Generate Dynamic TextBoxes based on the count value in QueryString in ASP.Net

    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
        <Columns>
            <asp:TemplateField>
                <ItemTemplate>
                    Enter Product
                    <%#Eval("ItemId") %>
                    Quantity :
                    <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        int count = int.Parse(Request.QueryString["count"]);
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[1] { new DataColumn("ItemId") });
        for (int i = 0; i < count; i++)
        {
            dt.Rows.Add(i + 1);
        }
        GridView1.DataSource = dt;
        GridView1.DataBind();
    }
}

You can pass the count via querystring and then use GridView to generate dynamic textboxes