<obout:Grid id="Grid1" runat="server" Serialize="false" OnDataSourceNeeded="Grid1_DataSourceNeeded"..>
    <Columns>
        ...
    </Columns>
</obout:Grid>

protected void Grid1_DataSourceNeeded(object sender, GridDataSourceNeededEventArgs e)
{
    int maximumRows = e.MaximumRows;
    int startRowIndex = e.StartRowIndex;
    string filterExpression = e.FilterExpression;
    string  sortExpression = e.SortExpression;

    // Perform query against the database using the above variables
    // Retrieve a DataSet containing the fresh set of data
    // ...

    // Get the total count of rows from the database
    // ...

    // Pass the total number of rows to the "TotalRowCount" property of the event object
    e.TotalRowCount = count;

    // Bind the Grid to the new data source
    Grid1.DataSource = ds.Tables[0];
    Grid1.DataBind();
}