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 need to select all records from Table2 where there are NO records in Table1 having matches of both Col2 & Col3. For instance, Table 2 records where Table1.Col2 <> Table2.Col2 AND Table1.Col3 <> Table2.Col3.
Let say I have a function inside a class which require 4 parameter (table name,field name,field value, return field) When I use this function my form, such as
myclass.Search("customers", <-- after pressing the "," a popup list will be displayed that contain all the fields in "customers" table.
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.
i have the following function to update my database:
Public Function Alterar(ByVal registro As Bancos) As Boolean Dim Key As EntityKey Dim OriginalEntity As Object = ""
[code]....
i want create a change log, to do this, i need pick up every records changed and insert it in other table to make a log.How can i pick up this changes?
I'm currently refactoring an old Visual Basic DLL (VB.Net), which stores all of its data in one module called Globaldefinitions as public fields. There are about 200 fields, referenced thousands of times all around the code:
Public Module Globaldefinitons Public a As Short ... Public zz10 As Double
[Code]...
I need to change the module into a class with non-shared fields. This means, each and every of these thousands of references needs to reference the instance of that class:
globalDefinitionsInstance.a = 5
How do I go about this efficiently?
Regular expressions operating on the source fall flat. Refactoring tools like Re-Sharper or CodeRush don't seem to offer this functionality. Visual Studio 2010 cannot do it automatically either.
Class Foo ReadOnly name As String Public Sub New(name As String, dependentUpon As Foo) Me.name = name
[code]....
The output of New Bar() is:
Dependent created. Dependent upon nothing. Independent created. Dependent upon nothing.
It seems fields are initialized in the same order as they appear in the source code, which (a) leads to an unexpected result, and (b) seems a little puzzling, given that one is normally not permitted to read from uninitialized variables in .NET, yet that seems to be working fine above.I would've expected VB.NET to be smart enough to initialize referenced fields first, and only then those that reference it; i.e. I'd have liked to see this output instead:
Independent created. Dependent upon nothing. Dependent created. Dependent upon Independent.
how to get VB.NET to behave like that instead, without simply having to swap the declaration order of dependent and independent inside class Bar?
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 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.
Currently working on a project to automate the input based on the Summary file (xls format)
1. I want to be able to do the following: update, append, delete and populate the records to the various files based on two distinct fields, column A & F (see attached file).
2. Researched the process, requires knowing VB codes, are you familiar with this language? If so, how can I simplify the process? Please advise.
I have a class being populated from comma separated rows in a text file.I am trying to have the name property of each object appear in a listbox, then have the rest of the properties of a selected object show up in text boxes. How do I load the properties of the selected object to the correct textbox?
in my form, I want to display a 200x200 table each field containing a 16x16 image. There should be no space between fields, and the fields need to be selectable... how to create such table.
I have been using the code below to edit SQL database fields from the data stored in a dataset. Problem is I have to repeat this long code for each database field to be edited....I find this very tiring...IS THERE A SHORTER WAY OF EDITING SQL Database FIELDS. (Am using VS 2005 and SQL Server 2005
'3. Create an Update command Dim strUpdateAccounts As String = "UPDATE Accounts SET Description = @Description" 'create a SqlCommand object and assign it to the UpdateCommand property
Assume my form has four text boxes and it's bond with a Dataset, therefore The user can 1-4 fields. Typically I write one update statement that take four input parameters. Therefore I update the updated fields as well as non updated field. To do this in the proper way, how many update statements I have to write? Or How do I do this update properly? I use SQL server 2K5
I will post a sequence of examples and thought about sql injection, I wish the expert will correct any small mistake in what I will say so I can know exactly the possible danger.
The required is to create a function in vb.net that accept 2 parameter (table_name, fields_list) and return the result in datatable
Now, I am aware of that table_name and fields_list cannot be passed as parameter to the command object using .AddParameter
here is a couple of thoughts, what I would like to know is
1- which function is exposed to sql injection
2- Which function is more safe
Public Class Form14 Dim conn as New SqlClient.SqlConnection(connection_string) Private Sub Button1_Click( ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Im builtina an windows application based on 3 tiers model. I have BLL, DAL, and UI Class. IN DAL I have SQL code, In BLL I have proprietie and methods .Im trying to validate the input fields on BLL class and no problem,and im just do it after SET instruction. I also PUT a message to view error. But From BLL class I want to put the focus in textfield that return error. I cant acess form proprieties (the forms are on UI class).
Using myConnection As New System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & databasePath & ";User Id=admin;Password=;")
[Code]......
This did not work but did when i just tried creating the table and not the fields.
Have anyone developed a textbox where it is possible to display 2 fields in the textbox. We want to be able to show ID + description in the same textbox. (When user enter the textbox description may go away and the user can enter an ID)
What i'm trying to do here is login using a table and fields with username and password and also usertype in it. If the user is an Admin then it displays the the command button cmdAdmin and if not admin it disables it. This is the code that i currently have at the moment Hope someone can help me out and also i want to get rid of the username and password that's currently in it and use database instead.?
