VS 2010 - Update Information And Declaring Record In Class
Sep 26, 2011
I have a collection of objects (classes I created), and each one ties to a record in a database. I want an easy way to update the information, so I thought about declaring a record in the class, that would tie to the record on the database. However, I'm having a problem updating it now.
1) Can I declare a global variable for the data context, and leave it open the entire time the program is running? This would solve my problem, but I don't know if I can do that.
2) If not, besides coming up with a complicated class to do this, is there an easier way? Here is an example of what I am trying to do:
VB.NET
Public C as Record
Public Sub GetValue()
Dim SQL As New DBDataContext
Dim X = From T in SQL.Records Select T
[Code] .....
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Jul 16, 2010
I'm new at vb.net programming so be gentle. I have the flowing code
Dim dAdapter = New OleDbDataAdapter("Select * from items", dbConOra)
Dim dTable = New DataTable()
dAdapter.Fill(dTable)
BSourceItems.DataSource = dTable
DataGridVew1.DataSource = BSourceItems
[Code]...
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Nov 15, 2009
I have a problem with my program, and it's really bad because I need to burn it to disk within 12 hours and I can't get it to work: If I create a record, add information to it and click on Next Record, the ID, Status and Notes boxes content will change but the rest of the controls contents are carried over to the next record and I don't know why or how. It was working perfectly but now it stopped and I never done anything.
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Jun 13, 2010
Is there a direct way of generating a class from a record in the database?I use a program to edit records and would like to use a class that has the record fields as member for saving the last values entered while adding new records and the initial values of the fields for editing so that if i press ESC the control while editing the value returns to the original.I tried to use dim r as datarow but i get the error that there is no object
and if i declare dim r as new datarow i get the error that new is not implemented.Do I have to write the class definition explicitly?
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Jun 7, 2012
how to edit and update in relational table's record in visual basic 2010?
have two tables with Relationship
1, Orders
2, Order_Details
"Orders" Related with "Order_Details" ( OrderID )
now i want to Edit and update. Record in "Order_Details" ( "Pencil" to "Pencils" ) Then Update changes
my code is below
Dim CurOrder_DetailsRow As OrdersDataSet.Order_DetailsRow
CurOrder_DetailsRow = CType(CType(Me.Order_DetailsBindingSource.Current, DataRowView).Row, OrdersDataSet.Order_DetailsRow)
[Code]....
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Feb 22, 2011
Ok, basically i have 3 different classes: one is a NormalUser, one is a SuperUser, and one is an Administrator. I have on one of my form loads an if statement like this:
If frmLogin.lstCurrentUserData(frmLogin.lstCurrentUserData.Count - 1).Contains("Normal") Then
Dim player As New NormalUser
[Code]....
So based on an item in a list, i want to create a new instance of that class to be my player. now i know that code doesn't work, because the variable is only present within the if statement. my question is, how can i declare "player" as a new instance of the correct type, and still be able to access it in other subs?
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Nov 23, 2009
I had a problem with CLR profiler. But it worked eventually and the results were outstanding. My app took 47 milliseconds to run before and after some adjustments CLR profiler runs in 6 miliseconds! This had to do with String values in a resource file which apparently takes a lot of time. So this got me thinking, isn't it more effective if you would declare 1 String at the top of your class and constantly change it throughout your code? Instead of creating a new String in a method when you need it.
Instead of using:
Dim text = "blalblalba"
You would do this everytime you needed a string:
text = "blalbla"
My question is... What exactly happens when you say text = ""? Does .net create a new String? It looks like you replace the text but what happens in the background? Would it be faster then declaring a new string?
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Mar 5, 2010
What's the proper way to declare variables in a class? I've been doing something like:
'in a class
public shared teststring As String = "first"
'on a code behind
[Code]....
with shared variables loading a second window or reloading the page (without clicking the button) renders the hello world string. so how do I declare variables in a class but make it per instance?
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Mar 30, 2011
I'm trying to develop a class in VB .NET in order to manage a language globalization stored in a database and editable by the user.What I need is to know what kind of class I need to declare in order to use it without declaring a new object. For example, the way My.Settings is used.
One of the goals is that in some project the developer imports the reference and after that access directly to a property. For example: My.CustomLanguage.GetWord("Hello") without declaring objects.
Is this possible? And if it's what is the best way to aproach it?
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Oct 27, 2009
I am handling many of the BindingNavigator tasks (MoveFirst, MoveNext, etc.)in code to ensure that I always ask the User to save his changes.
The one area I am have a problem is PositionItem. I would like to sense that the User has changed the Record Number in the BindingNavigatorPositionItem, handle my record Update, and move to the Record Number the User entered I have looked all over and have not found any way to do this.
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Apr 5, 2011
I have a class that I would like to link at construction to a given control (say a textbox)
I know I can put a variable into a subroutine referentially but is there a way to store it in the same capacity?
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Oct 20, 2008
I've decided to forget the d@mned custom code because everything I do with comes up with errors I don't know how to fix and it seems no one else does either. Or they do and they're keeping to themselves.
I put the functions that I needed to use in a class called MsgBoxOperations. The file name is MsgBoxOperations.vb In the report, up on the standard bar where file, edit, view, and all the other stuff is, is one that says report. You click that and go to report properties and it brings up where you can name the report and put in custom code...(hate custom code right now...) and where you can put references and class instances. Clicking on the Reference tab brings up wher you put in your references and classes.
In the classes area it asks for the Class Name, which I put in MsgBoxOperations, and the instance name of that class, this case mbo. I get that far and put in those two things and save it. Then I go to the textboxes where the values need to be. I put in the text box: =Code.mbo.GetStartDate
I've already tried taking the Code. part out and it screams that mbo isn't declared. So it does have to be there. I go to run the code and comes up with this error: QuoteError in class instance declaration for class MsgBoxOperations: [BC30002] Type 'MsgBoxOperations' is not defined.
I've posted before and still have received no help or someone tried to help but then stopped when their suggestion failed and then no one else wanted to help. I've googled this problem to the point where every link that it comes up with I have already clicked and found their information useless. I've got a freaking migraine because of this issue and have been in tears over it more than once.
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Jun 28, 2009
how do i use a class without first declaring an instance of it with the new keyword?i have a class items that has a function toArray.how can i call it this way:
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Aug 5, 2010
I have a base class foo that will be used in multiple child classes of similar but slightly different function:
Public MustInherit Class foo
Public Function bar1() as Something
''// Perfectly OK to change what this method does
[code]....
How do I get the compiler to generate an error when bar2() is overridden by a child class?
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Jan 6, 2011
Is it possible for a class of exposing a type for function returns, without allowing users of that class to create variables of that type? A couple usage scenarios:A Fluent interface on a large class; a statement like "foo=bar.WithX(5).WithY(9).WithZ(19);" would be inefficient if it had to create three new instances of the class, but could be much more efficient if the WithX could create one instance, and the other statements could simply use it.A class may wish to support a statement like "foo[19].x = 9;" even when foo itself isn't an array, and does not hold the data in class instances that can be exposed to the public; one way to do that is to have foo[19] return a struct which holds a reference to 'foo' and the value '19', and has a member property 'x' which could call "foo.SetXValue(19, 9);" Such a struct could have a conversion operator to convert itself to the "apparent" type of foo[19].In both of these scenarios, storing the value returned by a method or property into a variable and then using it more than once would cause strange behavior. It would be desirable if the designer of the class exposing such methods or properties could ensure that callers wouldn't be able to use them more than once. Is there any practical way to accomplish that?In formulating a question, it's difficult sometimes to draw the line between complicated usage cases, and simpler usage cases which aren't quite so important. Here's another usage case, and one closer to the one I'd be most interested in (though I'm also interested in Fluent chaining; being able to have something behave like a C++ reference to a value type would be nice, but probably too much work to bother with).I have a type which is somewhat like the Windows registry, in that it is a hierarchical collection of items, each of which may have a string value, an integer value, and/or a nested collection of items. I wish to be able to support the following types of usage:[code]As for the Fluent interface, my thought would be to have the WithXXX properties return a new instance of a derived class which shadows (not overrides!) the WithXXX properties with versions that simply modify the current instance. The return object from WithXXX would be known to be of the derived class, and would thus use the shadowed WithXXX methods, but once it was assigned to a variable, it would be regarded as an instance of the base class, so the next WithXXX would create a new instance.
C++ a stronger concept of value types than C# or vb.net, including the very useful concept of references to value types; it ensures that references to value types cannot be persisted outside the scope of the type in question. Unsafe code in C# can use pointers to value types, but they don't have the protections offered by C++ references.
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Dec 2, 2010
How to use this query to update record [code]....
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Jun 27, 2011
I'm writing a class that represents a diagram (an image). Within that class, there is textbox class. That is, each diagram can have any number of textboxes on it. I want each instance of the textbox class to have access to the members of its parent diagram class. Specifically, I would like each textbox class to be able to access the instance of the Drawing.Graphics object located in the parent Diagram, so it can handle the drawing of itself
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May 4, 2009
When I am on my modify page and you scroll through the records with the Binding Navigator, somehow the previous records data stays on the screen and puts it into the next data. Now this only happens on my one screen with 2 combo boxes. How do I get my information to stay put so that users don't have to worry about scrolling through multiple records and screwing up the data?
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Feb 11, 2012
Having problem declaring constant on Visual Basic. rents is $200 per hour and is charge by minutes this is what I have so far.
const TOTAL_CHARGE_GROUP as Interger = 200 ©
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Mar 25, 2011
My question centers upon the two approaches, (1) and (2), shown below, to declaring Excel workbooks in .Net.The two approaches interact differently with the lines "wkbk10 = app.wkbk10.open()" and later with
Range references to this workbook,like "rng1Stocks = CType(wkbk10.Sheets(1), Excel.Worksheet).Range("H5:H30")".
[code]....
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Mar 12, 2010
What is the difference between using the 'array' class in VB and just declaring an array like normal. In other words, what is the difference between:
Dim numOfTicketsPerDay As Array
Dim intNumOfTicketsPerDay(6)
As Integer
Is there any preference of when one should be used over another?
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Apr 16, 2011
I'm maintaining a Datagridview on my Windows Form. When I open the form all the contained records are displaying, which is from SQLserver Table ok. when I open the form the datagridview should show just black and after I insert a new record that particular record should only display on that form gridview. [Code]
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Mar 11, 2010
I am creating a update member page. I would like the page to auto retrieve the information he or she originally used while registering on my site and display them into the individual textboxes of the update profile page, this is to prevent the hassle to rekey in every individual details and allow the user to edit what he or she wants before it is updated into the database. The problem that I encountered was not able to update the changes in the database. When key in the latest data in address text box and hit submit button, the old data in address text box remains and did not update the database
Imports System.Data
Imports System.Data.SqlClient
Imports System.Web.Configuration
[CODE]....................
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Apr 17, 2009
I'm using VB.NET to perform a SIMPLE record update. I don't understand why this is not working. Perhaps it's because the form is open while executing? I'm not sure. I'm using an Access backend.
[Code]...
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Mar 11, 2010
I am trying to update a sequence of records where the field WebSvc = No
Here is the code
cn.Open()
da = New SqlDataAdapter("SELECT * FROM dbo.DurexBOL", cn)
cmdBuilder = New SqlCommandBuilder(da)
[Code].....
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Oct 10, 2010
I have created a class called clsTest, this contains the sub "logInfo", when this is called within another class (e.g. "clsOther") some information about the other class is logged to a file.
I want clsTest to be able to get some general information about clsOther, specifically it's type and/or the sub/function that called the "logInfo" sub in clsTest. I could pass these as additional arguments in the "logInfo" subroutine but I was wondering if it was possible for clsTest to know what had invoked it (or any other class for that matter).
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Nov 26, 2009
I have a dataset with a number of data columns, due to sizing issues I've updated a number of the varchar columns from say VARCHAR(20) to VARCHAR(50).I'd like the DataTable to automatically grab the new column information, is this possible? I'd rather not go through each column in the table and update the length.
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Jun 7, 2012
i have a requirement where in i have to update the information of a record with new values.how to open the binary file and update with the new information.The existing binary file contains 5 records with serial nos.now i want to update the information of sno 1.i am using filestream, binary reader ,binarywriter SureshThere is an Island of Opportunity In the Middle of Every Difficulty
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Jun 8, 2012
i have to update an existing binary file with new information.
binary file contains records from 1 to 5 each record contains different values one integer and five strings.
no i have to update the 1 record with the new information .how do i do that.
i am using filestream,binary reader and binary writer.
Pwd_FS = New FileStream("test.bin", FileMode.Open, FileAccess.Read)
after reading the contents of the record i will assign new values to the recorod writing back should i use
Pwd_FS = New FileStream("test.bin", FileMode.Append, FileAccess.Write) if i use append i am not able to seek to the starting point.
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Jun 12, 2009
I want to update a record in my database but without using "update mytblname" query. I am using following code:
sql = "select * from customer where id = " & Val(Me.id.Text)
Dim adapter As New SqlDataAdapter(sql, conn)
Dim builder As SqlCommandBuilder = New SqlCommandBuilder(adapter)
Dim ds1 As New DataSet("customer")
adapter.Fill(ds1, "customer")
[Code] .....
This code is not working. Means no error and data is also not getting updated.
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