I am using Visual Studio 2022 (VB.Net) and SQL Server 2022 Express. I am not a programmer; I just like teaching myself coding and trying to learn.
I have a program, and I am trying to access the data in the table I created, but when I try to connect a DataGrid view to the table there is nothing there. See the screenshots.
If someone could give me a hint, it would be greatly appreciated.
SQL Server
Imports System.Data.SqlClient
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Using connection As New SqlConnection(
"Server=localhost\SQLEXPRESS;" &
"Database=master;" &
"Trusted_Connection=True;")
Dim adapter As New SqlDataAdapter("select * from spt_values", connection)
Dim table As New DataTable
adapter.Fill(table)
DataGridView1.DataSource = table
End Using
End Sub
End Class
MySQL
Imports MySql.Data.MySqlClient
Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Using connection As New MySqlConnection(
"server=localhost;" &
"port=3306;" &
"database=sakila;" &
"user=root;" &
"password=********;")
Dim adapter As New MySqlDataAdapter("select * from city", connection)
Dim table As New DataTable
adapter.Fill(table)
DataGridView1.DataSource = table
End Using
End Sub
End Class
SQL Server. The class names are slightly different: SqlConnection instead of MySqlConnection. I just couldn't post the untested code.
Fill and Update will both open the connection if required and leave the connection in the same state as it was originally. That means that any single call to Fill or Update should not be preceded with a call to Open on the connection. If you're making multiple calls though, you should call Open and Close yourself or else the connection will be closed and reopened between Fill or Update calls.
DataGridViewor any other controls directly from a database. You use some data access technology to retrieve the data into a list of some sort and that list is the data source for the grid. You should learn about data access technologies in VB and WinForms first. You can use vanilla ADO.NET, as per the first comment above, or you can create a typedDataSet, or you can use Entity Framework, or you can use some other ORM. The choice is yours. Once you have such a data source, that can be used to populate your grid.