I want to extract large amounts of data from Excel, manipulate it and put it back. I have found the best way to do this is to extract the data from an Excel Range in to a large array, change the contents on the array and write it back to the Excel Range.I am now rewriting the application using VB.NET 2008/2010 and wish to take advantage of any new features.
Currently I have to loop through the contents of the array to find elements with certain values; also sorting large arrays is cumbersome. I am looking to use the new features, including LINQ to manipulate the data in my array.Does anybody have any advice on the easiest ways to filter / query, sort etc. data in a large array. Also what are the reasonable limits to the size of the array?
I have one large XML file from one of our vendor and I am trying to pars it using Linq but it looks some wrong logic I am using.
This is xml file: HTML <Psw xmlns="http://localhost"> <exid>20</exid> <Mes><Me> <doc><ps> <ghder> .....
The code I am trying: Dim doc As XDocument doc = XDocument.Load(TextBox1.Text) Dim qList = (From xe In doc.Descendants.Elements("ghder") _ Select New With { _ .mid = xe.Element("MId").Value, _ .cdate = xe.Element("cD").Value _ ' As well I need to get the value for pn child attribute }).FirstOrDefault MsgBox(qList.mid)
Error for DBNull ' Object reference not set to an instance of an object.
I've build a large program with many references. F.e.:
System.Data.DataSetExtensions System.Linq.Dynamic
I've to write a Dynamic Linq Expression: [URL]
In my case: Dim query As IEnumerable = ds.Sales.Where(strWhere)
But with System.Data.DataSetExtensions Where is misinterpreted. The compiler expects (Datarow, Integer, Boolean). If I delete System.Data.DataSetExtensions everything is ok with this expression, but I get many other errors, so I need this reference. What can I do that the Where is interpreted correctly?
how can i query 2 arrays simultaneously?for example:
dim string1() as string = {"a","b","c"} dim string2() as string = {"d","e","f"} dim string3() as string = ? 'linq query that selects all elements in string1 + all elements in string2
Can this be rewritten any better using LINQ? I'm a C#er trying to think in VB.NET for this current project. It's in an ASP.NET Web Forms .vb codebehind:
Public ReadOnly Property AllowedCategoryIds As Integer() Get Dim ids = New List(Of Integer)
I want to write a program to do Markov chain, but my states are quite large. First of all I calculate all the transition probabilities and revenues for all states(1381860 total states), and store in a multidimensional array. Public RevArr(0 To 9, 0 To 750, 0 To 282) As Long
After that the iteration of markov chain should use these as inputs to calculate the steady-state probabilities. But when I try to run the main code I got this error.Exception of type 'System.OutOfMemoryException' was thrown.
The following is the declaration of second array I add just another dimension for storing all the iterations, but I get this error. Dim stateprob(IT + 1, 0 To 9, 0 To 750, 0 To 282) As single
In VB6 I load a recordset containg all of the records (6 fields per record)in a table into an XArray and then manipulate the records in the array and then write them back to the original table. The array issorted by the first field (1 to maybe 8000 or more) I need to find records in the array by an ID field and then move them (because of some external criteria that happens many times) from say number 400 to number 375. Then all of the other records between 375 and 399 were renumbered up 1 to fill the gaps left by the move.
The XArray worked well as it could find and also move to a next record easily to facilitate the revisions to each record quickly. Everything is done in VB6 in code and nothing visual needs to be shown to the user until say 2000 of these external changes are complete. What is the best, most efficient way to do this in the .Net framework in VB2010. Datasets, Dataviews. tableadapters, arrays. enums ?
My assignment is to have a user enter in big integers using what i think is two parallel arrays. I got this far but now im stuck. I think i need to actually convert the text box input into an array but i do not know how to do that. I am all over the place in this project.
'Created/ Revised by: Jessica Falcetta 'Cap 204 Final Project: Big Integer Project 'Project Purpose: To calculate large integers through parallel arrays
I have a VB.net console app and I am opening a function in a dll written in fortran. I am passing 3 arrays through the function by reference. When they come back out the otherside they ahve all tunred to arrays of only one element And that element is 0.I read on the internet somewhere that when doing this kind of thing it is a good idea to only pass the first element of the array into the function.I tried changing my function declaration to accepting single elements rather than single dimensional arrays, and now the arrays are the same length before and after the function call, but they don't seem to be changing at all, so i'm not sure that this is working
the statement Dim state(49) As String and maintain a list of certain states. The list of states should always be in alphabetical order and occupy consecutive elements of the array. The buttons in the program should give the user the following options: (a) Take the state specified by the user in a text box and insert it into its proper position in the array. If the state is already in the array, so report. (b) Take the state specified by the user in a text box and delete it from the array. If the state is not in the array, so report. (c) Display the states in the array. "
Private Sub states_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load state(0) = "Alabama"
I was wondering if anyone knows a built in method ( LINQ say or a LAMBDA expression or other way ) that you can compare2 arrays - collections that would be valid for an equivalent 3rd array - collection which is a combination of the 1st two.
I have a listbox on my xaml form that I bound to a List(Of MyType) property. I populated this list like so:
Dim fields As List(Of CheckableFields) = New List(Of CheckableFields) Using context As ITIPEntities = New ITIPEntities() Try[code]....
Now I'm at the point where the user selects the fields they want included in a report and I need to iterate over the required fields. This is my linq query:
For Each checkedField In _requiredFields If checkedField.IsChecked Then If checkedField.FieldData IsNot Nothing AndAlso checkedField.FieldData.Trim IsNot String.Empty Then[code].....
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."
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) = _
The pattern I'm trying to avoid is checking if a string (normally a control's text value) is null/empty, and if it is, comparing it using Contains to a field in my data. Obviously the field isn't hard-coded into my extension, neither is the object type.What I've got works perfectly in Linq to Objects, but I get the generic run-time error "LINQ to Entities does not recognize the method 'System.String Invoke(GenericQueryHelper.Customer)' method, and this method cannot be translated into a store expression." when using an entity framework model.
Here's what I have:
<System.Runtime.CompilerServices.Extension()> Public Function CompareAndFilter(Of T)(source As System.Linq.IQueryable(Of T), expressionField As System.Linq.Expressions.Expression(Of System.Func(Of T, String)), compareTo As String)
[code]....
I want my usage to look something like this:
Dim results = repository.Customers.CompareAndFilter(Function(c) c.FirstName, searchText)
I do need to get this running against a SQL database really, as it is filtering results, so I don't want to be doing that in memory.
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.
How can I convert an object of type System.Data.Linq.DataQuery to System.Linq.IQueryable?I'm working with Visual Basic/Silverlight, and the source code of my query is as follows:
Public Function Get_Cli_Pag() As IQueryable(Of V_Cliente_Pagare) Dim Qry = From P In Me.Context.Pagares Join C In Me.Context.Codigos On C.Codigo
I just upgraded a project from VB 2008 to VB 2010. Before, the project did not use LINQ. I have started implementing it. So, I have updated the target framework from 2.0 to 3.5, and added a reference to System.Core, and imported the namespace System.LINQ to the entire project and also imported System.Data.LINQ into the form I'm working with (because it was not available in the list for Imported Namespaces in the references tab).
It's not throwing any errors now, but my IntelliSense is not working for LINQ stuff.
For example... I write this:
[CODE]....................
Then, if I type S. on the next line, the IntelliSense doesn't grab what it should for S (Only get Equals, GetHashCode, GetType, ReferenceEquals, and ToString, instead of the options I should get like Count, First, FirstOrDefault, etc...). If I Type S.First. then its the same thing, no IntelliSense that lists the available fields for S, just the standard options (Equals, GetHashCode, GetType, ReferenceEquals, and ToString). I should be seeing my column names in my table when I type S.FirstOrDefault.
So any ideas what is going on? When I type the code, for example, MessageBox.Show(S.FirstOrDefault.FirstName), it works perfectly. But it doesn't change the casing of the text (so it would read s.firstordefault.firstname) and no intellisense while doing it. But no errors. BTW - Everything works perfectly when creating a NEW VS 2010 application, it's just my projects upgraded from Visual Basic 2008 that have this issue.
Below you will find a code sample that I have dummied up to try and demonstrate the issue I am having. However, this is just a dummied up piece of code. The actual program has noting to do with STUDENTS or TEACHERS. Basically, the problem I'm having is trying to have a CLASS within another CLASS each of which contain ARRAYS that need to be dynamic in size. The sample has a CLASS called STUDENTS that can have in theory many students, the number of which are unknown to the CLASS. I need to be able to add STUDENTS to the ARRAY programmatically.
The CLASSROOM Class should also be an Array since each TEACHER will have MANY Students. There will be only 1 Teacher for a given classroom but the SCHOOL will have MANY CLASSROOMS. Again, I need to programmatically add Teachers and Students without having predefined Array sizes. The code I have listed below will NOT work but it demonstrates what I am trying to achieve. I want to be able to reference the CLASS by using something like this ...
I feel like I should be able to use ARRAYLIST in both classes but haven't been able to get it to work. I've tried DIM'ing as ARRAY and can't get that to work either.If I can get ARRAYLIST to work then I shouldn't need to worry about expanding the array via UBOUND (if it's even possible).The REAL question is "How do I have a CLASS within a CLASS, each of which has ARRAYS that need to be dynamic in nature so they can be expanded as needed? The size of the array cannot be determined ahead of time".
REMEMBER . . . the actual program has nothing to do with Students and Teachers. This was just my way of demonstrating the issue using an analogy that I thought everyone could understand. The actual Class is much more involved.I have purposely hardcoded some values just to make the sample easier to work with. This is NOT how I normally program but is just here to hopefully make things a little more clear.
Here is the sample code . . . '*********************************************************************************** '*********************************************************************************** '***********************************************************************************
'Here is the code that is in the form - This obviously doesn't work
Private Sub TeacherTestDemo() Dim iTeacherIndex As Byte Dim iStudentIndex As Byte
Exact duplicate: How to switch a large app from VB6 to VB.Net Exact duplicate: Best strategy for moving applications from VB6 to VB.Net Exact duplicate: Conversion tool comparisons for VB6 tool which converts vb6 to vb.net
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.
So I am making a file crypter so that I can encrypt my VB.NET Application that I am making so that people can't decompile it. I had made this in C# and am transfering it to VB.NET, Everything worked fine in C# but once I had re-written the code in VB.NET i get this error inside of my RC4 Encryption method:
'Arithmetic operation resulted in an overflow.'
The error is occuring here:
Dim t As Int64 = (s(i) + s(j)) Mod 256
This is the same code above in c#:
int t = (s[i] + s[j]) % 256;
Is there anyway to make that calculation with it erroring? And why does it work in C# but not VB.NET?
provide Vb6 sample code to conert this value 2450258259404013568 to Hex as &h220110E7A7BE4000. while trying from win calc it's returning correct value as required.
How do you recommend I copy large files over the LAN (>20GB)Currently I am using File.Copy.Another question I have is how can I implement this class to be self contained, meaning that it would report progress to the object that called it? or do I have to define a delegate in the calling object?
Code: Public Class cCopier Private Delegate Function CopyProgressRoutine(ByVal totalFileSize As Int64, ByVal totalBytesTransferred As Int64, ByVal streamSize As Int64, ByVal streamBytesTransferred As Int64, ByVal dwStreamNumber As Int32, ByVal dwCallbackReason As Int32, ByVal hSourceFile As Int32, ByVal hDestinationFile As Int32, ByVal lpData As Int32) As Int32
