Asp.net/c# -> Gridview Pager doesn't get updated when gridview rows are filtered (or hidden)

Question

I have the below code where I have some conditions because of which I have to hide the row from showing to end user. "ShowRow" is a boolean value that gets set in GetUnitOfMeasure function (not copied here) based on these conditions.

There are some real conditions which is forcing me to hide. I tried to include them while building data source but I have to hide it before display.

Problem I am facing is the paging is not getting refreshed based on total rows shown at the end. For example, if I have TOTAL of 200Rows in the grid and only 2 rows needs to be shown and if these 2 rows are found in paging 3, then when page is loaded it still shows paging 1 2 3 4 and 3rd page has the valid 2 rows.

Please suggest.I have also used "onDataBound" against gridview (not copied here) but I just hide some columns here.

ASPX page

<asp:GridView ID="SearchResults" runat="Server" AutoGenerateColumns="false" EnableViewState="false"
AllowPaging="true" PageSize="50"  OnDataBound ="SearchResults_DataBound" OnRowDataBound="SearchResults_RowDataBound">
<RowStyle CssClass="EvenRow" />
<AlternatingRowStyle CssClass="OddRow" />
<Columns>
    <asp:TemplateField meta:resourceKey="UmSellField">
        <ItemStyle CssClass="alpha" />
        <HeaderStyle CssClass="alpha" />
        <ItemTemplate>
            <asp:Label ID="UmSellLabel" runat="server" EnableViewState="false" Text='<%# GetUnitOfMeasure(Container.DataItem,false) %>'></asp:Label>
        </ItemTemplate>
    </asp:TemplateField>
</Columns>
</asp:GridView>

codebehind

protected void SearchResults_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType.Equals(DataControlRowType.DataRow))
    {
        e.Row.Visible = showRow;
        e.Row.Cells[0].Visible = showRow;
    }
}