NameValueCollection data = new NameValueCollection();

        data.Add("v1", "val1");

        data.Add("v2", "val2");

        HttpHelper.RedirectAndPOST(this.Page, "2.aspx", data);

using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Net;

using System.Collections.Specialized;

using System.Text;

/// <summary>

/// Summary description for HttpHelper

/// </summary>

/// <Author>Samer Abu Rabie</Author>

public static class HttpHelper

{

    /// <summary>

    /// This method prepares an Html form which holds all data in hidden field in the addetion to form submitting script.

    /// </summary>

    /// <param name="url">The destination Url to which the post and redirection will occur, the Url can be in the same App or ouside the App.</param>

    /// <param name="data">A collection of data that will be posted to the destination Url.</param>

    /// <returns>Returns a string representation of the Posting form.</returns>

    /// <Author>Samer Abu Rabie</Author>

    private static String PreparePOSTForm(string url, NameValueCollection data)

    {

        //Set a name for the form

        string formID = "PostForm";

        //Build the form using the specified data to be posted.

        StringBuilder strForm = new StringBuilder();

        strForm.Append("<form id=\"" + formID + "\" name=\"" + formID + "\" action=\"" + url + "\" method=\"POST\">");

        foreach (string key in data)

        {

            strForm.Append("<input type=\"hidden\" name=\"" + key + "\" value=\"" + data[key] + "\">");

        }

        strForm.Append("</form>");

        //Build the JavaScript which will do the Posting operation.

        StringBuilder strScript = new StringBuilder();

        strScript.Append("<script language='javascript'>");

        strScript.Append("var v" + formID + " = document." + formID + ";");

        strScript.Append("v" + formID + ".submit();");

        strScript.Append("</script>");

        //Return the form and the script concatenated. (The order is important, Form then JavaScript)

        return strForm.ToString() + strScript.ToString();

    }

    /// <summary>

    /// POST data and Redirect to the specified url using the specified page.

    /// </summary>

    /// <param name="page">The page which will be the referrer page.</param>

    /// <param name="destinationUrl">The destination Url to which the post and redirection is occuring.</param>

    /// <param name="data">The data should be posted.</param>

    /// <Author>Samer Abu Rabie</Author>

    public static void RedirectAndPOST(Page page, string destinationUrl, NameValueCollection data)

    {

        //Prepare the Posting form

        string strForm = PreparePOSTForm(destinationUrl, data);

        //Add a literal control the specified page holding the Post Form, this is to submit the Posting form with the request.

        page.Controls.Add(new LiteralControl(strForm));

    }

}