Try within Linq query

Try within Linq query

Content Index :

Try within Linq query
Tag : chash , By : niel
Date : November 23 2020, 12:01 PM

This might help you try using a scope in the Select() method and a Where() to filter the null outputs:
        var result = ListOfFiles.Select(_s =>
                    return new ObjectA(_s);
                catch (Exception)
                    return null;

            }).Where(x => x != null).ToList();

No Comments Right Now !

Boards Message :
You Must Login Or Sign Up to Add Your Comments .

Share : facebook icon twitter icon

LINQ - How to make a linq query with left join, group by, where clause and order by in a single query

Tag : development , By : kameel
Date : March 29 2020, 07:55 AM
This might help you I have googled for four days but not found a single example which contains all three keywords in a single linq query.
Dim query = (From n In tblNseFo.AsEnumerable _
                            Where n!client_id = intClientID _
                            Group Join c In tblClient _
                            On n!client_id Equals c!client_id Into cs = Group _
                            From c In cs.DefaultIfEmpty _
                            Group n, c By _
                            c!client_name, n!instrument_group_id, n!trade_date Into gs = Group _
                            Order By trade_date _
                            Select New With { _
                                .client_name = client_name, _
                                .instrument_group_id = instrument_group_id, _
                                .trade_date = trade_date, _
                                .TotBuyQty = gs.Sum(Function(x) x.n!buy_qty), _
                                .TotSellQty = gs.Sum(Function(x) x.n!sell_qty), _
                                .TotBuyVal = gs.Sum(Function(x) x.n!buy_value) + gs.Sum(Function(x) x.n!buy_brokerage), _
                                .TotSellVal = gs.Sum(Function(x) x.n!sell_value) - gs.Sum(Function(x) x.n!sell_brokerage), _
                                .ProfitLoss = (gs.Sum(Function(x) x.n!sell_value) - gs.Sum(Function(x) x.n!sell_brokerage)) - _
                                              (gs.Sum(Function(x) x.n!buy_value) + gs.Sum(Function(x) x.n!buy_brokerage))})

Some confusion with Linq-to-Objects query operating on results of Linq-to-Entities query

Tag : development , By : Sigfrieg
Date : March 29 2020, 07:55 AM
wish of those help First context.Contacts is processed by the EF query provider which translates expressions (from IQueryable) into SQL.
Then, by AsEnumerable, the link with the EF query provider is broken and anything after that is linq to objects, working on the result set from the preceding statement.

Nesting Linq-to-Objects query within Linq-to-Entities query –what is happening under the covers?

Tag : development , By : Adam
Date : March 29 2020, 07:55 AM
help you fix your problem I've just tried this in LinqPad, and the generated SQL looks like:
-- Region Parameters
DECLARE @p0 Int = 5
DECLARE @p1 Int = 1
-- EndRegion
SELECT [t0].[ContactID], [t0].[Name]
FROM [Contacts] AS [t0]
WHERE ([t0].[ContactID] = @p0) OR ([t0].[ContactID] = @p1)
var numbers = new int[] { 1, 2, 3, 4, 5 };

int max = numbers.Max();
int first = numbers.FirstOrDefault();

var contacts = from c in context.Contacts
   where c.ContactID == max !| c.ContactID == first
   select c;

EntityFramework LINQ query count fails but query returns result. How to optimize LINQ query?

Tag : chash , By : Jarques
Date : March 29 2020, 07:55 AM
This might help you Not quite sure that's the problem, but at least let try to eliminate the potential effect of the so called Parameter Sniffing Problem by eliminating the dateStart / dateEnd parameters by manually building expression with constant values.
First, a little helper method:
using System;
using System.Linq;
using System.Linq.Expressions;

public static class QueryableUtils
    public static IQueryable<T> WhereBetween<T>(this IQueryable<T> source, Expression<Func<T, DateTime>> dateSelector, DateTime? startDate, DateTime? endDate)
        if (startDate == null && endDate == null) return source;
        var startCond = startDate != null ? Expression.GreaterThanOrEqual(dateSelector.Body, Expression.Constant(startDate.Value)) : null;
        var endCond = endDate != null ? Expression.LessThanOrEqual(dateSelector.Body, Expression.Constant(endDate.Value)) : null;
        var predicate = Expression.Lambda<Func<T, bool>>(
            startCond == null ? endCond : endCond == null ? startCond : Expression.AndAlso(startCond, endCond),
        return source.Where(predicate);
//if (dateStart.HasValue)
//    query = query.Where(e => e.outer.ValueDate >= dateStart.Value);
//if (dateEnd.HasValue)
//    query = query.Where(e => e.outer.ValueDate <= dateEnd.Value);
query = query.WhereBetween(e => e.outer.ValueDate, dateStart, dateEnd);

linq query insert exist query string into linq query

Tag : chash , By : Yolanda N. Ceron
Date : March 29 2020, 07:55 AM
Does that help I want to make the query follow the query string of the website but it cant be done in this way, is there any other option to do something like this? For example i can insert name,type,class in the query string but not every variable is need to search for the student , try this:
        var query = from c in db.Students select c;
        if (Request.QueryString["Name"] != null)
            name = Request.QueryString["Name"];
            query = query.Where(c => c.name == name);

        if (Request.QueryString["Type"] != null)
            type += Request.QueryString["Type"];
            query = query.Where(c => c.type == type);

        GridView1.DataSource = query.ToList()
Related Posts Related QUESTIONS :
  • Numeric Data Entry in WPF
  • Print a Winform/visual element
  • C# logic order and compiler behavior
  • When to use an extension method with lambda over LINQtoObjects to filter a collection?
  • How to make a button appear as if it is pressed?
  • C# and Arrow Keys
  • How do you resolve a domain name to an IP address with .NET/C#?
  • Should the folders in a solution match the namespace?
  • How can I evaluate C# code dynamically?
  • CSharpCodeProvider Compilation Performance
  • How can I create Prototype Methods (like JavaScript) in C#.Net?
  • DataTable Loop Performance Comparison
  • CSV string handling
  • What is the best way to do unit testing for ASP.NET 2.0 web pages?
  • High availability
  • What to use for Messaging with C#
  • Accessing a Dictionary.Keys Key through a numeric index
  • ConfigurationManager.AppSettings Performance Concerns
  • What Are Some Good .NET Profilers?
  • Is this a good way to determine OS Architecture?
  • How to create a tree-view preferences dialog type of interface in C#?
  • Searching directories for tons of files?
  • Can I have a method returning IEnumerator<T> and use it in a foreach loop?
  • Why can't I have abstract static methods in C#?
  • Displaying ad content from Respose.WriteFile()/ Response.ContentType
  • Convert integers to written numbers
  • Absolute path back to web-relative path
  • How can we generate getters and setters in Visual Studio?
  • Bringing Window to the Front in C# using Win32 API
  • Possible to "spin off" several GUI threads? (Not halting the system at Application.Run)
  • Reading a C/C++ data structure in C# from a byte array
  • How should I translate from screen space coordinates to image space coordinates in a WinForms PictureBox?
  • Setting Objects to Null/Nothing after use in .NET
  • Converting ARBG to RGB with alpha blending
  • Is it better to create Model classes or stick with generic database utility class?
  • Passing enum type to Converter with integer value
  • Pool of objects with objects that are already on the scene in advance
  • StatusBar text fade-out when binding using Caliburn.Micro
  • Queryfilter on ApplicationUser in OnModelCreating in ApplicationDbContext creates StackOverflowException
  • How to get record form a different table based on a value from first table with linq expression?
  • Show data in Grid from returned model
  • Using Attributes to Override Data Model Conventions
  • Basic OOP console calculator, result Error
  • Compositon and Repository pattern
  • Multiple using statements with if condition
  • How do i increase a number by 1 in every line that contain the number 1
  • Add binding to elements that are created in codebehind
  • How to add a column in an existing AspNetUsers table
  • Order a list of elements with another list of doubles
  • How to setup a NuGet package to copy content files to output build directory?
  • In SignalR Core using ChannelWriter: Do I need to call TryComplete twice if there's an exception?
  • C# GetProcessesByName: issue with colon
  • c# wpf | create complex object with user-defined name to Serialize into JSON
  • How can I get a instance of a generic list with reflection?
  • WPF XAML - Design time and visibility of textbox
  • EF Core and MySql query is too slow
  • Getting Registered App Display Name from an App Id
  • How to get all variables from a string
  • Delete entity with all childs connected
  • Azure Build agent cant´t find class library referance
  • shadow
    Privacy Policy - Terms - Contact Us © scrbit.com