PagedDataSource Count

我使用pageddatasource对datalist控制进行分页，但是当将pageddatasource绑定到linq查询时，虽然查询结果不同(ResultQuery_Count = 13和PagedDataSource计数总是10)，但计数并不改变。IsFirstPage和IsLastPage也总是为真

代码如下:

PagedDataSource objPage = new PagedDataSource();
try
{
    objPage.AllowCustomPaging = true;
    objPage.AllowPaging = true;
    objPage.DataSource = Getter.GET_GeneralResult();
    objPage.PageSize = 8;
    objPage.CurrentPageIndex = CurrentPage;
    lbtnNext.Enabled = !objPage.IsLastPage;
    lbtnPrev.Enabled = !objPage.IsFirstPage;   
    DataList1.DataSource = objPage;
    DataList1.DataBind();
}
catch (Exception ex)
{
    throw ex;
}