Working With An Instance Of A Dataset / Datatable From Other Classes
Apr 27, 2010vs2010 vb.net QUESTION1 If i do a select and fill a datatable and want to access that data from another class. How can I do that? QUESTION1 example
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Get The Instance Of One Datatable In DataSet By Tablename?
Aug 2, 2009this code:
If Not DataSet1.Tables.Contains("Table0") Then
DataSet1.Tables.Add(New DataTable("Table0"))
End If
[code].....
DataSet Editor - Allows The User To Edit A DataTable In A Strongly-typed DataSet
Mar 15, 2010When the user clicks an "Edit" button on my form, I want a box to come up which allows the user to edit a DataTable in a strongly-typed DataSet. What's the best way to do this?
View 2 RepliesIDE :: Dataset Code Behind Datatable.ColumnChanging Event Firing / But Dataset.HasChanges Property Not True
Jan 28, 2010I have code running in the Datatable.ColumnChanging event in my dataset. This dataset underlies a form and conventional drag/drop controls are in place for data entry.when the event triggers and runs, I am running code in the form that checks the dataset.HasChanges property. It is showing False. But this is immediately after the ColumnChanging event has been triggered.Okay, I see by others posts and MSDN that .HasChanges will only be true after moving off the row with the changed column. I have also noted lots of discussion about the advanced binding property of DataSourceUpdate Mode, but that does not address this issue.I guess I can do this by checking the state of the row for the binding source. Just seems odd that the event behind the dataset can be triggered and that does not change the dataset.HasChanges property.
View 3 RepliesCalling An Instance Of Nested Classes
Jul 14, 2011I`m a beginner in programming and i`m having problems calling an instance of my nested classes. I`m using VB.net and my code is something like this
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Asp.net - Copy Data From Datatable To Dataset.datatable?
Oct 31, 2010how to copy data from datatable to table in dataset i ry this but its readonly property
ds.datatable1=newdt.copy
Instance A Class, Based On Other Classes, Add New Properties?
May 26, 2009You know how everyone says "C++ is like C with classes"?How similar is it to .NET classes? instance a class, based on other classes, add new properties, override existing properties, etc?Are the variables strongly-typed and declared before they are used? Or is it a Duck-Typing language like Python?
Also, does it have its own Garbage Collector that disposes of objects when the pointer exits their scope,or do you have to manually clear and get rid of them when you finish with them? What's the difference between native C++, and the "managed C++" in Visual Studio? Because I'd prefer to use native code if its not too much harder. for the sake of all that is good and holy, don't use ACCESS, EXCEL, or a TEXT FILE as a database. If you want your program to use a "local database", without any of the hassle of setting up a MS SQL or MySQL server, just click this link: >>> SQLite <<< Seriously. This is for your own good.
VS 2008 Reference The Same Instance Of A Class From Different Classes?
Feb 2, 2010Whats the best way to instantiate a class so that i can have access to the object from diffreent forms and classes?
View 2 RepliesAccessing DataSet From Various Classes?
Feb 1, 2012For a little background, I am trying to make an application 'plug-in' based, more or less.Now, I have a business logic .dll, invoked by the main form, that will run and pull some data and spit out a dataset. I then have various other classes/.dlls that work of this dataset.
View 4 RepliesWorking With Custom Classes?
Dec 16, 2010I already know how to make really basic custom controls where I can pass in new variables to treenodes because of my custom class, but it's not really working out well for me.I figured out how to read the new values & change them while their in the normal treenode because oddly enough once i've passed in an object from my custom treenode class it worked but I want to know a few things.
1.With my custom class, I can't do things like the following.
MsgBox(
New
TreeNode("Today").IsSelected)
If I replace with CustomTreeNode it doesn't work no matter what I do even working with sub/new it always shows a default value instead of what value is, the most I can think of is because sub isn't returning value, but you can't return value in subs, how are you meant to make lines like that work?
2.Also anyways just for sake of having good intellisense & workings is there a way I can make a class of CustomTreeView that's using my CustomTreeNode's so that I can work on things by code in the EXACT same manor I used to given the name is the same but have my new custom values?Currently im stuck passing any changes using the new type & taking it out I type cast over to the custom type again so i can read the values, but I just want was wondering what I need to do to make it work like a real control would.
Anyways is there any way to over-ride the default control or something instead so I can simply add the new variables in there? I want the same functionality of the normal control just with the added variables so I can work with data pertaining to the nodes of each item in the treenode easier.I already used the Tag value to store some information but it's not like that there are 100 different variables to store information & it's not like anyone wants to store lots of values in 1 variable & parse out the one you need, it's possible but if I can create something good here, I want to use whatever I can make instead of taking my time on working on a more painfully difficult to work with, at least later when I might even need even more variables stored pertaining to each of the items.
Winforms Data Binding: Custom Classes Or Datatable?
Jul 8, 2009Am in the process of architecting a new windows forms application, and I intend to use Visual Basic 2008 and SQL Server Express 2005. This is my first application in .Net and I really want to observe the best OOD & OOP principles to create an application that is easy to maintain and extend (add new functionality). My issue is in regard to databinding on the UI. From experience, what do you guys recommend to use for databinding? Should I return datasets/datatables from my Business Layer and bind these to UI controls or should I return Business Objects and bind these to UI controls? And what are the pros and cons of each approach?
View 1 RepliesShare Dataset Between Classes In A Windows Service
Apr 20, 2012In all the Windows Forms Projects I've been able to share a dataset between the forms without a problem, so I assumed that it would be the same in a Windows Service. The issue I'm having is getting Class B to reference an existing dataset in Class that contains data. "Serv" is the class containing the dataset. When I say "Dim Serv1 as New Serv" and then declare my dataset/datatable references, the debug is showing that the dataset is empty, but I know the dataset contains data because I filled it in another sub procedure and checked that it contains data. How do I share a dataset between classes in a Windows Service?
View 2 RepliesWorking With Data Organized By Classes
May 30, 2009I am working in vb2008. How to store Class/Structure instance data into a database as single objects.
SomeClass
.name
.address
.age
.etc
Say I have a hundred instances of "SomeClass" stored with data. Is there a way that I can store each of my hundred instances as a hundred objects to a hundred Access database records. I am trying to avoid having to mirror my class structure into a datatable and treat each instance as a single object which can be stored into a single database column name.
Declare Main Class On FrmMain - Working With Classes?
Jun 3, 2009Currently I declare my main class on frmMain. as public MyClass as new clsMyClass Thus anywhere in the application I would address it as: frmMain.MyClass.Function(MyParam) This does not look as neat as I would like it. Where can I load this Class so that I can address it as: MyClass.Function(MyParam) from anywhere inside the application.
View 6 RepliesMultithreading Accessing A Dataset From Within A Threaded Class Instance?
Nov 1, 2011I was using the following code within a class and creating an instance of that class from within my main form (Main.vb):Dim count As Integer = Main.DbDataSet.Accounts.CountThis was returning the count of accounts within my database.After changing the code so that I could run this in a background thread to save locking up the program, as more data is processed after this point, the count was returning 0 each time.
View 1 RepliesAny Way To Add DataTable To DataSet?
Jul 29, 2010I have build a datatable in vb
dim Booking_table as datatable
Is it possible to add this datatable to a dataset or do I have to build in acces2007 and import in VB.
DataSet / DataTable - How To Do Add Row
Nov 4, 2010I have a strongly typed dataset and datatable and I am trying to do an add row.
Dim newDT As New hdar.AccessRequestsDataTable
Dim newRow As hdar.AccessRequestsRow = newDT.NewAccessRequestsRow
newRow.Number = nextNumber
newRow.RequestedByID = Me.cboUser.SelectedValue
newRow.RequestedOn = Date.Now.ToShortDateString
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Get ID From DataTable With Dataset?
Apr 27, 2012i am using Microsoft.Office.Interop.Excel to read the data from excel,
--Students_Table--
id_S | Name | Sex
12 john M
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-----the table where uploaded excel file saved--
id_u | id-S | Scor |
1 12 30
i want to get the Id_S from "John"(excel file), i tried using the dataset with query
select Id_P from Students_Table where (Name =: Name)
and then check fillBy & GetBy my vb code :
Dim ta As New Students_TableAdapters.StudentsTableAdapter
Dim DataID as Integer
if ta.fillBy(ExlRead.Value) <> 0 then
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i use breakpoint to check those and i found an error message
"ORA-01722: invalid number"
(i'm using oracle database)if i pointed my cursor to the ta.fillBy it shows Public Overridalle Overload Function FillBy(Name as string) as decimal?
Object Reference Not Set To An Instance Of An Object With A Class With An Array Of Classes As A Member?
Aug 6, 2010Here is the structure that I have:
Friend Class StandardFormatFile
Friend fileType As String
Friend numberOfSeries As Integer
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Dataset And Inside Of It Theres Two(2) Datatable?
Jul 27, 2010I have a dataset and inside of it theres two(2) datatable. Is it possible to do this kind of query.
"SELECT DATATABLE1.NAME FROM DATATABLE1 INNER JOIN DATATABLE2 ON DATATABLE1.ID = DATATABLE2.ID"
.net - DataTable Already Belongs To Another DataSet
Jan 12, 2012This error is occuring while adding one datatable from a dataset to another ."DataTable already belongs to another DataSet."
dsformulaValues.Tables.Add(m_DataAccess.GetFormulaValues(dv.ToTable.DefaultView.ToTable(False, strSelectedCols)).Tables(0))
Putting A Datatable Into A Dataset?
Jun 16, 2010I am trying to put a datatable into a dateset, which I then export to a CSV file. I am getting this error
DataTable already belongs to another DataSet. on the following line dsExport.Tables.Add(dtExport)
VB
Using dtExport As DataTable = DirectCast(dgvSafetyGlasses.DataSource, DataTable)
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Xmldocument To Datatable Or Dataset?
Mar 16, 2009I am ably to load a XML file (via a filepath) to a datatable. See code below.However, I'd like to be able to load a in-memory XML document to a datatable.
Code: Public Function XmlToDataTable(ByRef filePath As String) As DataTable
Dim ds As New DataSet Dim dt As New DataTable ds.ReadXml(filePath) dt = ds.Tables(0).Copy()
Return dt
End Function
.net - Automated DataSet/DataTable Instead Of SQLCommands?
Dec 26, 2011I used to do all the database logic with SqlCommand and the Methodes ExecuteReader and ExecuteNonReader and never used something like DataSet or Datatable.
Dim dbcon As Data.Common.DbConnection
Dim cmdselect = dbcon.CreateCommand()
cmdselect.CommandText = "SELECT * FROM users WHERE id = 1"[code]...
This is sometimes hard to administrate. So I would like to use a more efficent way. May thought was to Query a DataTable, make changes to it and then call .AcceptChanges and all changes where wrote back to the Database. But this seems not to be the way it works?The method .Update requires that i bring with my own update command, if i have to do that myself, why using the datatable, dataset... anyway?How do you write your DB Backend?
With SQLCommands arrays and variables?
With DataSet, DataTable?
With a VisualStudio genereated template?
With Linq?
C# - How To Get Distinct Values From DataTable In DataSet
Dec 23, 2011I am using strongly typed dataset and have many tables in that. The problem is now I want to filter data from
GetData()
function which has a query like
select * from table_name
How can I filter a particular table and distinct values from it. Also if I try to filter it return all column but rest have null values except the one I asked, so I cannot assign it as a datasource to a datagrid or combobox. How can I do this..
Convert A List To Dataset Or Datatable?
Jun 5, 2011I need to convert bindiangsource.datasource (which is a list) to dataset or datatable.
View 1 RepliesCreate A DataView From The Dataset / Datatable?
Jan 2, 2010How to create a dataview from a datatable?
What is the basic use of the created dataview?
Dataset - Print Out Rows From A Datatable In .net?
Dec 31, 2011I am new to vb.net and I am trying to query a database and print out the records in the row to the console window. I got it to work, but I have a feeling that there is a more concise way to do this. One thing that I am sure is wrong is that I had to convert the dataset to a datatable to be able to retrieve the values. Is that correct? Could you take a look at the code below (especially the for loop) and let me know what I can improve upon?
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HTMl Table To Datatable Or Dataset
Nov 4, 2009asn1.htm (14.26K)
Number of downloads: 248Private Sub Command1_Click()
Dim HTML As HTMLDocument
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Import Dataset / Datatable Into Sql Table?
Sep 15, 2010I've been fighting with this problem for 2 weeks now and haven't been able to figure it out to parse data from a text file to a datatable using SteamReader. I am trying to import the data like it is displayed in the datatable into SQL Server 2005, I have tried using sqldataadapter approach, the standard approach, ADO.NET approach. [code]...
View 8 Replies