无效的 CurrentPageIndex 值

private void Bind()
{
prjFactory.LeaveWord lw = new prjFactory.LeaveWord();
prjSystem.Qualifier qlf = new prjSystem.Qualifier();
DataTable ds = lw.queryAsDataTable(qlf);
this.DataGrid.DataSource = ds;
try
{
this.DataGrid.DataBind();
}
catch//(Exception e)
{
this.DataGrid.CurrentPageIndex=-1;//返回上一页
this.DataGrid.DataBind();
}
}