Change QueryString value on Button click using C# in ASP.Net

Hi nauna,

Check this example. Now please take its reference and correct your code.

CS.aspx

<asp:Button ID="btnNext" Text="Next" runat="server" OnClick="btnNext_Click" />

CS.aspx.cs

protected void btnNext_Click(object sender, EventArgs e)
{
    Response.Redirect("Default.aspx?ID=1");
}

Default.aspx

<asp:Button Text="Check" runat="server" OnClick="Increment" />

Default.aspx.cs

protected void Increment(object sender, EventArgs e)
{
    if (!string.IsNullOrEmpty(Request.QueryString["ID"]))
    {
        int id = Convert.ToInt32(Request.QueryString["ID"]);
        Response.Redirect("Default.aspx?ID=" + (id + 1));
    }
    else
    {
        Response.Redirect("Default.aspx?ID=1");
    }
}

Screenshot