Paging for Gridview doesn't work correct - asp.net

Question

I have a search page. In list the search results are displayed.
When I select another page from page numbers, the search result is disappeared and show the list like the page is refreshed. What should I do? I tried OnSelectedIndexChanged and OnSelectedIndexChanging. And didn't work. Thank you.
<asp:GridView ID="GridView1" runat="server" AllowPaging="True" AutoGenerateColumns="False"
CellPadding="4" DataSourceID="ahsun" ForeColor="#333333" GridLines="None" Width="100%"
DataKeyNames="SICIL_NO" OnSelectedIndexChanged="LinkButton1_Click" CssClass="icerik" o >
<FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
<Columns>
<asp:TemplateField ShowHeader="False">
<ItemTemplate>
<asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" CommandName="Select"
CssClass="hover" Text="Seç"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Adı" SortExpression="ADI">
<ItemTemplate>
<asp:LinkButton ID="LinkButton3" runat="server" Text='<%# Bind("ADI") %>' CausesValidation="False"
CommandName="Select" CssClass="hover"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Soyadı" SortExpression="SOYADI">
<ItemTemplate>
<asp:LinkButton ID="LinkButton4" runat="server" Text='<%# Bind("SOYADI") %>' CausesValidation="False"
CommandName="Select" CssClass="hover"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Birimi" SortExpression="BIRIMI">
<ItemTemplate>
<asp:LinkButton ID="LinkButton5" runat="server" Text='<%# Bind("BIRIMI") %>' CausesValidation="False"
CommandName="Select" CssClass="hover"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Görevi" SortExpression="GOREVI">
<ItemTemplate>
<asp:LinkButton ID="LinkButton6" runat="server" Text='<%# Bind("GOREVI") %>' CausesValidation="False"
CommandName="Select" CssClass="hover"></asp:LinkButton>
</ItemTemplate>
</asp:TemplateField>
</Columns>
<RowStyle BackColor="#EFF3FB" HorizontalAlign="Left" />
<EditRowStyle BackColor="#2461BF" />
<SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
<PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
<HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" HorizontalAlign="Left" />
<AlternatingRowStyle BackColor="White" />
</asp:GridView>
<asp:SqlDataSource ID="ahsun" runat="server" ConnectionString="<%$ ConnectionStrings:oraLiveConnectionString %>"
ProviderName="<%$ ConnectionStrings:oraLiveConnectionString.ProviderName %>"
SelectCommand="select SICIL_NO, ADI, SOYADI, BIRIMI ,GOREVI,PERSON_ID from xxah_hr_calisanlar WHERE SICIL_NO <> '01470' "></asp:SqlDataSource>
<br />
<asp:DetailsView ID="DetailsView1" runat="server" CellPadding="4" DataKeyNames="SICIL_NO"
DataSourceID="SqlDataSource1" ForeColor="#333333" GridLines="None" Height="50px"
Width="100%" CaptionAlign="Left" AutoGenerateRows="False" CssClass="icerik">
<FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
<CommandRowStyle BackColor="#D1DDF1" Font-Bold="True" />
<EditRowStyle BackColor="#2461BF" />
<RowStyle BackColor="#EFF3FB" HorizontalAlign="Left" Width="75%" />
<PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
<FieldHeaderStyle BackColor="#DEE8F5" Font-Bold="True" Width="25%" />
<HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" HorizontalAlign="Left"
Width="25%" />
<AlternatingRowStyle BackColor="White" />
<Fields>
<asp:BoundField DataField="ADI" HeaderText="Adı" SortExpression="ADI" />
<asp:BoundField DataField="SOYADI" HeaderText="Soyadı" SortExpression="SOYADI" />
<asp:BoundField DataField="BIRIMI" HeaderText="Birimi" SortExpression="BIRIMI" />
<asp:BoundField DataField="GOREVI" HeaderText="Görevi" SortExpression="GOREVI" />
</Fields>
</asp:DetailsView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:oraLiveConnectionString %>" EnableCaching="True"
ProviderName="<%$ ConnectionStrings:oraLiveConnectionString.ProviderName %>"
SelectCommand="select c.* from TABLE c where c.SICIL_NO=:sicil" >
<SelectParameters>
<asp:ControlParameter ControlID="GridView1" Name="sicil" PropertyName="SelectedValue" />
</SelectParameters>
</asp:SqlDataSource>

Answer 1

For pagination You need to work on PageIndexChanging.Nothing to do with OnSelectedIndexChanged.
For Example:
Method
protected void BindData()
{
string strConnection = "Data Source=.; uid=sa; pwd=wintellect;database=Rohatash;";
SqlConnection con = new SqlConnection(strConnection);
con.Open();
SqlCommand cmd = new SqlCommand("select * from Userinfo", con);
DataSet ds = new DataSet();
SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(ds);
GridView1.DataSource = ds;
GridView1.DataBind();
con.Close();
}
PageIndexChanging
protected void GridView1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
GridView1.PageIndex = e.NewPageIndex;
BindData();
}

Answer 2

Try enabling ViewState on the datasource in your aspx page by adding EnableViewState="true" and ViewStateMode="Enabled"