in row databound event
Dim dtPriceSource As New DataTable()
dtPriceSource = CType(Session("123"), DataTable)
Dim ddl As DropDownList
ddl = New DropDownList()
ddl = CType(e.Row.FindControl("ddl"), DropDownList)
Dim mypricesouce As String = ddl.Text
ddl.DataSource = dtPriceSource
ddl.DataBind()
ddl.Items.Insert(0, New ListItem(" ", 0))
If IsDBNull(Gridview1.DataKeys(e.Row.RowIndex).Values(0)) = True Then
ddl.SelectedValue = 0
Else
ddl.SelectedValue = Gridview1.DataKeys(e.Row.RowIndex).Values(0)
End If