Creating A Sort Expressions For Datatable?
Feb 2, 2010
I have got a datatable which contains many columns in which three are main:
hotelid
dshotelid
hotelname
Some hotels contain only dshotelid, some contains only hotelid and some contain both dshotelid and hotelid.
I need sort in such way so that those hotels who got both dshotelid and hotelid should be on top and then those hotels who have got only dshotelid and at last those hotels who have got only hotelid...
create such a sort expression.
I created this :
dtmaintable.DefaultView.Sort = "dshotelid, hotelid"
but it Is not giving me desired output.
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Feb 17, 2011
I'm using vb.net 2010.I have a DataSet with a Table and data. MyDataSet1 which contains Table1 I want to create another table that is the same as the Table1 but without data, but it should have the columns, etc.
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Jun 22, 2010
I'm trying to sort a DataTable using the following code:
Private Function sortDataTable(ByVal dTable As DataTable) As DataTable
Dim dView As New DataView(dTable)
dView.Sort = "Field ASC"
Return dTable
End Function
But it doesn't work. What is wrong? How can I sort the DataTable?
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Jul 22, 2010
I was asked this question recently in a test, which I didn't pass. For the life of me, I couldn't spot what the problem was. It's probably something really obvious as well, but even a colleague of mine couldn't spot it either. The best I could come up with was issues with bottlenecks and naming inconsistencies of parameters! I blame it on the fact I've not done any vb.net for years, I've been doing C# mostly these days
[Code]...
The question: This function, although it will successfully sort a datatable, has a major problem with it.What is the problem? Re-write the function in either C# or VB.Net using LINQ.
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Sep 1, 2011
I currently have a datagridview that is built from a datatable So lets say we have 6 columns
A B C D E G
So the users will select there data from another program and paste into the the table. So lets assume that the data that is pasted is; (the column names are automatically put in)
A B C D E G
123 456 789 101 112 134
So the table will now look like following (I remove the first row because its the same as the column name)
A B C D E G
A B C D E G
123 456 789 101 112 134
My problem is that the users can rearrange thier tables(column index) so lets say user A has the table in this format
A B D E C G
123 456 101 112 789 134
So when they paste into the program, it will look like
A B C D E G
A B D E C G
123 456 101 112 789 134
So now "C" "D" "E" are incorrect and i need to swap those columns to be the same as the column name. I'm not sure how to attack this problem.My thoughts were to paste the data as is, than see what the first row in each column equals.so if it equals "A" assign it an index 0
B 1
C 2
This seems theres too many steps and will slow down the app...
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May 7, 2010
I have a piece of code that filters a datatable based upon the cumilative value of records in a particular field. In short i specify a number and the filter counts through the records (rows) in the datatable and select the records that together are either exactly equal to or do not exceed a specified value (defined in a combo box on a form).[code]...
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Apr 3, 2009
I have some comboboxes that are binded to some fields in a datatable
is it possible to sort each single combobox without soting the datatable?
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Jun 5, 2011
how to create ascending order datatable in asp.net without sorting method
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Mar 23, 2012
I need to sort a datatable. I do it with linq this an example
Dim query = From c In dt.AsEnumerable _
Order By c.Field(Of DateTime?)("LastPurchaseDate"), _
c.Field(Of String)("LastName") Descending
Dim dv As DataView = query.AsDataView
But my problem is that i need to sort the fields not by passing the name of the column but the index of that.
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Dec 10, 2010
I want to sort my datatable column(0) alphabetically, but cant seem to find a way to do it. Just to give you an idea:
[Code]...
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Feb 21, 2011
I am creating a datatable and then adding a column to it which is filled with data from existing column and parsed into correct format DateSold is my existing column from my datafile and I create NewDateSold by adding the column to the existing table and then parsing the information in date format.
This is added to a binding source which then is used to populate a combobox I want to be able to sort the combo box by NewDateSold Desc I was able to this on the original column by simply using the "order By" in my query, it seems now that I added new column it is no longer sorted? I am finding different solution such as using dataview and wish to know the best way to do this
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Dec 1, 2011
First off a great piece of code [URL] you saved me soooo much time. I am a somewhat newbee to VB2010 and was wondering how would i go about setting lets say setting column(4) to a date format so that i can get it to sort in the correct order.
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May 21, 2011
I am trying to go through a datatable and sort records that fall within a certain criteria, one being distance.I have a function that will get the distance between two points based on Lon/Lat and my records in table have Lon/Lat Values
exisitng code
Dim dtrow As DataRow
Dim lat As Double = CDbl(34.213209)
Dim lon As Double = CDbl(-118.629276)
[code]....
I can I now use the function to filter records in table that are with a certain distance?
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Aug 2, 2010
I have a page which lists all the files in a particular folder (all PDFs), using a data-table and gridview. I'm currently sorting this table by the filename (by using a dataview), which isn't that helpful, and I want the gridview of files sorted by the file created or file modified date (as recorded in Windows). If that's not possible, a second option would be to extract the date from the file name string (no problem doing that), and sort the dataview/datatable or gridview based on that.
[Code]...
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Apr 11, 2011
I have the following function so far and I dont know how to continue
Public Function getdetails(ByVal id as Integer) as Data.DataTable
Dim query as string
Dim mydatatable as Data.DataTable = new Data.DataTable()
[code]....
basically I am using to C# and just learning vn.net..What I want to do is save the information t,id and t.color in a datatable in vb.net..How do i do that.
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Jul 19, 2011
When I create a form using only one table in a database this works fine. However when I create a form that uses at least two tables I am getting an error on my ReceiptsAdapter (or my SQLDataAdapter). It's saying that I am using the incorrect syntax and need the keyword "From." I am assuming that I am getting this error because I am using multiple tables in my SQLCommand statement.
Imports System.Data
Imports System.Data.SqlClient
Public Class Receipts
[Code].....
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Jul 18, 2010
I'm wanting to have some datatables that are just used temporarily, mainly for creating and listing friendly versions of data that will be easier for the user to read in drop-down combos etc.
I would like them to be strongly typed to pick-up bugs at design-time. However I'm struggling to know how to achieve this. Do I need to create a custom class and inherit from DataTable and build the columns in the class constructor?I don't need a Dataset, just a DataTable?
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Feb 20, 2012
I have following code and it's slow to load first time. CSV file is about 4mb 16000 rows.
If Session("tb") Is Nothing Then
Dim str As String()
If (IsNothing(Cache("csvdata"))) Then
[Code].....
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May 5, 2010
I want to modify this function to populate an array with each item in the database.
I have tried various options, but I just can't get it to work[code]...
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Nov 20, 2010
If 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
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Apr 26, 2012
I have a array based on a structure that I want to build a datatable from. Here is what my structure looks like currently,
Public Structure QRQFiles
Public Complex As String
Public DescriptiveName As String[code]....
Since I have a structure with in the structure will I have to define two datatables to represent this?
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Dec 15, 2011
I have connected my sql db with vb and I m trying to make a UI. My question is that when I write code in order to create datatables and I fill them with the results of queries I've created, where do these datatables belong? I'm wondering if I have to define a new dataset or do they belong to the existed dataset which is created by the dataset configuration wizard??
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Jul 9, 2010
I have a datatable which has a number of rows containing dataThen I need to add some empty datacolumns which I do like this:
Code:
Dim OT_Hours As New DataColumn("OT_Hours")
OT_Hours.DataType = System.Type.GetType("System.Double")
[code].....
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Mar 22, 2009
I am working on a winform project like to dynamically create chexboxes from a datatable rows.
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Apr 11, 2008
I want to modify this function to populate an array with each item in the database.I have tried various options, but I just can't get it to work
Private Function ConnectMe() As DataTable
Dim conn As String = "Server=192.168.0.36;Port=3306;Database=wswc;Uid=r oot;Pwd=Jack"
Dim cmd As String = "SELECT * FROM st_users"
[code]....
Instead of fill, I want to one by one add it to the dataset and also an array?
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Dec 15, 2010
How can I improve this bit below to make the items in the TreeView to sort faster or something totally different to sort them easier?
[Code]...
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Jul 5, 2011
I have a MyObject; myObjects as List(Of MyObject) and a delegate Comparison(Of MyObject) that uses a lot of comparison functions (ByA, ByB, ByC etc) Ã la:
Shared Function CompareMyObjectsByName(x As MyObject, y As MyObject) As Integer
Return x.Name.CompareTo(y.Name)
End Function
[Code].....
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Jan 29, 2009
Sub Sort()
ReDim RollsCC(NumOfPlayers - 1)
For N As Integer = 0 To (NumOfPlayers - 1)[code]....
Here I am creating a temp single dimensional array, merging my 2d array into it, and then attempting to sort it by Rolls(N,1), which is a integer 1-6, Everything seems to be working right with the exception of this.
RollsCC.Sort(RollsCC, 0, 1)
How would one specify a numeral sort based on the first character in the string? im aware that I am switching Rolls(n,1) and Rolls(n,0) information during the sort.
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Apr 12, 2012
Currently my ListView sorts items by image.index. So 0 is at the top, then 1, 2 and so on. Think of it as an IRC chat room nick list. Ops at top then the rest are sorted alphabetically
[Code]....
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Nov 11, 2009
I see lambda expressions have become a very useful tool at some points in the language. I've been using them a lot and most of the time they fit really nice and make the code shorter and perhaps clearer.
Now.. I've seen some , I would say excessive use of them. Some people like them so much that try to use them everywhere they can.. Some times the C# code looks like a functional language. Other factors against are the cost using reflection by lambda and that not friendly to debugging.I would like to hear opinions about how good and how code clear it is to use more or less the lambda expressions. (this is not the better example, but let's say it was the trigger)I was writing the following code. The use of the delegate { return null; } helps me avoid having to ask if the event is null or not every time I have to use it.
public delegate ContactCellInfo.Guest AddGuest();
public event AddGuest GuestRequest = delegate { return null;}
Im using resharper and the wise resharper( even it some times literaly eats the memory) made me the following suggestion
public delegate ContactCellInfo.Guest AddGuest();
public event AddGuest GuestRequest = () => null;
At my point of view the code using the delegate looks clearer. I am not against the Lamdba expression just would like to hear some advices on how and when to use them.
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