Send (Pass) GridView Row Values to next page using Session variable in ASP.Net

First page html:

<form id="form1" runat="server">
    <div>
        <asp:GridView ID="gvModule" runat="server" AllowPaging="False" AutoGenerateColumns="False"
            CssClass="gridView">
            <Columns>
                <asp:TemplateField HeaderText="ID">
                    <ItemTemplate>
                        <asp:LinkButton ID="btnPassRowData" Text='<%# Eval("mod_id") %>' runat="server" OnClick="PassData" />
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:BoundField DataField="age" HeaderText="Age" />
                <asp:BoundField DataField="salary" HeaderText="Salary" />
            </Columns>
        </asp:GridView>
    </div>
    </form>

first page c# code:

protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
            DataTable dt = new DataTable();
            dt.Columns.AddRange(new DataColumn[3] { new DataColumn("mod_id", typeof(int)), 
                            new DataColumn("age", typeof(int)), 
                            new DataColumn("salary",typeof(int)) });
            dt.Rows.Add(1, 21, 15000);
            dt.Rows.Add(2, 22, 16000);
            dt.Rows.Add(3, 25, 18000);
            dt.Rows.Add(4, 24, 17000);
            gvModule.DataSource = dt;
            gvModule.DataBind();
        }
    }

    protected void PassData(object sender, EventArgs e)
    {
        GridViewRow gr = ((sender as LinkButton).NamingContainer as GridViewRow);
        Session["age"] = gr.Cells[1].Text.Trim();
        Session["salary"] = gr.Cells[2].Text.Trim();
        Response.Redirect("DataPage.aspx");
    }

second page html:

<form id="form1" runat="server">
    <div>
        Age:
        <asp:TextBox ID="txtAge" runat="server" />
        <br />
        Salary
        <asp:TextBox ID="txtSalary" runat="server" />
    </div>
    </form>

second page c# code:

protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
            txtAge.Text = Session["age"].ToString();
            txtSalary.Text = Session["salary"].ToString();
        }
    }