.net - Linq OrderBy On Duplicate Values?
Oct 20, 2011
m_ListOfsAllFields.OrderBy(Function(x) x.DisplayOrder)
here I have DisplayOrder = 0 for 2 fields, so orderby is messing up and not ordering properly. How can I use orderby to order this collection?
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Apr 4, 2012
The problem is: I have a list of objects, with some containing the same PlanId property value. I want to only grab the first occurrence of those and ignore the next object with that PlanId. The root problem is a View in the database, but it's tied in everywhere and I don't know if changing it will break a ton of stuff nearing a deadline.
So, if I have a list of PlanObjects like such.
Plan1.PlanId = 1
Plan2.PlanId = 1
Plan3.PlanId = 2
Plan4.PlanId = 3
Plan5.PlanId = 4
Plan6.PlanId = 4
I want to take a sub-list from that with LINQ (italics mean an item is not included)
Plan1.PlanId = 1
Plan2.PlanId = 1
Plan3.PlanId = 2
Plan4.PlanId = 3
Plan5.PlanId = 4
Plan6.PlanId = 4
For my needs, it doesn't matter which one is taken first. The Id is used to update a datsbase record.
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Jun 20, 2012
I'm having a problem implementing Scott G's Dynamic.vb extension at [URL] in my vb solution. I've searched StackOverflow (80+ Q&As) and numerous other sites without much luck. I'm using VS 2010.I've included Dynamic.vb in a problem with no root namespace, and then added a reference to that project in my main one. I'm getting intellisense for 4 overloads (rather than 2) so I'm pretty certain that the extension is in scope.I was having a tough time with clauses, especially the OrderBy as Scott demonstrated. If I simply pass a string as Scott's VB example did I get the error "Overload resolution failed because no accessible 'OrderBy' can be called with these arguments."
The line of code is:
Dim FilteredComponentList = From Component As MX.Component In ComponentList.AsQueryable _
.OrderBy("Name")
So I found other references that stated to pass a Lambda expression. So I tried this and at least I get no error, even if the sort function still doesn't seem to work. Here is the code that compiles and executes.
Private Sub SortByColumn()
If Not cmbComponentFilter.SelectedItem.ToString = "All" Then
Dim FilteredComponentList = From Component As MX.Component In ComponentList.AsQueryable _
[code]....
When I interrogate the dgvComponents.Columns(e.ColumnIndex).Name it gives the objects property I wish to sort by, but the sort still isn't working. I'm concerned why I can't get Scott's implementation to work, but I've heard his keynotes and read his blogs, so I'm guessing the problem lies with my implementation.
I'd like either to work but need to understand why as well. Why doesn't passing a string work? Isn't the PARAMARRAY declared in the function optional?
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Jan 24, 2010
I am trying to pass a lambda function to Linq's orderby and cannot get it to work.
The relevant code is:
Dim myordering = Function(m) m.Count
If isAlphaOrder Then
myOrdering = Function(m) m.Key 'Order by Alphabet
[Code].....
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May 11, 2012
I have a method in a webservice that has parameter with which users can decide how they want to order their results. This is a List(Of String) with the names of the fields in the order they want to sort them. I know I can normally order on multiple columns by doing the following
Dim test = Bars.OrderBy(Function(x) x.Foo) _
.ThenBy(Function(x) x.Bar) _
.ThenBy(Function(x) x.Test)
However in this case this won't work since I can't chain the ThenBy function because I'm adding the sorting orders in a loop. To use ThenBy I need an IOrderedQueryable collection. This is how I would want it to work
Dim sortColumns = {"Foo", "Bar", "Test"}
Dim query = From b in Bars
For each column in sortColumns
Select Case column
Case "Foo"
query = query.Orderby(Function(x) x.Foo)
[Code] .....
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Jul 5, 2011
Using the following DataTable:
Dim d As New DataTable()
d.Columns.Add("Product", GetType(System.String))
d.Columns.Add("Value", GetType(System.Double))
[code]....
I'm trying to use LINQ to identify if there are more than one of any type of product. In SQL, this would work something like:
SELECT Product FROM SOME_TABLE HAVING COUNT(*) > 1
I can't for the life of me work out how to do this in LINQ. I was following someone who did something like this:
Dim q = From row In d.AsEnumerable()
Group row By New { column1 = row("Product"), column2 = row("Value") }
Into grp
[code]....
But I get an error when I try to actually use 'q'. how I can make this work?
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Aug 9, 2009
I'm using VB .NET and I know that Union normally works ByRef but in VB, Strings are generally processed as if they were primitive datatypes.Consequently, here's the problem:
Sub Main()
Dim firstFile, secondFile As String(), resultingFile As New StringBuilder
firstFile = My.Computer.FileSystem.ReadAllText(My.Computer.FileSystem.SpecialDirectories.Desktop & "1.txt").Split(vbNewLine)
secondFile = My.Computer.FileSystem.ReadAllText(My.Computer.FileSystem.SpecialDirectories.Desktop & "2.txt").Split(vbNewLine)
[Code]...
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Feb 26, 2012
I'm using an unbound data grid in Visual Basic. I made the following loop for the purpose of searching each cell and each column for a duplicate value. But for some reason I get a "InvalidCastException" when I try to add a second row.
Private Sub AddJudgeBtn_Click(sender As System.Object, e As System.EventArgs) Handles AddJudgeBtn.Click
Dim exists As Boolean
' ToDo: If the value entered is already on the list, don't add again.
If JudgeList.Rows.Count() > 0 Then
[code]...
EDIT: Adding the entire click event.
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Dec 14, 2011
I am trying to get duplicate values from dgv into a combo:
[Code]...
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Jan 29, 2011
How can i avoid the duplicate values in the Access Database?? I am working in VB.NET, to create DataEntry Form. I have Combobox. When enter the value on Combobox and press OK button then the value should check on the database , if the value is not there then it should save on the db. else the Missage will give "It is Saved".
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Jun 21, 2010
I want to insert number for City_Id and City_name , i wrote a query for auto generate number for City_Id,working fine but in the city name i want to avoid inserting duplicate value like if Mumbai is a City ihave already saved then system should not allow that name again. neither in small or in capital or mixed letter.
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Aug 5, 2009
am new to VB.NET and i was wondering if anyone here knows how to check for duplicate values in strings?
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Dec 15, 2011
I need to validate a particular coloumn in datagrid for duplicate values before inserting into database. I am using datatable.
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Mar 9, 2010
Get Random value with no duplicate
[Code]...
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Jan 20, 2009
I have a fairly large Drop down menu:
<asp:DropDownList ID="DropDownList8" runat="server" AutoPostBack="True" OnSelectedIndexChanged="DropDownList8_SelectedIndexChanged">
<asp:ListItem Value="" Selected="True"></asp:ListItem>
[code]......
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Oct 27, 2010
I am creating an xml file with LINQ as follows...
Public Sub CreateXml()
Dim db As New MDataContext
Dim Customers = <gallery columns="3" rows="3">
[code]....
Could i mix local values with the ones returned from the LINQ query...Something like the following?
Public Sub CreateXml(ByVal **Col** As String, ByVal **Row** As String)
Dim db As New MDataContext
Dim Customers = <gallery columns="& **Col** &" rows="& **Row** &">
[code]...
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Nov 7, 2010
How can I avoid Duplicate values in Datagrideview. When I am putting Product Id in Invoice which is adding in datagrideview if it is exist in datagrideview it will Highlight with deferent color and give me massage that this Id is existent in datagrideview
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Apr 14, 2011
I have a form where two fields on the first page of the form make up the primary key. I want to check for duplicate values before attempting to insert the record, since I don't want the user to go all the way through the form only to find out they can't submit it. So I'm trying to check for duplicate values when the user tries to go to the next page of the form. I wasn't quite sure how to do it, and sure enough I'm getting an error. ("Object reference not set to an instance of an object.") The problem is apparently in my if statement, "If myValue.Length > 0 Then", but I'm not sure what needs to be in place of that.
Protected Sub CustomValidator1_ServerValidate(ByVal source As Object, ByVal args As System.Web.UI.WebControls.ServerValidateEventArgs) Handles CustomValidator1.ServerValidate
'get values
[code].....
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Jul 5, 2011
I am trying to create a .Net application to edit a excel file by deleting some columns and keeping the columns which we need and then removing the duplicate values based on the first column which is going to be the Serial no. which should have a check to have 6 digits by default like 2563 should be displayed as 002563.
Code:
Public Function GetAllFileContents(ByVal path As String, ByRef errorMessage As String) As IList(Of String)
Dim contents = New List(Of String)
Try
Dim files = Directory.GetFiles(path, "*.xls")
If (files.Length = 0) Then errorMessage = "Please select the files"
For Each file In files
[Code] .....
I am trying to create something different by not only letting me do it for excel files but for say txt and csv files along with it. Removing all the values which I dont want and removing the duplicates and then if possible putting a check on the first column of data that the serial number number should have minimum of 6 characters and then The output file should have all the details in Uppercase
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Feb 10, 2012
How do I prevent users from a inserting a duplicate value using SQL Query
datatype is VarChar(50)
e.g. the name field has already been defined as "Josh", I don't want it to be able to add another "Josh"
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Feb 4, 2011
I am sending values from Combobox and Textbox to Access Database in VB.NET.I am phasing the problem when i enter the Duplicate values.In the database one of the column is Indexed.(Yes Duplicates not allow)That column i bind to Textbox("txtperson1").I used the TRY and Catche method to solve the Indexed Problem.when i run the application the value which i enter is not a duplicate that value save on the db. Once i enter the Duplicate value , the message box is showing "The Record alread saved".But After i enter the new value the same message is displaying, it is not saving on the db.
[Code]...
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Jul 29, 2009
Here is my
cn = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=BHgardeners11.mdb;")
cn.Open()
Try
str = "UPDATE Products SET ProductCode = ?, ProductManufacturerCode = ?, ProductsTitle = ?,
[Code] .....
If there is only one item in the database, then this code works. If there is more than one record then the error is produced that it is trying to produce duplicate values. This is down to the Primary key in my database which is the only thing that cannot have duplicate values. However, when I remove the primary key it has the predictable problem that it goes crazy and does weird things.
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Apr 4, 2011
I had restart my program for 5 times, and i still can get through it. the due date just around the corner.
"The changes you requested to the table were not successful because they would create duplicate values in the index, primary key, or relationship. Change the data in the field or fields that contain duplicate data, remove the index, or redefine the index to permit duplicate entries and try again."
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May 26, 2009
I'm new to Linq, what's the syntax for orderby in VB? [code]Select distinct state from zipcodes order by State
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Jul 30, 2009
I am currently reading Pro LINQ c# 2008, and in page 87 the guy says OrderBy and OrderByDescending are stable. But he says exactly the opposite in page 96. It looks to me as he is referring to exactly the same functions, so I don't get it. Are they stable or not?
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Jun 7, 2012
I have a grid view with a lot of columns, all need to be sorted on. I have seen a few snippets out there, but I cannot get any of them to work with my example. Here is what I have so far.
Protected Sub gvSearch_OnSorting(ByVal sender As Object, _
ByVal e As GridViewSortEventArgs)
If Not Session("sort") Is Nothing Then
[code].....
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May 16, 2012
How do i read through a textfile line by line checking for and removing duplicate values?
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Jan 10, 2009
I'm using the datagridview. This is the sample data:
[Code]....
How do I parse through the grid to rename the duplicate values in a particular column (in this example it's the l_name field) into such a format?
[Code]....
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Jan 15, 2011
I am attempting inserting into an Access database, and the insert is successful (when I open the database the data is there), but I'm getting an error: "The changes you requested to the table were not successful because they would create duplicate values in the index, primary key, or relationship. Change the data in the field or fields that contain duplicate data, remove the index, or redefine the index to permit duplicate entries and try again."
This is really confusing me. No matter what I insert, it still gives me the same error. And I don't understand why it's giving me an error even though it's working. Here's my codebehind:
Protected Sub Wizard1_FinishButtonClick(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.WizardNavigationEventArgs) Handles Wizard1.FinishButtonClick
[Code]....
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Oct 1, 2009
I am attempting inserting into an Access database, and the insert is successful (when I open the database the data is there), but I'm getting an error: "The changes you requested to the table were not successful because they would create duplicate values in the index, primary key, or relationship. Change the data in the field or fields that contain duplicate data, remove the index, or redefine the index to permit duplicate entries and
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