Visual Studio - when to call update on a tableadapter - vb.net

I'm new to Visual Studio - migrating from Microsoft Access and Dynamics AX where updates to physical tables happen pretty much automatically for a simple data grid.
In my Visual Studio VB form project I have a datagrid component bound to a tableadapter. I can double-click a cell and edit the contents, then move to another row. But my changes are not being committed to the dataset's table.
Even though the tableadapter has an update method, apparently it is not called automatically. Do I have to call the tableadaptor's update method to save the user's data changes in the grid?
If so, how do I detect when datagrid cells values have been changed? Or do I simply call update every time the user leaves a row and let the update query run even with no changes?

Related

Referencing fields in ACCESS DB in Visual Studio for WinForm App

Newer to getting started with Visual Studio, but running into an issue i'm certain the pro's on here can answer.
I have an ACCESS DB data source connection to the Windows Form App I am building with Visual Basic programming in Visual Studio. For some reason when debugging, it is saying there is no amount of rows in the data, but clearly there is when you see the picture. I simply wanted to have a label update if a selection is made from a combo box based on a column and row entered on the data source.
How do I properly reference the Row 1, Column "BOM" from the Access DB in my line of code for the value to show up as "Dawn Page" for the label text? I get you have the 'datasource.datatable' precursor to the rest.

Deleting data using gridview

I would like to delete a record from my table using grid view, I have tried many different ways of doing this however when the form is closed and re-opened the data returns. (Just the form not the program)
I am aware that visual studio resets all changes once the program is closed. My add and modify data buttons are both working fine and if I close the form and reopen the changes remain. However I can’t seam to do the same with delete, unless I am missing something obvious =S.
These are the routes that I have tried, I am coding using visual basic.
Method one:
StudentBindingSource.RemoveCurrent()
Method two:
BindingNavigatorDeleteItem.PerformClick()
To save new data I use the following which works fine:
StudentBindingSource.EndEdit()
StudentTableAdapter.Update(Database1DataSet)
If I remove a record using one of the methods above and then click save I get the following error:
Update requires a valid DeleteCommand when passed DataRow collection with deleted rows.

How Does Visual Studio/VB Create and Initialize a Table Adapter?

I have a very simple Windows form application that uses a data set. I am having trouble figuring out how Visual Studio creates a new Table Adapter object and then initializes that object through its insertion of initialization code into the .Designer.vb files. My problem is I have inadvertently caused this to happen through some series of commands I do not remember, and am trying to figure out how to re-create what I did.
For example, if I want the data set to be used by a form, I know this goes in the form's Designer.vb module
Friend WithEvents StreetsTableAdapter1 As WindowsApplication1.DataSet1TableAdapters.streetsTableAdapter
However, this line alone won't instantiate the table adapter object.
As to the data set, I've created a one; configured one of its table's table adapters to use SQL queries; tested those queries; and they work.
I'm more interested in what Visual Studio writes to create the new object rather than the keystrokes to do it, because I'd like to know what's going on underneath the covers, rather than relying on keystroke magic.
I have a workaround
Me.StreetsTableAdapter1 = New DataSet1TableAdapters.streetsTableAdapter
I've added this to the form's .Designer.vb file. I'm still trying to figure out what I did in Visual Studio to get all this initialized through running some specific commands.
A pointer to an example would help, as well as the steps to make this happen. Then, I'll examine what Visual Studio does, so I do not get stuck again.
The easiest way to create the table adapter on your form is to let Visual Studio do it for you. In the toolbox "DataSources", you should see your current data. You can expand the nodes and drag the fields/tables to your form. This will create the table adapter and everything needed behind the scenes.

How to refresh a dataset to reflect external changes to the database?

In a WinForms application that uses a dataset from a data source created using the Data Source Configuration Wizard and connected to an Access database. How can I refresh the dataset at run time to reflect changes (data changes only, no structural changes) to the database occurred outside without closing and reopening my application?
Thank you ahead of time for your help.
Call the .fill command on the tableadapter that the wizard should have created.
By default the code is placed in the load event of the form that you added the tableadapter and dataset to, so either copy paste or creat a new sub and call that.
Edit:
There is a clearBeforeFill property of any tableadapter listed under the TableadapterManager in the Form designer if you added it via the designer, if not then you'll have to set it in your code behind.
in the code behind there are several events that can occur on your binding source, I would suggest putting the needed code on the currentItemChanged event in order to commit changes in real time.

vb.net combobox data changes

I am making my final year VB.NET project, I am using Visual Studio 2008 with 3.5 framework
I am making a Restaurant Bill generation software.
I have created the table in SQL and connected to the project, I added 6 combo boxes with drop down,
I have assigned drop-downs as the Menu item of the restaurant, when I run the program and try to change one combo box item, all combo box items get changed. How can I avoid this?
How to get rid of this?
I am not a professional in this, but any help will be appreciated
I would guess that you've bound them all to exactly the same BindingSource (which is pointing at the same data), in which case changing the selection in one combobox will immediately be reflected in the others. If you have multiple items bound to the same BindingSource (which is what the wizard will give you if you're not careful), and don't want a change in one to reflect in the others, you need to create separate BindingSources for each one.