I am trying to AVERAGE 6 different fields on a DataTable, but without grouping. Just the AVERAGE. I have found a couple of examples in C#, but can't find any examples for how to do this in VB.Here is what I have so far:
Dim query = From dtRow In dtIn.AsEnumerable _
Where dtRow.Field(Of String)("FOLLOWUP") = "Alert" _
Select New With { _
.Brand_Functional_Avg = XXX.Average(Function(f) f("Brand_Functional")), _
.Brand_Personal_Avg = XXX.Average(Function(f) f("Brand_Personal")) _
}
What should I use for XXX? I tried all of the options that I could think of and nothing is compiling.
Trust me, if I could write this in C#, I would, but the project requires VB.
I have a query that I cannot seem to replicate in expression method chain syntax. I have two tables "User" and "UserPayment". User and UserPayment have a one to many relation i.e. One User can have many UserPayments.
Dim qry As <??> = From f In dirInfo.GetFiles("*.QBW") Select File = f.FullName, Include = True Dim dt As DataTable = qry.CopyToDataTable()
I tried as "IEnumerable(Of DataRow)" but that didn't work. At runtime it said:
Unable to cast object of type 'WhereSelectArrayIterator2[System.IO.FileInfo,VB$AnonymousType_02[System.String,System.Boolean]]' to type 'System.Collections.Generic.IEnumerable`1[System.Data.DataRow]'.
I know that LINQ queries are deferred and only executed when the query is enumerated, but I'm having trouble figuring out exactly when that happens.Certainly in a For Each loop, the query would be enumerated.What's the rule of thumb to follow? I don't want to accidentally enumerate over my query twice if it's a huge result.
For example, does System.Linq.Enumerable.First enumerate over the whole query? I ask for performance reasons. I want to pass a LINQ result set to an ASP.NET MVC view, and I also want to pass the First element separately. Enumerating over the results twice would be painful.It would be great to turn on some kind of flag that alerts me each time a LINQ query is enumerated. That way I could catch scenarios when I accidentally enumerate twice.
I have 7 company Divisions that sit in an access database.I then use this list to populate two comboboxes in my windows form.However I get a syntax error in my SQL Query if the Division name is more than one word.For example in my access database I have two columns one is a status column and the other is a division column. If for example the Division is called 'Corporate' the status column is called 'Status Corporate' and the division column is called 'Corporate'.The SQL query works fine in this scenario.However if I have a Division that is more than one word, lets say 'Operations Division' I get an error in my SQL Query that says -
Quote: Syntax error (missing operator) in query expression 'Operations Division'.Here is my code
sqlNewTenderDetails = "SELECT " & Me.DivisionBox.SelectedValue & " From BidRefCodes Where " & "[Status " & Me.DivisionBox.SelectedValue & "='Active'" daNewTenderDetails = New OleDb.OleDbDataAdapter(sqlNewTenderDetails, NewTenderDetailsTableCon)[code]....
I have to join two main tables, and I need to filter the results by elements in an ASP.NET web form. These filters are created on the fly so I have to use a lot of where extensions to filter the query. I want to execute the query with as optimized SQL as possible.
I am first doing a simple join between TW_Sites and TW_Investigators. Then there are two sub-tables that are involved. TW_InvestigatorToArea and TW_InvestigatorToDisease. While most of the where clauses are working fine, I have found a performance issue that won't be an issue right now, but will be an issue as the table gets bigger.
The arrays DiseaseCategories and DiseaseAreas would be the results of a CheckBoxList result.
Protected Sub LoadResults() 'Get Dictionary of Filters Dim FilterDictionary As OrderedDictionary = Session.Item("InvestigatorFilterDictionary") ' Initialize LinqToSql
Forgive my ignorance on this.I have this LINQ Query:Dim ngBikersDataContext As New CarBikeWalkDataContext
bikersList = (From c In ngBikersDataContext.Reg_Bikers _ Order By c.L_Name _ Select New Bikers() With { _ .BikerID = c.BikerID, _ .F_Name = c.F_Name, _
[Code]...
with the error "Overload resolution failed because no accesible 'Select' accepts this number of arguments." Over the "NEW" I get an error " ')'expected."
After I have programmed several projects in VB.Net I to my surprise discovered that there are some more than subtle differences between C# and VB.NET LINQ usage.For example, if we want to group elements by multiple properties (columns) we need to create a new anonymous type explicitly:
var procs = from c in Process.GetProcesses() group c by new {c.BasePriority, c.Id} into d select d;
whereas in VB.NET more straightforward syntax will already do:
Dim b = From c In Process.GetProcesses() Group c By c.BasePriority, c.Id Into Group Select Group
So, one does not need to create a type with "new" here. What are the other differences? good comparison between the LINQ syntax in C# and VB.NET?
What I really want is to select these two tables in to an anon type like in Scott Gu's blog: here However, I would settle for this created type "ActiveLots" I am joining two tables together and want to be able to reference columns from each in my result set. [code]...
We are doing a query against an in-memory collection of LINQ data objects. The wrinkle is that we are ordering by a column in a related table whose records have not necessarily been loaded yet (deferred loading:)
Dim oPkgProducts = _ From b In oBillPkg.BillProducts _ Where b.Successful.GetValueOrDefault(Common.X_INDETERMINATE) = _
I'm a bit of a LINQ newbie and I was having some trouble with the following. I'm trying to perform a query using LINQ on an XML file and store the results in a list of DataClass objects that match the XML.I've got an XML file that is defined like this:
I have created a Data class to support this XML format. What I would like to do is create a LINQ Query to grab these 3 records and store them into a List of my DataClass. In order to support multiple Order elements, I have my class defined with a generic list of "Order" structs... It looks like this:
Public Class ASNData Private _field As String Private _value As String[code].....
how to grab the 3 order elements and store them into my list of Order structs.
This xml, when loaded in an XDocument, can be loaded and queried as follows:
Dim xdoc = XDocument.Load("sample.xml") Console.WriteLine(xml.Root.<Child>.@Name)
Then I change the <Root> element in the sample xml file to:
<Root xmlns="http://SomeNamespace">
Now I can't seem to use the convenient 'Axis Properties' syntax anymore... I can only get it to work with the explicit XElement syntax:
Dim ns As XNamespace = "http://SomeNamespace" ' works, but I would like to use the same syntax as above... Console.WriteLine(xdoc.Descendants(ns + "Child").First().Attribute("Name").Value)
How do I add ROW_NUMBER to a LINQ query or Entity? How can I convert this solution to VB.NET?
[Code]...
I'm having trouble porting that last line. I have been unable to locate a VB.NET example. I'm actually not looking for any paging functionality like the example provides, just good old-fashioned Row_Number(Order By X) row index.
I have a LINQ to sql statement that joins 2 tables. I would like to add a order by clause on one of the columns. However the order by clause does not seem to take effect at all. right syntax in VB.net to achieve order by in the following:
Dim query = From dtIt In dbsomecontext.mytable Join dtIl In dbsomecontext.anothertable On dtIt.ItemID Equals dtIl.ItemID Where dtIl.IsAvailable = True Order By dtIt.manufacturer
I was wandering is it possible to use a query within another query below is the code I am trying to use.
Public Function GetInventByComp(ByVal CompID As String) Using DC As New DataClassDataContext 'need to get company id's based off names? thats bad should be name from Id need to rethink this Dim invent = (From C In DC.Inventors_Companies _ Where C.CompID = CompID _ Select C.InventorID).ToString
[Code]...
I was trying to us multiple values in a string like "1, 3, 5" but I can't seem to get that working either so I am trying to use just a single value now. Can anyone help me? "Yes I am new to this"
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?
I am having problems implementing this query in vb.net.The error message that I am getting is with the "as" in the first line.This is a local sql compact database 3.5
cmd.CommandText = "UPDATE player as a " & "SET starter = 'TRUE' " & "WHERE NOT EXISTS (SELECT '1' " &
My code is supposed to select the month fand see what product ahas been sold and how much has been sold. It does it but i keep getting a Incorrect syntax near '='. and i cannot fix
