vb.net windows form select query using postgresql server - vb.net

Question

I am new in vb.net, how do i conduct select query in my windows forms using postgresql server?
this is my connection, (actually i dont know if this is working but i didnt receive any error and the message box appear if i button is clicked)
here is code so far
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim MyCon As New Odbc.OdbcConnection
MyCon.ConnectionString = "Driver={PostgreSQL ANSI};database=*****;server=localhost;port=5432;uid=postgres;sslmode=disable;readonly=0;protocol=7.4;User ID=******;password=*****;"
MyCon.Open()
If MyCon.State = ConnectionState.Open Then
MsgBox("Connected To PostGres", MsgBoxStyle.MsgBoxSetForeground)
End If
End Sub

Answer 1

In .Net we have Using...End Using blocks that will close and dispose objects that use unmanaged code. Connections fall into this type of object; any object class that has a .Dispose method.
You can pass your connection string directly to the constructor of the connection.
We also have Try...Catch...Finally....End Try for exception handling.
To test your connection:
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
Using MyCon As New Odbc.OdbcConnection("Driver={PostgreSQL ANSI};database=*****;server=localhost;port=5432;uid=postgres;sslmode=disable;readonly=0;protocol=7.4;User ID=******;password=*****;")
MyCon.Open()
End Using
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End Sub
For help with the connection string itself check https://www.connectionstrings.com/postgresql/
There are several ways to query your database in ADO.net. Study up on ADO.net. The following is one way.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt As New DataTable
Try
Using MyCon As New Odbc.OdbcConnection("Driver={PostgreSQL ANSI};database=*****;server=localhost;port=5432;uid=postgres;sslmode=disable;readonly=0;protocol=7.4;User ID=******;password=*****;"),
cmd As New Odbc.OdbcCommand("Select * From SomeTable;", MyCon)
MyCon.Open()
dt.Load(cmd.ExecuteReader)
End Using
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
DataGridView1.DataSource = dt
End Sub