Private Function Does Not Working?

private void Form1_Load(System.Object sender, System.EventArgs e)
{
Dim stri As String
stri ="SELECT allowType fROM SLABS order by allowtype"
this.FillCombo(stri, Cmballowa);
}
private void FillCombo(string ssql, object cbo)
{
SqlDataAdapter da = default(SqlDataAdapter);
SqlConnection con = new SqlConnection();
DataSet ds = null;
DataView dv = null;
con = new SqlConnection(constr);
da = new SqlDataAdapter(ssql, con);
ds = new DataSet();
da.Fill(ds, "ITEM");
dv = ds.Tables("ITEM").DefaultView;
cbo.DataSource = dv;
}

But here some error message is coming in "private FillCombo function" like "'object' does not contain a definition for 'DataSource' and no extension method 'DataSource' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)" So, how can i correct this error?