hai,
try this
Try
strSql = "select col1,cl2 from table1"
'execute sql and save it in tbk1 datatabel
tbl1 = objDb.getTable(strSql)
'add default select column
dim drw as datarow
drw = tbl1.NewRow
drw.Item("col1") = "Select"
tbl1.Rows.Add(drw)
combo1.DataSource = tbl1
combo1.DisplayMember = tbl1.Columns(0).Caption
combo1.ValueMember = tbl1.Columns(1).Caption
combo1.SelectedIndex = -1
combo1.Text = "Select"
then
<pre lang="sql">
dim strSql as string =select * from table 2
where
'some condition
If combo1.Text.ToLower.Trim <> "select" Then
strSql &= and table2.column= combo1.SelectedValue
End If
</pre>