentMethodService();
var payments = await service.ListAsync(options);
if (payments != null && payments.Data?.Count > 0)
{
payments.Data.ForEach((x) =>
{
result.Add(
new PaymentMethodDto
{
Brand = x.Card.Brand,
LastDigits = x.Card.Last4,
StripeToken = x.Id,
CustomerID = x.CustomerId
});
});
}
return result;
}
Just do a regular Select.
List<PaymentMethodDto> result = payments.Data.Select(x => new PaymentMethodDto
{
Brand = x.Card.Brand,
LastDigits = x.Card.Last4,
StripeToken = x.Id,
CustomerID = x.CustomerId
})
.ToList();
If payments.Data has nothing in it, this will give you an empty list, which is what you want.
If payments is null, you'll get an exception, which I think if you think about it really hard is probably what you really want in that case too. Why would .ListAsync() yield a null value?
what is the correct syntax to write the second list? bookid and other fields are not recognizing
var bookssublist = from bookdetails in bookslist
join bookcategories in _context.BookCategories
on bookdetails.BookId equals bookcategories.BookId
where bookcategories.CategoryId==CategoryId
select new BookBasicInfo {
count = bookcount,
BookInfo = new List<BookInfo>()
{
BookId = bookdetails.BookId,
BookTitle = bookdetails.Title,
Images = bookdetails.ThumbnailImagePath,
PublishDate = bookdetails.PublishedDate,
AuthorList = bookdetails.BookAuthors.Select(q => q.Author.Author1).ToList(),
CategoryList =bookdetails.BookCategories.Select(q=>q.Category.CategoryName).ToList(),
}
};
You are using collection initializer in a wrong way. Actually, you forgot to pass an object of type BookInfo to the initializer.
BookInfo = new List<BookInfo>()
{
new BookInfo()
{
BookId = bookdetails.BookId,
BookTitle = bookdetails.Title,
Images = bookdetails.ThumbnailImagePath,
PublishDate = bookdetails.PublishedDate,
AuthorList = bookdetails.BookAuthors.Select(q => q.Author.Author1).ToList(),
CategoryList =bookdetails.BookCategories.Select(q=>q.Category.CategoryName).ToList()
}
}
I did a profile tracing to check what functions are taking long times , One of the method takes near 1 second and is called 10+ times and i guess it should be a candidate for review. I have included the method, Can anyone tell me how can it possible be improved.
[NonAction]
private ProductModel.ProductMiscModel PrepareProductMiscModel(Product product)
{
if (product == null)
throw new ArgumentNullException("product");
var model = new ProductModel.ProductMiscModel();
var productVariants = _productService.GetProductVariantsByProductId(product.Id);
var getManufactureImage = _manufacturerService.GetProductManufacturersByProductId(product.Id)
.Select(x =>
{
var m = x.Manufacturer.ToModel();
m.PictureModel.ImageUrl = _pictureService.GetPictureUrl(x.Manufacturer.PictureId, _mediaSetting.ManufacturerThumbPictureSize, true);
m.PictureModel.Title = string.Format(_localizationService.GetResource("Media.Manufacturer.ImageLinkTitleFormat"), m.Name);
m.PictureModel.AlternateText = string.Format(_localizationService.GetResource("Media.Manufacturer.ImageAlternateTextFormat"), m.Name);
return m;
})
.ToList();
model.manufactureName = getManufactureImage;
switch (productVariants.Count)
{
case 0:
{
//var productVariant = productVariants[0];
model.Sku = null;
model.ShowSku = false;
// model.attributeName = 0;
} break;
case 1:
//only one variant
{ var productVariant = productVariants[0];
model.Sku = productVariant.Sku; //null;
model.ShowSku = true;
// model.attributeName = _productAttributeService.GetProductVariantAttributesByProductVariantId(productVariant.Id);
model.productSpecification = _specificationAttributeService.GetProductSpecificationAttributesByProductId(productVariant.Product.Id);
}
break;
}
return model;
}
_manufactureService.GetProductManufactureByProductId
public virtual IList<ProductManufacturer> GetProductManufacturersByProductId(int productId, bool showHidden = false)
{
if (productId == 0)
return new List<ProductManufacturer>();
string key = string.Format(PRODUCTMANUFACTURERS_ALLBYPRODUCTID_KEY, showHidden, productId);
return _cacheManager.Get(key, () =>
{
var query = from pm in _productManufacturerRepository.Table
join m in _manufacturerRepository.Table on
pm.ManufacturerId equals m.Id
where pm.ProductId == productId &&
!m.Deleted &&
(showHidden || m.Published)
orderby pm.DisplayOrder
select pm;
var productManufacturers = query.ToList();
return productManufacturers;
});
}
Use StopWatch in the method to determine which part it is that takes long time.
you might want to include the picture url in the original list instead of traversing each item and call _pictureService.GetPictureUrl.
I am having trouble to return an IEnumerable and IList, I cant do it!
I am using EF 4 with POCOs
Here's the whole method:
//public IList<Genre> GetGenresByGame(int gameId)
public IEnumerable<Genre> GetGenresByGame(int gameId)
{
using(var ctx = new XContext())
{
var results =
from t0 in ctx.GameGenres
join t1 in ctx.GenreCultureDetails on t0.GenreId equals t1.GenreId
where t0.GameId == gameId && t1.CultureId == _cultureId
select new Genre
{
GenreId = t0.GenreId,
GenreName = t1.GenreName
};
return results.ToList();
}
}
I have tried different ways that I have found on the net.. but can't make it work!
Question 2:
I saw a screencast with Julie something, saying that "You should always return an ICollection" when using EF4.
Any thoughts about that ?
BR
EDIT:
When I load the page in Debug-mode i get these errors: The ObjectContext instance has been disposed and can no longer be used for operations that require a connection. OR The entity or complex type 'XModel.Genre' cannot be constructed in a LINQ to Entities query.
Genre must not be a L2EF type. Try this:
public IEnumerable<Genre> GetGenresByGame(int gameId)
{
using(var ctx = new XContext())
{
var resultList =
from t0 in ctx.GameGenres
join t1 in ctx.GenreCultureDetails on t0.GenreId equals t1.GenreId
where t0.GameId == gameId && t1.CultureId == _cultureId
select new { t0.GenreId, t1.GenreName };
var genres = resultList.AsEnumerable().Select(o => new Genre
{
GenreId = o.GenreId,
GenreName = o.GenreName
});
return genres.ToList();
}
}
First an foremost if Genre is in the database you should select it? If you have FKs from Genre->GenreCultureDetails let me know and I can update the below, but from the looks of it you could do it like this:
using(var ctx = new XContext())
{
var results =
from g in ctx.Genre
join gcd in ctx.GenreCultureDetails on g.GenreId equals gcd.GenreId
where g.GameId == gameId && gcd.CultureId == _cultureId
select g;
return result.ToList();
}
Alternatively continue down your path select them into an annoynmous type, and then copy them. You can use select instead of convertall if you please.
IList<Genre> returnMe = Null;
using(var ctx = new XContext())
{
var results =
from t0 in ctx.GameGenres
join t1 in ctx.GenreCultureDetails on t0.GenreId equals t1.GenreId
where t0.GameId == gameId && t1.CultureId == _cultureId
select new
{
GenreId = t0.GenreId,
GenreName = t1.GenreName
};
returnMe = results.ToList().ConvertAll(x=>new Genre(){
GenreId = x.GenreId,
GenreName = x.GenreName
}
);
}
return returnMe;