Beginner's Question--accessing database server

[gary]

Hello I am trying to access my data using some of the examples on the VB Resource CD to learn about VB.net. I have used the following code:

Public Sub InsertRow(ByVal myConnectionString As String)
MyConnectionString = "database=Northwind;Server=localhost"
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim myConnection As New SqlConnection
Dim myInsertQuery As String = "INSERT INTO Customers (CustomerID, CompanyName) Values('NWIND', 'Northwind Traders')"
Dim myCommand As New SqlCommand(myInsertQuery)
myCommand.Connection = myConnection
myConnection.Open()
myCommand.ExecuteNonQuery()
myCommand.Connection.Close()
End Sub 'SelectSqlClientSrvRows


When I click f5 and run the app, I get no compile errors. When I click on the button, however and attempt to access the server, I get the following error:

An unhandled exception of type 'System.InvalidOperationException' occurred in system.data.dll

Additional information: The ConnectionString property has not been initialized.

Additional information is as follows:
1. I have Visual Studio.net installed with MSDE on my computer. In my server explorer I have the following items showing.
SQL Servers ---GARYLAP\INSTANCE--------

2. Under the GARYLAP\INSTANCE I have the following databases:
Master
Model
MSDB
Northwind

I have modified the connection string until I finally gave up. I tried server =garylap and garylap\instance but to no avail. Any help would be greatly appreciated.

Thanks,

Gary

 

[Hussein Abuthuraya[MSFT]]

Gary,

In your code, you didn't set the connectionstring for the connection object
unless you didn't include it all. You have InsertRow function that takes
one parameter but it does nothing. Propably what you need to do is:

- Remove InsertRow function since it is redundant.
- Modify Button2 click event code to:

Dim ConStr as String =
"Server=yourMSDEinstancename;database=Northwind;Integrated security=SSPI"
Dim myConnection As New SqlConnection(ConStr)
Dim myInsertQuery As String = "INSERT INTO Customers (CustomerID,
CompanyName) Values('NWIND', 'Northwind Traders')"
Dim myCommand As New SqlCommand(myInsertQuery)
myCommand.Connection = myConnection
myConnection.Open()
myCommand.ExecuteNonQuery()
myCommand.Connection.Close()
End Sub 'SelectSqlClientSrvRows

I hope this helps!


Thanks,
Hussein Abuthuraya
Microsoft Developer Support

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[Guest]

You may also need to change the server name from "localhost" to "(local)" or to the IP address "127.0.0.1". Localhost may not work because of name resolution issues unrelated to your code issues. I had that problem.