Create A Class To Deal With Records From The Classes Table?
Dec 5, 2010
Create a class to deal with records from the Classes table, much like the Student class we created in Lecture #17 handles Students records. The name of the class should be Ualb_Class (note we cannot use Class, as it is a reserved word in VBA). All of the fields should have corresponding properties. There are few considerations:
The class (course) code, department code, and course number are set at Initialize, so there is only a Get property method for those
The property for Meeting Day only accepts one of the values defined in the table. You can decide whether to accept an integer value or a string value of the days represented.
You are also to code the Initialize method, much like we coded the Initialize method for the Student class in Lecture #17. In the Initialize method, you will use the InputBox function to obtain the department code and course number. use a different InputBox for each value, so you don't have to mess with separating the single text value returned from that function. The Course Code will be obtained by using a function that has already been created, called GetNewCourseID. It has no parameters.
slno Name Age City 1 Ron 22 Dallas 2 Jonny 26 Texas
Now i use the following method to access data:
Try Using connection As New SqlConnection("Data Source=.SQLEXPRESS;AttachDbFilename=E:Visual Studio 2008ProjectsSmart SyncronixSmart SyncronixSmartDB.mdf;Integrated Security=True;User Instance=True")
Okay, say I have a class named "ChannelList", and it raises an event named "FoundChannel"
But what I'M wanting to do is create multiple classes of different names that use that class, but I want to have all of the "FoundChannel" events be handled under one single sub routine?
In my first attempt to create a Class that contains something useful (if you will), I am a little lost what a sound way to proceed is. I am trying to make a table that has fields and records. Perhaps imagine a tiny spreadsheet. So, I create my Class. Properties might include the number of columns, the column titles, and the number of rows or records. I then think the thing to do is create a couple of structures to be used within the class. Thus far I have this:
Imports System.Console Public Class ConsoleTable Property NumberofCOlumns As Int32
[Code]....
Problems I am creating in my mind include:
1) In the Field Structure, could I make the FieldValue so that I can change the data type? Meaning sometimes I want an instance of a Field to hold a string,or an integer, or a decimal.
2) In the Record structure, for any given instance of one I don't know the number of fields it will hold until I create the new instance. I tried Public RecordFields(FieldCount) As Field in the Structure, but that's not allowed. I then used Public RecordFields() As Field, and then in my code used the ReDim method. Is there a better way?
3) With the Table Class, same problem. The number of records within any instance of the class needs to be dynamic.
I have an interface that i have declared some of the basic internal functions, subs, properties, etc. This interface is then implemented into 3 pre-defined classes. These classes are end-use classes so they dont get derived or inherited elsewhere. I am trying to create a generic shared class that can operate on each of these 3 predefined classes and potentially more as long as they implement the interface.
i have a datagridview with (a lot of) rows. With a click of a button I add them into a table. Everything works fine. I want to create a log of the records that have been added into the table.
I am cleaning up some code and I have multiple classes that are 99% exactly the same. So my understanding is that my options are...
1. Create a class and all other classes inherit from it and modify it a bit
2. Create an abstract class and all classes inherit from it and modify a bit ** I took this route
3. Create an interface and all classes Implement that interface.
Here is my 'original' class below (the one that all of them look 99% identical). This class is used in an arraylist so I have a listing of all my images from a folder I have searched.
I am woking on an application in which records of a table are stored in another table. In case of duplicate records they will not wriiten to the table and they should be written in a log file.
How can I structure my classes so that the user interfaces though a single class while the supporting classes are hidden from their view? I think its best understood in an example:
Public Class MyInterface Public Economic as EconomicClass Public Sub New() MyBase.New()
[code].....
So you might ask why am I even separating them? It's strictly for others who will be working with this interface. I need to funnel them though a logical structure:
This way everything is already handled for them in the background and they only need to run the method they need. I don't know if I can have it both ways in VB.NET.
I have a database with 3 tables: Student, Unavailability and Duty.The fields for Student are entered in a form I have. One of the fields in Unavailability is filled by a form, the other fields are an autonumber and a foreign key to the Student table.ow I want records in the Duty table to be created and automatically filled in depending on what the values of the fields are in the Student table.For example, If the Boarder field in the Student table is 'yes' then I want the Duty Number field in the Duty table to be '1', '3' and '4'. If it is 'no' then I want the value to be '2' and '5'. I recognize it will have to create several different records to incorporate the different duty numbers for each StudentID. Obviously this will require an if statement, however this is my first time implementing a database with my limited experience with programming and Visual Basic, so I don't know how to refer to the specific fields in a table and set the value of other fields depending on the data in other fields.
I recently downloaded VB2008 express. Iam trying to create a link to an SQL table, but the LINQ to SQL class is missing in my add new item menu. is there another way to grab data from a database without using the LINQ to SQL?
I want to create a class (I think) that has properties that correspond to column names in a database table, such that they come up in Intellisense when I type the dot after the class name. Is this possible to do?
I have this piece of code wich works perfectly when inserting records into one table using records from another table. My question is that now i need to create another table by using records from 3 other tables (tables are related). Can i use aliases on the column names, like on Oracle SqlPlus? How will be the syntax of the 'INSERT INTO SQL statement?
Dim MyConn As ADODB.Connection Dim MyRecSet As ADODB.Recordset Dim tmpSQL As String MyConn = New ADODB.Connection
I do this in Oracle databases just in a snap, but now I have to do it in VB using ADODB and I don't know how to do it.
I have two Access 2007 tables. Table A contains: Col1 (text), Col2 (text), Col3(date), Col4(amount), Col5(text)
Table B contains Col1(date), Col2(amount) What I need to do is to insert into table B the records of table A (col4 summed) grouped by date of table A. The date is a variable contained in a text box so it cannot be hardcoded into the SQL statement.
I am trying to create a class whose end result is do create an XML document. Currently the class consists of nested classes that each build a section of the XML document. What I am hung up on is how I should tie the results of the inner classes for the final output.Should the outer class pass an instance of XmlTextWriter to each of the inner classes that build up specific sections or should each innerclass just output a string representation of the XML and the outer class can piece them together?
[code]...
The code is not complete but I hope it gives an idea of what I am trying to accomplish. I need to find a way to gather XML sections together to output as a single document.
I'd like to be able to log to the console every time an event is fired either in the object I've instantiated or in anything it's instantiated [ad infinitum]. I wouldn't see some of these events normally due to them being consumed further down the chain). Ideally I would be able to log all public and private events but if only public are possible, I can live with that.
I've Googled and all I can find is how to monitor a directory - So I'm not sure if this is not possible or simply has a name that I don't know.
The sort of information I'm after is similar to what's found in an exception - Target Site, Source, Stack Trace, etc...
Could I perhaps do this through reflection somehow?
To Give you an idea of the console App:
Sub Main() Container = ContainerGenerate.GenerateContainer() Dim TemplateID As New Guid("5959b961-b347-46bc-b1b6-cba311304f43")
I'm working on a class project where I have to create an item class with private attributes, public get and set methods for the attributes, and two non-access methods. I have two textbooks I work with. The first book is Clearly Visual Basic(Zak) and the second is Programming, Logic, and Design(Farrel). I've set my private attributes but I am having difficulty writing what I want to accomplish in the VB.net language.
Class CD1 Declarations private string cdName private string aristName
I have a class SELF that is hosted by a couple different classes. Basically, the hosting class HOST calls a method in SELF. SELF is passed HOST as an argument in the constructor, so SELF can call methods in HOST. In normal situations, a call to HOST will do something minor, then return so that SELF can continue. However, for one particular type of HOST, one of the calls from SELF to HOST will cause HOST to call SELF, and so on ad infinitum. A classic, though convoluted, case of recursion. Once again, this is only going to happen for one type of HOST. For other types of HOST, that particular call will not cause HOST to call SELF, so there will be no recursion. Nonetheless, there is no getting around it in one case.
I can see two means to decouple the recursion, and I am wondering which one (or a third) would work best:
1) Add a timer into that particular HOST so that the call from SELF that would trigger the recursion would actually just start the timer in HOST, then return. When the timer ticks, HOST can call SELF. The recursion is broken because the call to SELF is done on the timer event, and not when SELF called HOST.
2) As it happens, HOST makes the first call to SELF in a background thread, which means I don't really need to worry whether this thread blocks or not. Therefore, I could have this background thread spawn a second background thread to make the call to SELF, then have the initial HOST thread JOIN on the second thread. This means that the initial thread will block until the second thread finishes. Meanwhile, the second thread will call HOST, and the HOST won't call back to SELF, it will just return like all the other HOST objects would do. This will allow the second thread to run to completion. When the second thread completes, the first thread will take over and call SELF again on a new second thread. Therefore, the recursion is broken because the secondary thread will always run to completion, and the primary thread will wait for the secondary thread to complete, then call it again.
I tend to prefer the second option, because the first option involves a pause of some length (the minimum for a timer, which is pretty small), while the second doesn't, but the first option is actually a little easier to implement.
I'm wondering on how you would go abouts instantiating a class that contains other complex objects. for example an Payment Class which has Date,Time, etc.. and it also holds a reference to a paymethod object which has id,Type,Description etc.. How do you instantiate the payment class with all the other objects without one or the other failing, how do you create the payment class which doesn
I have to convert a set of C# classes (class library) to SQL tables to be used by SQL Server, so that the data can be stored in a database and manipulated through the database.The problem is that the number of these classes is big (more than 1000 classes),and it would take a long time to setup manually such a database schema (tables,ndexes, stored procedures, etc.) - not to mention the class hierarchies that I need to maintain.
I will preface this by saying Im previously an asp developer and am learning oop programming/Vb.Net
Im working on a 3 tier architecture and trying to abstract my code as much as possible since I have a very large intranet to convert. In my business layer I am defining my classes with management methods. Below is an example of one of my classes.
My question: Is there a way for me to genericaly refer to the class type and object type so that I dont have to continualy refer to the class name/type "ServiceRequest" throughout the class. For example something like:
You 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.
