I am trying to get the DataView from a linq query expression which is querying a typed dataset. The result lands in a type of System.linq.IOrderedEnumerable. But i'm not able to convert this type to a Dataview although a few examples on the internet say that AsDataView function shoudl work but could you please throw some light on why the method AsDataView is not exposed on the query.
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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
[code]....
i have bounded my listbox to a dataset the result is system.data.dataview not name of all my students. below is my code.
con = New OleDbConnection("PROVIDER=microsoft.jet.oledb.4.0;data source=d:
redata.mdb")
con.Open()
[code].....
im trying to select some rows based on a criteria, i was wondering is it faster if i create a dataview (based on the criteria) and then loop through the view? or should i loop through the entire datatable and check the criteria manually.
View 5 RepliesIf want to do a DataView.Find on a DataTable that is already 'ORDERED' by the Column I am seaching, so a DataView.SORT should not be necessary, but it throws an Exception if I don't give a .sort command before the .find command. Is there any way to avoid this apparant duplication ? and speed up the search time. Its a very large table - 1 million rows. I am using VB 2010
View 6 RepliesI got a problem with dataview that get data from datatabel (Col1 : ID,Col2: Time) and I'm sorting by Time in desc ... when the values for example {40.21,80.21,70.25,25.2} the dataview sorting them as I need but when one of values goes above 100 for example {40.21,80.21,100.25,25.2} the dataview always sort the highest number is the buttom, I don't know why ..
This is a sample code
Dim dt As New DataTable
dt.Columns.Add("ID")
dt.Columns.Add("Time")
[CODE]...
I have a function (on vb.net) to get a data from a XMLWebService:
[Code]...
every time i run this code i get the same error
Unable to cast object of type 'System.Data.DataTable' to type 'System.Data.DataView'.
the code is
Dim plmExcelCon As New System.Data.OleDb.OleDbConnection
Dim cmdLoadExcel As System.Data.OleDb.OleDbDataAdapter
Dim PrmPathExcelFile As String
[Code]......
I'm in the process of teaching myself C# by converting an existing project and am stuck converting the following vb linq code:
Dim outStuff = From tt In (From t In Products.SelectMany(Function(p) If(p.tags IsNot Nothing, p.tags, New ObservableCollection(Of TagModel)))
Group By tagName = t.name,
v = (Aggregate p In Products Where If(p.tags IsNot Nothing, p.tags.Contains(t), Nothing) Into Sum(p.views)),
nl = (Aggregate p In Products Where If(p.tags IsNot Nothing, p.tags.Contains(t), Nothing) Into Sum(p.num_likes))
[Code]...
var x = Products.SelectMany(p => (p.tags != null) ? p.tags : new ObservableCollection<TagModel>());
var tags = from t in x group t by t.name into g select new { tagname=g.First().name};
I would use the System.Linq.Dynamic. I added the specified Dynamic.vb file, that starts like this:
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to my (VB.NET)solution. Now Visual Studio does not recognize anymore in the project files the System.XXX references, proposing me to change them to Global.System.XXX
I´m gettin the error Calling the fuction GetListItems but is kind weird because it works in Visual Studio 2008 Express but no in Visual Basic 2010 Express:
Dim ndQuery As XmlNode = xmlDoc.CreateNode(XmlNodeType.Element, "Query", "")
Dim ndViewFields As XmlNode = xmlDoc.CreateNode(XmlNodeType.Element, "ViewFields", "")
Dim ndQueryOptions As XmlNode = xmlDoc.CreateNode(XmlNodeType.Element,
[Code].....
What in this block of code would throw this exception?
'Get Highest Revision Number
If MyExtract_BTR.RevisionBlocks.Count > 1 Then
Try
[code].....
I'm converting the Linq query below from C# to VB.Net. Can you spot my error? The query joins 3 XML datasets. C# - This one works great.
List<Course> courses =
(from course in CourseXML.Descendants(ns + "row")
join coursecategory in CourseCategoryXML.Descendants("Table") on (string)course.Attribute("code") equals (string)coursecategory.Element("DATA")
[code]....
I need help converting datatable to xml using Linq. I could do it with hardcoded column names as you can see in my code .. but i need it without hardcoding it ..Example datatable ..My linq query ..
Dim xmlDoc As New XDocument(
From row In dt.AsEnumerable()
From row In dt.AsEnumerable()[code]......
I'm having a little trouble converting some LINQ to VB.[code]Online code translators are not helping, and my unfamiliarly with VB LINQ is not very good.
View 2 RepliesI recently switched from VB to C# and have, for the most part, been able to make the transition without too much trouble. Currently I am working on converting a VB.Net program into C# and am having trouble with a couple of code blocks that include Linq.
This is one of the VB.Net lines of code that I am having trouble with:
I have tried to do the same thing in C# like this:
I am getting a compile error on the dt, which says Could not find an implementation of the query pattern for source type 'System.Data.DataTable'.'GroupBy' not found. VS also has issues with the whole into Emailers = group;
I have tried to get this right using examples from my search but have not been able to get it right.
I am getting following error whenever I want to use IIf function inside entity framework query.
LINQ to Entities does not recognize the method 'System.Object IIf(Boolean, System.Object, System.Object)' method, and this method cannot be translated into a store expression.
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) = _
[code]....
I have a function that works great in C# that I'm converting to VB.Net. I'm having an issue converting the result set to a generic list in VB.net.
The code:
Public Function GetCategories() As List(Of Category)
Dim xmlDoc As XDocument = XDocument.Load("http://my_xml_api_url.com")
Dim categories = (From category In xmlDoc.Descendants("Table") _
Select New Category()).ToList(Of Category)()
Return categories
End Function
The error occurs when convertng the result via .ToList(Of Category)() The error:
Public Function ToList() As System.Collections.Generic.List(Of TSource)' defined in 'System.Linq.Enumerable' is not generic (or has no free type parameters) and so cannot have type arguments.
Category is a simple object I've created, stored in the App_Code directory.
I have the necessary "Imports System.Collections.Generic" reference in the file so I don't see why I can't convert the result set to a generic list.
I'm having trouble getting my head around converting a traditional SQL aggregate query into a LINQ one. The basic data dump works like so:
Dim result =
(From i As Models.InvoiceDetail In Data.InvoiceDetails.GetAll
Join ih As Models.InvoiceHeader In Data.InvoiceHeaders.GetAll On i.InvoiceHeaderID Equals ih.ID
[CODE].....................
What I need to really be getting out is ih.Period (a value from 1 to 12) and a corresponding aggregate value for i.ExtendedValue. When I try to Group ih I get errors about i being out of scope/context.
Can anyone help me by translating this SQL Statement to Linq? [code]
View 1 RepliesI'm using Linq to Sql and have a stored proc that won't generate a class. The stored proc draws data from multiple tables into a flat file resultset. The amount of data returned must be as small as possible, the number of round trips to the Sql Server need to be limited, and the amount of server-side processing must be limited as this is for an ASP.NET MVC project. So, I'm trying to write a Linq to Sql Query however am struggling to both replicate and limit the data returned. Here's the stored proc that I'm trying to convert:
[Code]....
I was trying to finish up a VB.NET class library project when I tried to remove all unused references. I know for a fact that I'm not explicitly using any thing from the System.Xml and System.Xml.Linq assemblies yet the "Unused References..." button never flags them for removal.In fact I even tried "Unused References..." on a blank project and it still never flagged them.
View 1 RepliesI am getting a really bizarre error and it makes no sense at all.Basically I have a user entity which has a Password property. This property is of Type Binary, the server data type being Binary(512).I am reading this value in and converting it to a byte array. However whenever I run my code I am getting a completely unrelated error of Unable to cast object of type 'System.Guid' to type 'System.String'.This strikes me as very odd since I am not using a property or variable of type string or GUID anywhere in this procedure where it falls over.
The code is below:
Public Shared Function ValidateUser(ByVal username As String, ByVal password As String) As UserValidationMessage
Using db As New EntityMapDataContext
Dim u = From user In db.Users
Where user.Username = username
[code]....
i am learning vb. net for my IT class. i have been set the task of making a simple web browser. i have been able to insert a web browser window into the form and set the url in the properties tab in the editor. i have inserted a buton and a textbox and have written code so that when clicked the text in the textbox will be set as the url property. below is the code i have used
[Code]...
I noticed when you kill winlongon.exe, you get a BSOD and your computer crashes. I have also noticed that a number of antiviruses including Norton and Kaspersky make their processes access denied, even to administrators! Even if you use a tool like PSKill or Process Explorer, you still can't kill them. For anyone who wants to see this for themselves, get Kaspersky antivirus and then try killing AVP.EXE from any task killing utility. It doesn't work!
I'm making an application which will limit certain processes from running on my computer until a master password has been entered, where upon the access to these processes will be unlocked. I don't want the user to be able to kill the process, but I want them to be able to use other programs (including task manger, etc). I have thought of many solutions to this, including having another process which will restart my main process whenever it is not present, but this brings forth the problem of a user simultaneously killing and then deleting both of the processes, possibly with a tool like Unlocker. I have also thought about disabling task manager, CMD and taskkill, but then I fear my program will become more like a virus than a legitimate piece of software, and also other utilities can be used which will kill processes.
My problem is that I don't want to be too constraining to the user of my application so that they are not able to use every day applications, but I don't want my application to be easy to circumvent, and thus become pointless.
I was given a school project in which I have to make a program that converts numbers between binary,decimal,octal and hexadecimal systems. I have figured out how to make a function to convert binary number to decimal number [code]With this code,a user can enter a number that isn't binary,and program will calculate it. How can I make that program doesn't calculate those numbers or doesn't accept anything else than 0 or 1? This is needed for other cases like octal and hexadecimal system.
View 3 RepliesUsing the code
Dim dr As OleDbDataReader
Dim dbconn As New OleDbConnection
dbconn.ConnectionString =
"Provider=Microsoft.Jet.OLEDB.4.0;Data source=" & "C:MyData.mdb"
[code]....
I can extract
ColumnName = Item
ColumnSize = 80
DataType = System.String
But to write a Parameter I need to convert this to
UpDateCmd.Parameters.Add("Item", OleDbType.BSTR, 80).Value
Is there an easier way of converting DataType = System.String to OleDbType.BSTR than having to make a list with Select Case?Or is there a method to find OleDbType.BSTR rather than reading DataType = System.String?I also tried
SchemaTable = dbconn.GetOleDbSchemaTable(System.Data.OleDb.
OleDbSchemaGuid.Columns, New Object() {Nothing, Nothing, "Auction"})
Dim RowCount As Int32
[code]....
But that also returns DataType = System.String.
Private Sub UpdatePictureBox()
pbShowImage.Image = lbAddImage.Text
End Sub
what should it be?
I'm saving the font of a label to a text file, and when I open the text file with my program, I want the label to have the same font that is listed within the text file. Now, the only problem I am having is that when I try to write the code for opening the text file, I can't set the font property of the label to a string. Label1.Font=[Font: Name=Microsoft Sans Serif, Size=9.75, Units=3, GdiCharSet=0, GdiVerticalFont= False]Here is what the code to open the text file and set the font of the label looks like:[code]The problem for the code happens at line 6. The error is: "Value of type 'String' cannot be converted to 'System.Drawing.Font'"ing each part of the font in the text file(i.e. Writing Font.Name and Font.Size properties in separate lines and then setting the label's font properties to each line accordingly), but I still get hit with the same error.
View 12 Replies