How to declare Anonymous types. I want to do a different query based on a condition.
Something like this:
If true then
Dim Myquery = From data In MyXML.Root.<hist> _
Select New With { _
.SensorID = CType(data.<sensor>(0), Integer)}
else
[CODE]...
Then I want to reference MyQuery outside of the condition. But how do I declare MyQuery outside of the if statement?
Every LINQ example I have seen for VB.NET anonymous types claims I can do something like this:
[code]...
Now when I go to iterate through the collection(see example below), I get an error that says "Name "x" is not declared. For Each x in Infos It's like VB.NET doesn't understand that Infos is a collection of anonymous types created by LINQ and wants me to declare "x" as some type. (Wouldn't this defeat the purpose of an anonymous type?) I have added the references to System.Data.Linq and System.Data.DataSetExtensions to my project. Here is what I am importing with the class:
[code]...
Are anonymous types slower than declarative types?
For example, does
Dim score as Double = CalculateScore()
run slower than
Dim score = CalculateScore()
Why use explicit typing if it's no slower?
Assuming Anonymous Types are tailored to be used with LINQ, I'd like to use them for simply and fast data aggregation without an explicit class definition, like in this snippet[code]....
View 2 RepliesI have a problem using linq and anonymous types in an asp.net vb.net application.When I write the code above, I have 2 errors :
- "declarations of variable with Option Strinct On requires an As clause"
- "the name 'item' is not declared"
Public Sub MyFunc(ByVal xe As System.Xml.Linq.XElement)
Dim lstitems = From it In xe.Elements Select txt = it.@Text, value = it.@Value
For Each item In lstitems
Dim s As String = item.txt
Next
End Sub
Does it mean that is not possible to use Option Strict On and Option Explicit On ?Or I make a syntax error ?Or is it just a bad configuration of my application ?
I would like to use reflection on an anonymous type resulting from a LINQ to SQL query. I know that reflection on anonymous types works in general. The following code successfully generates a propertyinfo array with two elements:
Dim MyObject = New With {.Col1 = 1, .Col2 = "Test"}
Dim t As Type = MyObject.GetType()
Dim pilist As PropertyInfo() = t.GetProperties
[Code].....
Supposing the referenced List below contains 2 elements:
Dim Countries = From c In List _
Select New With { .Country = c.Country, .CountryID = c.CountryID }
The code above returns
.Country=Spain .CountryID = 1
.Country=Spain .CountryID = 1
How can I get the distinct values? The Countries query should contain only
.Country=Spain .CountryID = 1
Instinctively, I would say that this is impossible, as NHibernate needs to know some mapping information on how to persist a given type. Thus, I encountered some situations in which I could use such a feature. For instance, through a named query or something like so. On the other hand, using a named query would require me to make an addition to the configuration file.
Let's suppose we have an application interacting with some underlying datastore. This datastore is configured through the NHibernate configuration file. Then, I wish to have NHibernate load only a subset of an entity properties, from another subsystem to which my application shouldn't need to interact much, so it is not worthy to define classes for this system, as I only need a fraction of this alien system's information, let's say three out of thirty-two data columns. For that matter, if I chose to load only those three columns let's say for performance concerns, I would then use an anonymous type, perform the required action onto this information, then persist it back to the datastore. Now, it wouldn't be of much interest to do so if I only had one entity to get loaded from the datastore, so let's say I have about 75,000 rows to load into my process. I then shall consider this subset option very seriously!
What strategy should you choose in such situation, if you needed to persist these changes to a subset only of this entity's properties?FYI: I am asking because I must write specific rules of usage with NHibernate, such rules that even a beginner developer would even be able to use it without knowing too much about NHibernate, but only following the rules and guidance of the technical documents I have to produce.
Any best approach to what I'm trying to achieve (linq to sql, returning list of data to show in a grid/list etc etc)... Its complaining about anonymous type conversion, and from what I'm reading, thats not elegant way of doing it.
Public Function GetHistory(ByVal historyId As Integer) As List(Of ?????????)
Using dc As New myDataContext(Application.GetConnection)
Return (From t In dc.ActionTypes, a In t.MyTable Where a.HistoryID = historyId Select a.ActionOn, a.ActionBy, t.Description, a.ImpactedItem, a.ActionDescription).ToList
End Using
End Function
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
[Code].....
I was toying around with some of the linq samples that come with LINQPad. In the "C# 3.0 in a Nutshell" folder, under Chater 9 - Grouping, there is a sample query called "Grouping by Multiple Keys". It contains the following query:
from n in new[] { "Tom", "Dick", "Harry", "Mary", "Jay" }.AsQueryable()
group n by new
{
[Code].....
I've got the below, where I'm grouping a collection by a propery, then wanting to access the properties of my group. Problem I have is with the anonymous typing. Because of option strict I have to give an explicit type but I can't work out what the type should be. The below doesn't compile because t.HeadAccountKey isn't a value (as t has a type of object). So either I need do some casting or my linq selector is wrong,
[Code]....
The documentation has an example about grouping on multiple properties[code]...
Is it possible to rewrite the original query to just return IEnumerable(Of CustomerRegionGroup), or do I have to use the anonymous type, and run a second query on the result of the first?
I'm trying to create a web site that users can log into and self serve their user information ie name, address etc. I've set up a SQL server DB with a couple of table holding the data and accessing those using Linq. I'm selecting specific data from my datacontext then trying to assign it to a label, ideally I want to assign the value to a class attribute so I can use the users details on multiple pages.
I've simplified the code (removing WHERE statement etc for the purposes of this question):
Using CurrentUserDataContext
As
New UserDataDataContext()
[Code].....
I'm trying to translate some C# LINQ code into VB.NET and am stuck on how to declare an anonymous type in VB.NET.[code]How do you translate C#'s new { ... } syntax into VB.NET?
View 2 RepliesI am working on a project where I have to import a DLL file into a VB project that was created a few years back. The DLL was created in C++, and looks like:
void CoordinateConversionService::convert( SourceOrTarget::Enum sourceDirection, SourceOrTarget::Enum targetDirection, CoordinateTuple* sourceCoordinates, Accuracy* sourceAccuracy, CoordinateTuple& targetCoordinates, Accuracy& targetAccuracy )
I am an intern at my job, and I haven't had to use this yet, so my understanding is extremely limited, along with my usage of VB (I'm a C++/C# guy). Here are a few questions:
1) Looking at Dllimport, it seems like the last part outside of the parameters is a return type. Example code from another site:
<DllImport("advapi32.dll")> _
Public Function GetUserName( _
ByVal lpBuffer As StringBuilder, _
ByRef nSize As Integer) As Boolean
Is "As Boolean" the return type? If so, I tried using "Sub" and it says "Keyword does not name a type." Hence why I looked into declare, because it seems I CAN return void/sub as a return type.
2) Trying to use the types "CoordinateTuple" and "Accuracy" give me problems, saying that they aren't defined. How do I get around this since I don't think I can really define them, and what about the fact that they're pointers?
I'm out of my depth populating a windows form from an XML linq query (see code further down in post). The listbox is populated as intended, when a value is selected (row) I would like to populate the remaining form controls. The linq query I believe has created a new datatype "Anonymous Types". The query is only local to the load form subroutine but I'm not sure how to make it global.
When I define the query simply as an object the code in the selectedValueChanged event can't execute due to late databinding. how I can initially load the listbox from linq xml query and then populate the other controls when the value changes? Am I right in thinking even though the listbox is multi-columns (property) you can ONLY ever reference a row and NOT a column? I'm new to LINQ and Anonymous Types and the more I read the more confused I seem to get. On a less important note the order by is not functioning as intended (no errors) but data is always retrieved in xml file order and not by the node <text>. Also looked at using <text>.first to order the results without success.
[Code]...
I have the following statement, I want to turn it into a Public Shared Function :
If isEmployee Then
Dim employeeInstance As New Employee
employeeInstance = GetEmployeeInstanceByUserId(userId)
[Code]....
Public Shared Function GetWorkerInstance(Byval isEmployee as Boolean) As ...(not sure what to write here)...
There two possible return Type. I'm not sure what I should declare for the function return type.
Ok i'm trying to declare a global list of type T (or is it <anonymous type>) i declare it in a module with something like Friend query As New List(of {whatever type i try}) the app takes some xml and parses it into a list but i need this list available to other classes and methods within the app, everything i have tried fails resulting in an error like Value of type 'System.Collections.Generic.List(Of <anonymous type>)' cannot be converted to 'System.Collections.Generic.List(Of {whatever type i try})'.
What would be the correct way to declare a list of this type? is there another way i could do this?
I am using vb.net 2008 and sql 2008. How can I delete the last row of a record based on the condition that if the column. FileNo is more than 15 then it should get deleted order by Fdate column desc. I want the rows should get deleted from starting from the last row.
View 1 RepliesIn short I want a call a function jAlert() from jquery.alert.js file in a .aspx.vb page.. More details below
"When I click on "update page" the control goes to "ActionRepeaterItemBound" on code behind and then to my action.js page and this way I am able to add attributes and use them while calling my jscript function. However when I click on "Submit Update", the control first goes to action.js and then to "ProcessAction" on code behind. So I am not sure how I need to add attributes before the control goes into action.js."
I have a file jquery.alert.js which have functions like jAlert().
I have a file .aspx with part of code as below
[Code].....
My aspx.vb page has a function as below where attributes are added to control and are used in a page action.js to call the jAlert function
Protected Sub ActionRepeaterItemBound(ByVal Sender As Object, ByVal e As RepeaterItemEventArgs)
I want a similar logic to be performed on my LinkButton "CurrentActionCommit". How can I do this?
write a macro that removes the letters "TBD" from any cell it is in in a range of cells (J5:PJ421)n a different worksheet. This is probably very simple, but I am new to VBA and can't figure it out.
View 1 RepliesI'm working with a DataGridView that I want to format based on the condition of whether or not a date has passed. For example: If the date in a cell is past the current date, that cell and its row are formatted with the forecolor red. My current code is below, and while it doesn't present me with any errors, it just plain doesn't do anything.
Private Sub dataGridView1_CellFormatting(ByVal sender As Object, ByVal e As DataGridViewCellFormattingEventArgs) Handles DataGridView1.CellFormatting
If Me.DataGridView1.Columns(e.ColumnIndex).Name = "Due Date" Then
[Code].....
Am a student n am currently working on my final year poject n am new to vb.net. My project is for a clearing n forwarding agency. i need to prepare a bill for the duty to be paid. in a particular invoice, there may be single item r multiple item. for each item i've to calculate some values n display it on excel. i've made my excel book to be a template with all the things i should display. n the calculated values'll be displayed in corresponding cells which'll be retrived from database. if its single item its all good n i can prepare the bill easily but for multiple items i've to repeat certain cells from the template. i dunno hw to do it. am attaching my excel file with tis.i want to repeat the cells A24 to J35 'N' number of times with th
Dim xla As Excel.Application
Dim xlwb As Excel.Workbook
Dim xlws As Excel.Worksheet
[code].....
i want to create a system that will trigger alert based on few condition, my condition is:the alert will trigger if there is a negative value for 2 consecutive years.
example:
1)negative amount for 2005
2)negative amount for 2006
here is the code that i have for now and the result only can trigger alert for one year only..
[Code]...
I'm learning LINQ and VB and just spent an hour trying to access the fields of an anonymous type defined in a linq query. The key (I learned) is to convert the query to a list before you try to iterate through it with a for loop. How to access property of anonymous type in C#?
This does not work: edit (this compiles, but intellisense does not recognize the type)[code]...
So I'm writing a query as follows:
Dim assSummary = From a In db.Assignments
Join ur In db.UserRegions
On a.Origin.ID Equals ur.Region.ID
[code]....
In the controller I can return the data easily as follows:
For Each c In assSummary
MsgBox(c.Description & " " & c.AssCount)
Next
If I pass the object through to the view using Viewdata("assSummary") = assSummary, how do I display the data? Every method I've tried results in messages about 'VB$AnonymousType_7(Of Integer,String) and I don't know how to retrieve the data from the anonymous type.
I've a VB.net 2005 desktop application, and i'm using crystal reports. In one report i've abt 6-7 sub reports. is it possible to show/hide a sub report based on some condition. i'm new to crystal reports , please suggest what is the best possible way to achieve this.
View 1 Repliesi have 1 query with aggregate with condition using access
SELECT
HD.No,
SUM(IIf(DT.Status = 'A', 1, 0)) AS One,[code]...
i can run it in access but not in .Net QueryBuilder
Whats wrong with the below query, I am getting this error: Nullable object must have a value.
[Code]...