Listing of PostData.cs
using System;
using System.Web;
using System.Collections;
using System.Collections.Generic;

/// <summary>
/// Class for retrieving post variables
/// </summary>

//-----------------------------------------------------------------------
//  Class which holds one individual post variable
//-----------------------------------------------------------------------
public class PostDataEntry {
    public string sqlName;          // name used in sql query
    public int type;                // 0 = integer
    public int update;              // 1 means include in update

    public string qValue;           // for sql queries
    public int iValue;              // integer value
    private string _value;          // string value, masked below

    //-------------------------------------------------------------------
    //  set the three types of values
    //-------------------------------------------------------------------
    public string sValue {
        get {
            return _value;
        }
        set {
            _value = value;
            try {
                iValue = Convert.ToInt32(value);
            } catch {
                iValue = 0;
            }
            if (type > 0)
                qValue = "'" + Utility.encodeString(value) + "'";
            else
                qValue = value;
        }
    }

    //-------------------------------------------------------------------
    //  constructor
    //-------------------------------------------------------------------
    public PostDataEntry(int type, string name, string sqlName, string value) {
        this.type = type;
        this.sqlName = sqlName;
        this.update = 1;
        this.sValue = value;
    }
}

//-----------------------------------------------------------------------
//  Class for holding the sql variables
//-----------------------------------------------------------------------
public class PostData {
    private List<PostDataEntry> _pv = new List<PostDataEntry>();
    private List<string> _name = new List<string>();
    private HttpContext _context;

    //-------------------------------------------------------------------
    //  constructor
    //-------------------------------------------------------------------
    public PostData(HttpContext context) {
        _context = context;
    }

    //-------------------------------------------------------------------
    //  add a new element
    //-------------------------------------------------------------------
    public void Add(int type, string name) {
        init(type, name, name);
    }

    public void Add(int type, string name, string sqlName) {
        init(type, name, sqlName);
    }

    //-------------------------------------------------------------------
    //  does the real work for the above two routines
    //-------------------------------------------------------------------
    private void init(int type, string name, string sqlName) {
        string value;
        try {
            value = _context.Request[name].ToString().Trim();
        } catch {
            value = type > 0 ? "" : "0";
        }
        _pv.Add(new PostDataEntry(type, name, sqlName, value));
        _name.Add(name);
    }

    //-------------------------------------------------------------------
    //  the default get is to return the SQL form of the variable
    //  set transfers the string value
    //-------------------------------------------------------------------
    public string this[int i] {
        get {
            return _pv[i].qValue;
        }
        set {
            _pv[i].sValue = value;
        }
    }
    public string this[string name] {
        get {
            int i = _name.IndexOf(name);
            return _pv[i].qValue;
        }
        set {
            int i = _name.IndexOf(name);
            _pv[i].sValue = value;
        }
    }

    //-------------------------------------------------------------------
    //  return the size of the array
    //-------------------------------------------------------------------
    public int Length {
        get {
            return _name.Count;
        }
    }

    //-------------------------------------------------------------------
    //  returns the index of a given variable name
    //-------------------------------------------------------------------
    public int IndexOf(string name) {
        return _name.IndexOf(name);
    }

    //-------------------------------------------------------------------
    //  sets the value of the update property
    //-------------------------------------------------------------------
    public void Update(string name, int value) {
        int i = _name.IndexOf(name);
        _pv[i].update = value;
    }

    //-------------------------------------------------------------------
    //  get the value as a string (without any extra quotes)
    //-------------------------------------------------------------------
    public string Value(string name) {
        int i = _name.IndexOf(name);
        return _pv[i].sValue;
    }

    public string Value(int i) {
        return _pv[i].sValue;
    }

    //-------------------------------------------------------------------
    //  return the name for a particular index
    //-------------------------------------------------------------------
    public string Name(int i) {
        return _name[i];
    }

    //-------------------------------------------------------------------
    //  The next three methods are used for generating sql.
    //  Names return a comma separated list of names for an insert statement
    //-------------------------------------------------------------------
    public string Names() {
        string s = "";
        for (int i = 0; i < _name.Count; i++) {
            if (_pv[i].update == 1) {
                if (s != "") s += ",";
                s += _pv[i].sqlName;
            }
        }
        return s;
    }

    //-------------------------------------------------------------------
    //  Value return a comma separated list of values
    //-------------------------------------------------------------------
    public string Values() {
        string s = "";
        for (int i = 0; i < _name.Count; i++) {
            if (_pv[i].update == 1) {
                if (s != "") s += ",";
                s += _pv[i].qValue;
            }
        }
        return s;
    }

    //-------------------------------------------------------------------
    //  NameValues return a comma separated list of name = value
    //-------------------------------------------------------------------
    public string NameValues() {
        string s = "";
        for (int i = 0; i < _name.Count; i++) {
            if (_pv[i].update == 1) {
                if (s != "") s += ",";
                s += NameValue(i);
            }
        }
        return s;
    }
    //-------------------------------------------------------------------
    //  NameValue return a comma separated pair of name = value
    //-------------------------------------------------------------------
    public string NameValue(int i) {
        return _pv[i].sqlName + "=" + _pv[i].qValue;
    }
}