I am having a little problem with some homework. Here is the problem:Use the Invoice Class provided to create an array of Invoice Objects. Class Invoice includes four properties- a PartNumber (type integer), a PartDescription (type String), a Quantity of the item being purchased (type Integer), and a Price (type Decimal). Write a Console Application that performs the following queries on the array of Invoice objects and displays the results:
Use the Invoice Class provided to create an array of Invoice Objects. Class Invoice includes four properties- a PartNumber (type integer), a PartDescription (type String), a Quantity of the item being purchased (type Integer), and a Price (type Decimal). Write a Console Application that performs the following queries on the array of Invoice objects and displays the results:
a. Use LINQ to sort the Invoice Objects by PartNumber b. Use LINQ to sort the Invoice objects by Price c. Use LINQ to select the PartDescription and Quantity and sort the results by Quantity d. Use LINQ to select from each Invoice the PartDescrition and the value of the Invoice (i.e. Quantity * Price). Name the calculated column InvoiceTotal. Order the results by InvoiceTotal. e. Using the results of the LINQ query in Pard d, select the InvoiceTotals in the range of $200 to $500
I am pretty sure I have parts a, b, & c completed correctly. Or at least the provide the desired results. Part d I figured out how to multiply the 2 fields but can't create a new column for the result or figure out how to show the PartDescription with the multiplied result. Part c I think I can figure out when I get part d. I already coded what I think will work for part c.
Below are the 2 Objects the Invoice was given and not to be changed & the LINQ is the one I have been working on. Module LINQ Sub Main() ' array of invoices Dim invoices As Invoice() = { _ New Invoice("83", "Electric Sander", "7", 59.98), _ [Code] .....
Not sure if I am using the correct term, but it's not child/parent since they aren't nested objects. In my application I've got a User, UserUserGroup, and UserGroup objects which are pretty standard, UserUserGroup is a linking object with corresponding IDs. I am using Linq-to-SQL so unforunately it doesn't used nested objects, but it still knows the relation.
How do I find a specific node? In this case I want to find the node that has its name attribute to be "admin"
Dim authGroup As XElement = XElement.Parse(myXMLDoc.OuterXml) Dim foundUser As IEnumerable(Of XElement) = From i In authGroup.Elements Where i.Attributes("name") = "admin" Select i
I have been looking into dynamic querying of datasets and the use of copytodatatable() for a project. I have seen in alot of forums that the copytodatatable functionality is unusable as it was removed. have an example of a dynamic Linq query being loaded into a datatable.
I am trying to query from search box using list of data and the linq I used is:data = (From k As BSPLib.ContactLib.Contact In data_org.Values Where k.stringdata Like "%" & Searchtxtbox.Text & "%" Select k.prime).ToListBut this is not working, I am getting no data at all. Data_org is a dictionary so I used the values; k.stringdata contains all the data that need to be searched. Searchtxtbox.text contains the user defined search item.I Tried with sqlmethods through linq, but sqlmethods does not exist for me, I tried with with Imported namespace yet the code is not showing sql methods, could you please provide a workable query or just tell me where I have gone wron
When I try to query an entity that has a varbinary field in it I am getting error:"The LINQ expression node type 'ArrayIndex' is not supported in LINQ to Entities."
Here is my query:
Dim query = From entity In db.Entity Where entity.Id= Id Select entity.VarBinaryField
[code]....
The error gets generated when I check that the query isNot nothing.
"Create a class called Invoice that a hardware store might use to represent an invoice for an item sold at the store. An Invoice should include four pieces of information as instance variables--a part number (type String), a part description (type String), a quantity of the item being purchased (type Integer) and a price per item (Type Integer). Your class should have a constructor that initialize for each of the four instance variables. Provide a property for each instance variable. If the quantity is not positive it should be set to zero. If the price per item is not positive it should be set to zero."
I attached the code I have. obj is underlined and says "Argument not specified for parameter 'Invoice4' of the 'Public Sub New (Invoice1 As Object, Invoice2 As Object, Invoice3 As Object, Invoice4 As Object)' and so the program won't run. What am I doing wrong?
Public Class Form1
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Dim obj1 As New Invoice(Val(TextBox1.Text)) TextBox1.Text &= obj1.Invoice1 & vbNewLine TextBox1.Text &= obj1.Invoice2 & vbNewLine TextBox1.Text &= obj1.Invoice3 & vbNewLine TextBox1.Text &= obj1.Invoice4 & vbNewLine
I've come up with the following and it's partly working.
Public serial1, serial2, serial3, serial4, serial5 As SerialPort Public serialports() As Object = New Object() {serial1, serial2, serial3, serial4, serial5} dComPort = "COM4"[code]....
The above code works fine! But im having trouble trying to now retreive whats stored in the array.In the above example, an entry will be stored in serialports(4), all other array elements will be blank.If I do this it works.
MsgBox(serialports(4).PortName) ' this retuns the value COM4
But I'd like to loop though all array elements and print out ALL the PortNames, The below code doesnt work, I get an error Object variable or With block variable not set.
For i = 0 To serialports.Length - 1 MsgBox(serialports(i).portname) Next
how do i make the invoice number increase as i make each new invoice. i want to save each invoice then as i make the next one i want the number to increase,then be able to save that one and so on...
Elementos = From b In Elementos Where b.Value.IdGrupo = 0 Select b
"Elementos" is a dictionary(of long, MyObject). MyObject has approximately 50 properties.
The problem I have is that I have a new requirement to accept string parameter with a "where" condition. Something like "property1>10 and property2 like 'anystring' or property3<=25". (That means any property could have a condition. I have string and numeric properties.)
I'd like to keep using linq, adding the condition as it comes. I'm aware that it could produce an exception if the condition is misspelled or something, but that's acceptable (by try catchs). I wouldn't want to parse the string to build parameters or anything.
I am creating a tool that interfaces with an API for a CD/DVD burner. I have created several custom classes that will hold the information for the disk sets (which consist of a data path and a label file among other information. The DiskSet class has a list of Include objects. My proposed XML output would be something similar to the following:
<DiskSets> <DiskSet> <Name>MySet 1</Name>
[code].....
I am attempting to traverse the Includes collection (I have tried List and Binding List as I am also using this in a pair of datagridview controls) and it keeps returning Expression of type 'Object is not queryable. Make sure you are not missing an assembly reference and/or namespace import for the LINQ provider." How can I use LINQ to pull a list of the Include objects under each DiskSet object for transformation into XML? I am hoping to keep this restricted to this one block of code if possible.
I have a nested class, let's call it class1 and it has class2 inside it; VB.Net eg:[code]
1) How can I define X number of Class2 objects[let's call it: Node(x) array]** with NEW() subroutine called?' this raises error: dim cls2(n) as new class2 end sub.
2) How can I return actual number of Node() array? [code]Outside my class in main project I define cls1 object:[code]Now an array of class2 is created inside cls1.
3) Now,How can I access All of them[node(x) array which is created inside cls1] with all properties and methods available?
I remember I wrote a ProcessManager class with this functionality in .net 2003, nearly 4 years age, I don't have the code now.
Private Sub MakeMeSomeXmlBeforeRyanGetsAngry() Dim db As New MyDBDataContext Dim customer = From c In db.Customers Select c
[code]....
I am attempting to serialize my linq collection of customers. But it keeps throwing
Type 'System.Data.Linq.DataQuery`1[MyDB.Customer]' cannot be serialized. Consider marking it with the DataContractAttribute attribute, and marking all of its members you want serialized with the DataMemberAttribute attribute. See the Microsoft .NET Framework documentation for other supported types. My issue is that I have already marked the dbml Serialization Mode to UniDirectional and when I check the dbml codebehind all of the DataContract()> and DataMember()> elements are there. I have tried adding various dataloadoptions and setting deferredloading to false, but no luck.
Im trying to use LINQ to query Objets. I'm doing the following:
Dim myList As Generic.List(Of MyItem) = (From ThisItem In LinqToSqlObject.Items _ Join Folder In LinqToSqlObject.Folders _ On Folder.Id Equals Item.Id _
[Code]....
This however will not return any item that has a ParentItemId of null. I am trying to do a left join so as to return all "Item" regardless of whether it has a parent or not. I am aware that this is feasible in C# by adding an "into X" on the join, and selecting from X.DefaultIfEmpty(), this however does not appear to work in VB.Net.
The above line gets an error because I can't union List(of AnnotativeNode) with List(of DecisionNode). Each list defined like List(of EndNode) or List(of StartNode), but each class inherits from the base type Node.Is there a possible way to union these to get a result of IEnumerable(of Node)?
This feels like a completely basic question, but, for the life of me, I can't seem to work out an elegant solution.
Basically, I am doing a LINQ query creating a new object from the query. In the new object, I want to generate a auto-incremented number to allow me to keep a selection order for later use (named Iter in my example).
Here is my current solution that does what I need:
Dim query2 = From x As DictionaryEntry In MasterCalendarInstance _ Order By x.Key _ Select New With {.CalendarId = x.Key, .Iter = 0}
[Code]....
Is there a way to do this within the context of the LINQ query (so that I don't have to loop the collection after the query)?
Is there any way to use a LINQ to XML to query an XML document like the one below to create new (anonymous or strongly typed) objects from the child elements of a descendant? Here is my XML document:
I have collections of 2 different types - let's call them Cars and Trucks. Both share base class Vehicle, which has property Passengers.I want to merge them into a single collection ordered by that property. E.g., merge Cars and Trucks and order by Passengers.
Basically I have the follwing:Dim ctx As New AdminCoreEntities Dim roles = (From r In ctx.Roles where r.Name.StartsWith("cust") Select r) 'list of System .Linq.IQueryable(Of AdminCoreModel.Role)
[code]...
The error i get when i run this is: Unable to cast object of type System.Data.Objects.ObjectQuery`1[AdminCoreModel.Role] to type AdminCoreModel.Role
Basically I have a many to many situation and I try to get all the Quicklinks objects queried by their roles and not quite sure why EF will cast to a single AdminCoreModel.Role when i.Roles is a collections of objects.
I have a list of objects, each with 2 relevant properties: "ID" and "Name". Lets call the list "lstOutcomes".I need to check the list for duplicates (meaning object1.ID = object2.ID, etc.) and set a flag (valid = false, or something) if there is at least one duplicate. Also, it would be nice to send a message to the user mentioning the "Name" of the object, when it fails.I am sure I will need to use the Group By operator to do this, but I am not used to doing that in LINQ, and the examples out there are just not helping me. This article seems to be close to what i need, but not quite and it's in C#.
Here is a starting stab at it... Dim duplist = _ (From o As objectType In lstOutcomes _
I am in the process of learning LINQ to Objects. I am querying an array of reference elements using LINQ. In the code below, which I have marked with asteriks and PROBLEM, I am having difficulty returning any values for and I suspect its because of the multiple Select arguments.
'Program name:Querying an Array of Invoice Objects 'Created/revised: 'Project description:To demonstrate the use of LINQ to query objects
