get_owner()

<telerik:RadGrid RenderMode="Lightweight" ID="RadGrid1" runat="server" AllowPaging="True"
    OnNeedDataSource="RadGrid1_NeedDataSource">
    <MasterTableView DataKeyNames="OrderID">
        <Columns>
            <telerik:GridTemplateColumn DataField="ShipCountry"
                FilterControlAltText="Filter ShipCountry column" HeaderText="ShipCountry"
                SortExpression="ShipCountry" UniqueName="ShipCountry">
                <ItemTemplate>
                    <asp:TextBox ID="TextBox1" runat="server" Text='<%# Eval("ShipCountry") %>'
                        onchange='<%# "textBoxChange(this, event,"+Container.ItemIndex+",\""
                    +Container.OwnerTableView.ClientID+"\");" %>'>
                    </asp:TextBox>
                    <telerik:RadTextBox RenderMode="Lightweight" ID="RadTextBox1" runat="server" Text='<%# Eval("ShipCountry") %>'
                        ClientEvents-OnValueChanged='<%# "function(s,a){valueChanged(s,a,"+
                    Container.ItemIndex+",\""+Container.OwnerTableView.ClientID+"\");}" %>'>
                    </telerik:RadTextBox>
                </ItemTemplate>
            </telerik:GridTemplateColumn>
        </Columns>
    </MasterTableView>
</telerik:RadGrid>

function textBoxChange(textBox, event, index, tableViewID) {
    var tableView = $find(tableViewID);
    var row = tableView.get_dataItems()[index];

    var grid = tableView.get_owner();
    alert("Grid ID: " + grid.get_id());
}
function valueChanged(sender, args, index, tableViewID) {
    var tableView = $find(tableViewID);
    var row = tableView.get_dataItems()[index];

    var grid = tableView.get_owner();
    alert("Grid ID: " + grid.get_id());
}