asked on

Moving past VB6 to Visual Studio 2010

I'm finally leaving the VB6 world...have Visual Studio 2010 installed. I've created a project and dropped some controls on it...just as an exercise, I want to populate my combo box from a command button click event. Of course I'm getting a runtime error, "ArgumentException was unhandled" on the ComboBox1.DataSource = objReader line. Do I have to reference something like I would in VB6? How does it know which field I want to choose for the combo box? I don't even know if I'm connected to the db. Will some kind Expert help me take this first step?

Public Class Form1

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
      
Dim strSQL As String

strSQL = ""
strSQL = "SELECT * FROM myDB.myOwner.myTable ORDER BY MyField"

'Establish connection and open database connection
Dim objConnection As New SqlClient.SqlConnection("server=mySQLServer;database=myDB;user=myUser;pwd=MyPWD")

'Establish command object
Dim objCommand As New SqlClient.SqlCommand(strSQL, objConnection)

Dim objReader As SqlClient.SqlDataReader

objConnection.Open()

objReader = objCommand.ExecuteReader

ComboBox1.DataSource = objReader

objReader.Close()

objConnection.Close()

End Sub
End Class

Open in new window

Carl Tawn

You can't use a DataReader as the datasource of the ComboBox as it only accepts objects that implement the IList or IListSource interfaces.

You can find a simple example here that uses a DataTable instead:

http://msdn.microsoft.com/en-us/library/w67sdsex(v=VS.90).aspx

Or you could try this:

   '// you want to be careful about using * in select statements!
   Dim strSQL As String = "SELECT * FROM myDB.myOwner.myTable ORDER BY MyField"

   'Establish connection and open database connection
   Dim objConnection As New SqlClient.SqlConnection("server=mySQLServer;database=myDB;user=myUser;pwd=MyPWD")

   'Establish command object
   Dim objCommand As New SqlClient.SqlCommand(strSQL, objConnection)
   Dim adap As New SqlDataAdapter(objCommand, objConnection)

   Dim ds As New DataSet()
   adap.Fill(ds)

   '// tell the combobox which fields to use
   ComboBox1.DisplayMember = "Name of column for text display"
   ComboBox1.ValueMember = "Name of column for underlying value, probably an ID of some kind"

   ComboBox1.DataSource = ds.Tables(0)


End Sub

Open in new window

x77

Windows Form Contros DataReader do´nt support DataReader as DataSource.
You can do it with Web Controls.

For Windows App use a DataTable as DataSource:

Dim Dt as new DataTable
Dt.Load(objReader)
ComboBox1.DataSource =Dt

or

Dim Dt As new DataTable, Da as new SqlClient.SqlDataAdapter(strSQL, objConnection)
Da.Fill(Dt)
ComboBox1.DataSource = Dt

MariaHalt

ASKER

Thanks for the quick reply, I'm getting a different error: Type 'SqlDataAdapter' is not defined.

Éric Moreau

you can use SqlCient.SqlDataAdapter

MariaHalt

ASKER

Still getting an error: Type 'SqlCient.SqlDataAdapter' is not defined.

'Dim adap As New SqlDataAdapter(objCommand, objConnection)
Dim adap As New SqlCient.SqlDataAdapter(objCommand, objConnection)

ASKER CERTIFIED SOLUTION

Carl Tawn

membership

Create a free account to see this answer

Signing up is free and takes 30 seconds. No credit card required.

See answer