Database Stuff In Each Form Separately - Place It In A Global Module - Dataset Is Being Duplicated ?
Apr 19, 2011
I have finally got my code all working, but there is just a quick query really. At the moment I have all the database stuff in each form seperatly. When I place it in a global module, it looks like the dataset is being duplicated I was wondering why this happens when I place it in a global module?
This the code I use and the code I would put in a global module
Dim con As New OleDb.OleDbConnection
Dim dbProvider As String
Dim dbSource As String
i could use Global x as string in vb6 in a module to declare it with global privelages, how can i do this in vb2008? how to declare a global variable in vb2008? so that i could use it anywhere i want. i know global variables are not recommended in programming but i need one.
how to place stuff on forms and such but not much else so i was wondering if a book was better to use to learn or something from a website? if book which books should i check out or which website?
I'm having trouble updating a sql server database with a dataset using a dataadapter. I have used the dataadapter with success in the past when adding new rows, using a single table, and just calling the dataadapter.update command.However, I am now running into a more complex scenario and I need to use dataadapter.UpdateCommand method and I'm having lots of problems.
The sql statement that I'm using to fill the dataset looks like this: "Select [Order Details].ProductID, [Order Details].UnitPrice, [Order Details].Quantity, [Order Details].Discount, Products.ProductName From [Order Details] INNER JOIN Products ON [Order Details].ProductID = Products.ProductID Where OrderID='" & strOrderID & "'", sqlConn"
This is pulling the data from 2 different tables (Order Details and Products) and then joining them and filling the dataset, and I am seeing the exact results I want. I am then binding the dataset to a datagrid control that allows the user the option to edit the datagrid, which in turn updates the dataset.
So that being said how do I get the updated dataset back into the database? I tried using dataadapter.update but it informed me that I now need to use dataadapter.UpdateCommand. Ok, so I've looked up how to use UpdateCommand but I cannot for the life of me figure out how to set up the right sql command statement. Part of what has me confused is the UpdateCommand examples I have seen are working with a specific row and updating that rows data. I can get that to work but I want all changes to the dataset to persist and update to the database when the user is done working on the datagrid.
Also, the examples shown set up command parameters but again, this is only confusing me because I just want to send the whole dataset back to the database. It seems like the parameters are saying "Ok, this specific row in this specific dataset.table, update these specific fields in this specific database". I'm not sure how to accomplish that when working with a datagrid.
I've got a console app with a sub main then i have a seperate class inside the module..i can't seem to update the public global variable from inside the class as i can't declare the variable as shared...
I am wanting to populate a form with check boxes and labels on starting of the app. My idea is to store to locations on the form in a database. I am creating an app that would have check boxes and labels that the user could check off to store points for completed tasks. The tasks on the form could change so I want the form to change as the tasks are changes with out re-coding the app.I am using VB 2003. I have searched but couldn't find anything.
I have a form set up where I want to run the function PopulateGrid on it's Form_Load event. I have initialized the DB connection as follows:
Private Sub Main_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load LoadConfigFile() cn = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" & config("DatabasePath") & ";") cn.Open() End Sub
Now, I want to run the PopulateGrid function directly after I connect to the database as shown above. I'm confused as to how I'd use a database query in a module when the database is initialized in my main form. Would simple setting the variable cn to public work?
I have a Form with a TextBox, and a Save button that saves the text as a .rcp (txt) file. Now I want to add a button that browse for an image that accompany that txt file, and load it into a Picture Box. When I click to Save the txt file, I want it automatically to also save the loaded image With the txt file as the same name as the txt file, without needing to save the image and text separately.
I have this code for my save button: Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click SaveFileDialog1.CreatePrompt = True SaveFileDialog1.OverwritePrompt = True ' Set the file name to myText.txt, set the type filter [Code] .....
I want to create a dataset that I can access from any form. I already created the tables and columns using the dataset designer. I read that I can declare the dataset as public in a module, but when I try to access a table I have to put the name of the module in front otherwise I get a "Reference to a non-shared member requires an object reference" error. When I declare a variable as public in a module I never have to specify the name of the module to access the variable, so why do I need to do it for a dataset? The code in my module is:
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So Im making a program with 2 different data tables where different columns from those tables are used in different tabs in the same form. This all works good and well so far, but I have one issue which just drives me mad, and a couple minor ones.
1. I have an ID column in each data table marked as Primary Key, Unique and Identity. Problem is that even if I choose to hide this column it just randomly decides if it actually is visible or not. Most often its visible. I dont get it, doesnt this function work? Do I use it wrong? Im not using any code for this, just right click on the data grid, press Edit Columns... And change the Visible to False. It works for all other columns all the time as far as I can tell, but for my ID column its just random.
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Okay what I have saves my stuff to the database. However, when I rebuild my application the previous data is gone. The data is loaded into datagridview using
Frontend: Visual Basic.Net VS: VS 2010 .net Framework: 4.0 Backend: MySQL 5.0. Everything is working well, add/edit/save. I am using datasets to manipulate the database the forms are created by wizard and i drag and drop the details over the form. The Problem: I delete a record on the form, it disappears (it deletes it from dataset i think) but i go to the database it is still there also if i close the form and re-open it the records re-appear.
There is something i do but it raises an error, after deleting the records i hit the save button,the following comes up. Transaction has already been rolled back or is not pending after that the records are really deleted.
I'm quite new to databases so this might be a very basic question: How does one replace a table in a local MS Access database with a new dataset?
I'm able to read the contents from the database into the dataset DatabaseDataset, change it so it looks perfect, but when I update the Access database, it only adds the dataset instead of replacing the existing contents. I tried to clear the contents of the database, but that doesn't work either.
i am working on a project! the problem i am having is that i have two combo box first combo box takes stuff form the file and then add it to listfile it also removes that selected file from the combo box.suppose i have four carid in my combo box...when i select one car and then send it to dispatch it removes form tht combo box and add it to the lst file... this much i can do. is i need that carid that removes from the combo box should add in another combo box ... but i cant able to do it
Public Class MainForm Private strCarID() As String Private strTime As DateTime Private strDate As DateTime
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how to do a delegate for my lstView1 to display the stuff that taken out from the database? I keep display the error on ListView1.Items.Add(myReader("Int_Name" )).Error: System.InvalidOperationException: Cross-thread operation not valid: Control 'ListView1' accessed from a thread other than the thread it was created on.
Private Sub DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived Dim strSql As String
I seem to have a major problem. when I add a typed dataset to my project and go back to my sql server and click on the databse I use it doesn't open. the tables and stuff just vanish. using the wizard, it creates this connectionstring:
It connects fine. but after I try opening it in sql server i get an error. It doesnt let me restore or anything. i tried restarting my pc incase the db was locked but it is still gone. now my app cant connect. Just for clarity, is user instance supposed to be set to true. and what is the purpose of it. also when the wizard asks to make a copy of the file that will be copied accross each time I run my project I select No.
just as what i mentioned in above, the problem is i add a new windows form, in which is a database with dataset, in the main form when i press a button. this database form should come out, i used the easiest way like form2.show(), while conforms
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The following code does create a form within a form and does place NotePad inside the child form. You have to manually start NotePad prior to execution (I work on that later) but the code does workŠ My problem is now I want to manipulate the properties of notepad i.e. focus, size, location, etc. but I cannot figure out how to reference notepad and its properties.
I have a problem saving a dataset which contains rows that i have imported from another dataset. i can successfully view the imported rows in a gridview but i cannot commit the rows back to the database.
