Object-Orientation - Implement The Class And Access The Database For Values?
Dec 17, 2009
I've now properly started implementing OO into my system (which I probably should have done from the start) but I just want to clear some best practices.So let's say I have a class called Job which contains information such as Description, Project Manager (Employee class), Value etc. at the moment, if I initialise the Job class it will initialise all the information held within it, even if I only want the job description. Is it best practice to do this or is it better to implement the class and access the database for values as and when they're needed? Or is it just better in those cases to just access the database directly?
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Jul 29, 2010
how variables declared with protected access in a base class are used to implement inheritance.
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Aug 18, 2009
I have some classes, BsfciFile and StudyFlashCard. Bsfci is the extension to which I save my set of flashcards in an INI format. I am currently working to transform my code from using Windows API calls to access the INI to using a IniFile class that I found on the internet. I would like the BsfciFile to have a Array of StudyFlashCard objects, but I would like the StudyFlashCard class to use the IniFile class object contained in the BsfciFile class. I can pass the IniFile from the BsfciFile class to the constructor for the StudyFlashCard class, but I want it to modify the same IniFile as the BsfciFile class has later on.
[Code]...
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Nov 22, 2010
I created an interface - TermsService.vb and defined the following method : Function GetTermsList() As List (Of Terms)
how do I modify my TermsDB class to implement the TermsService interface I've just created? Here is my code: Have I implemented it correctly?
Imports System.Data.SqlClient
Friend Class TermsDB
Implements TermsService
[Code].....
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Jul 5, 2010
bare with me during this silly example. :-) Let's say I have a class like this:
Public Class Animal
Public iLegs as int32 ' Number of legs
Public bWings as Boolean ' Wings? Yes/No
End Class
And another class that inherits the "Animal" class and adds one more property:
Public Class ScaryAnimal
Inherits Animal
Public iScariness as int32 ' 0-100, how scary is it?
End Class
Now, if I have an instance of "Animal" with some values in it, and I decide I want to cast it to a ScaryAnimal for some reason, how do I do that without having to create a new instance of "ScaryAnimal" and copy each property value?Basically I'm looking for a way to do this, without having to write the lines marked with '*** below:
[Code]...
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Sep 27, 2011
I have been requested to implement a login form into a friend's Visual Basic .NET application. He specifically requested that I should do this using LINQ to compare the input to a table in an Access database. I don't really know why he imposed these restrictions, but who am I to judge? However, the problem is I am not overly familiar with VB .NET, or LINQ.
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May 3, 2011
I was create Access database with Access 2003. I create VB project with Visual Studio 2005 Standard With connection wizzard I create coonect with this Access database, select all tablesI see this database inside Data sources and inside Server explorer Test connection is OK When I drag and drop table from Data sources, Wizzard don't create DataGridView, DataSourceBinding etc .. and I see popup window with mesage: Object reference not set to an instance of an object and then "game over"
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Mar 14, 2011
I'm writing an asp.net page with a simple registration form that connects to my access database and inserts the values in the table. So I have my database, my registration page, everything looks fine in my code, but there's a syntax error I can't seem to figure out. When I go on my webpage and click submit, it says : Syntax error in INSERT INTO instruction.
Here's my code:
<%@Page language="vb" explicit="true" debug="true"%>
<%@Import Namespace="System.Data"%>
<%@Import Namespace="System.Data.OleDb"%>
[CODE]...
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Oct 22, 2009
I want a string and a listbox, both which are in a form to be modified by an instance of a class method. Should (could I):
1. Pass the entire form to the class method as parameter.
2. Pass the listbox and the string to the method as parameters.
What's the best approach to get access and modify this string and listbox on the form.
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Jun 6, 2010
I created a dataset and i am using OleDbDataAdapter to insert new values to access database. But when i close the program and after open it, values are not in the database. How can i solve this problem? Also, i have another problem. When i write codes that
[Code]...
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Mar 1, 2010
I need to create unit testing project for my current website. The currentw ebsite si written in VB. All unit testing examples are using interface to create mock object. My current VB class does not implment any interface. Can I add interface and implement it to my current class and functions without affecting or changing codes to any pages in my website that call the functions? For examples my current class is like:
[Code]...
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Nov 17, 2010
quite new to database queries through VB. I have just created a DB using MS Access and I need to write data to it from my VB Application.Can anyone point me on which objects should I use to execute these write transactions?
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Jun 10, 2011
Suppose I have piece of code like this:
Public Interface ISomething
....
End Interface
[code]....
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Feb 19, 2010
I am working on a general helper class to sort ListView SubItems. I wrote a base class that has much of the code I need. It includes a MustOverride for the Compare method so that the various inherited classes can implment their own comparisons based upon their type. For the value types, I end up with very similar code such as the following, where x and y are ListViewItems: Public Overloads Overrides Function Compare(ByVal x As Object, ByVal y As Object, ByVal sortColumnIndex As Integer, ByVal sortOrder As System.Windows.Forms.SortOrder) As Integer [code]
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Mar 5, 2012
how do i get the values from my database in access in vb i have a table named Rates that has column PerMinute and column Amount
i want to access the data in the amount column. and make it appear on the AmountToPay.text
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Jun 18, 2009
class inherit from another class and implement an interface?
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Apr 29, 2009
So I already have a smartphone application, and I already connected it to my database. How do I get data from that database to be loaded into the form? For example, I got a table 'Shops' with a column 'ShopType'. I want to put all shop types in a comboBox when a soft key is clicked.
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Jun 8, 2011
I am making a database project in vb.net. I have one table which has 9 columns. I am using ms access database as server side. my question is that, how to insert rows with values in a table.
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Apr 1, 2010
The following is the code i used to get the value from textbox to listbox and store all the listbox values to the access database at the runtime.In the database, i have only one field called num which is been set as a multivalue field using the lookupwizard. But actually what happens is ,no error is occurred,but the value is not updated in the batabase.
vb.net
Imports System.Data.OleDb
Public Class Form1
Dim conn As OleDbConnection[code]...
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Aug 10, 2010
I am making a application that has the ability to edit values on a access database table. As a simple example, My table looks something like this:
Order Number Completed
2000 No
2001 No
2002 No
The application needs to edit the Completed columns. I have 1 text box, and 1 button in my form. You enter the Oder Number in the textbox and press the button. The VB application then needs to change the Completed to Yes in the database. Example, I type in 2002 in the textbox and press a button. The application changes Completed to Yes for this order number in the access database and saves/updates the database.
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Dec 15, 2011
I have a table called tblComparison - this table has the following columns[code]...
Once the averages for each column are created it needs to save them to tblMonthlyComparison - again the column names in this table are the same so in the fldDate column the program needs to enter 31/12/2011. In fldAverage of this table what we do is take the average that we found above for each column then plus them together and divide them by 5.
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Nov 2, 2010
I am a total beginner to Visual Basic and have a project to conduct a survey for my company. The Answers of the users need to be populated to the database. So far, all I've managed to do is to define a string which will have the answer to be updated into the access table. How am I supposed to pass the value?
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Mar 3, 2009
I want to create a Web Service that will insert values into a access database. Probably be something like this but dont no the code enough to complete:
[WebMethod]
public void CreateUser(string name, string password) {
msConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=R: C:events.mdb"
****Insert code e.g. INSERT INTO eventstbl(User, pass) Values(name, password)***}
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May 17, 2012
Here is a class to SQL use an access database:
Class MyDB
Public DBName As String
Private con As New OleDbConnection(ConStr)
[code]....
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Oct 20, 2009
I have been trying for 2 weeks now to get this program to work.I am using VBasic and MS Access 2007 in conjuntion with a software application.the Database has 2 fields
1) Text
2) OLE Object (.jpg)
when I try to preview the data inside the DataSet I can only get the text to come threw, but that isn't the problem...the problem is binding the data to a datasource and displaying the information.I cannot get the database to display the information in FIELD 2
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Mar 30, 2011
There is an OLE object column that contains images in my access database. I'm trying to create a program that reads the images from that ole column and store the images to a file. Currently, I have a program that creates an image file but the image is blank.[code]
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Oct 22, 2010
how to implement UI, BL and DAL in a project the way that I see it as a requirement for some projects. The way I am able to do a project now is from a form create an object of a class in which there are properties and functions that do database selects, updates and deletes. Looks to me that doing a project like that is separating the UI from the DAL. In an update button click event I may call Obj. Delete (txtCustID.txt) for example. I don't understand the part of further breaking it down to include a Business layer; in which a vb solution is made up of three solutions.What goes in the BL?Does the BL call the DAL?
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Jun 7, 2010
I am utilizing a centralized class object that needs to call another class object. The program itself will do something like the following
sFieldValue = CentralObject.ObjectHandler(1, TestFunction, "FunctionVar,FunctionVar2,FunctionVar3")
In the central object I have a function
Public
Function ObjectHandler(ByVal ObjectType
As
Integer,
[code]....
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Jul 10, 2010
I am somewhat new to object oriented programming and am attempting to flatten a Linq object hierarchy by using a shim class.how to initalize a derived class with property values from a base class?I have two objects, a base object with about 100 properties, and a derived object which inherits from the base object and adds a few additional properties beyond those of the base object. My simple constructor creates the derived object, but I am looking for a way to initialize the derived object properties with values from the base object.Right now I am using reflection to iterate over the properties individually and I suspect there may be a better way. The following example shows my shim class constructor for the derived class, and two properties:
newProperty1 - a new string property of the derived class
flattenedProperty2 - a new string property of the derived class, copied from a 2nd-level object of the base class
Code example:
Public Class derivedObj
Inherits baseObj
Private _newProperty1 As String[code].......
Is this the correct constructor approach to flatten the object hierarchy using a shim class? My second question relates to initialization of properties in the derived class. The constructor above creates the derived object, but what is the best way to initialize the derived object properties with values from the base object? The following code uses reflection to iterate over the properties individually, but I suspect there may be a better way.
Code example:
' property names are in the string array fieldNames
'baseObjQuery is an ienumerable of baseObj
'derivedObjList is a list of derivedObj[code].....
Is there a simple way to initialize values for the properties in the derived object based upon the values of the common properties in the base object?
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Jan 5, 2010
How update the Access database in VB.Net with NULL values using OLE DB command
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