Save and Restore Form Position and Size

Question

In a WinForms 2.0 C# application, what is the typical method used for saving and restoring form position and size in an application?

Related, is it possible to add n

Answer 1

There is actually a real lack of a single, "just works" solution to this anywhere on the internet, so here's my own creation:

using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Windows.Forms;
using Microsoft.Win32;
using System.ComponentModel;
using System.Security.Cryptography;

namespace nedprod
{
    abstract public class WindowSettings
    {
        private Form form;

        public FormWindowState state;
        public Point location;
        public Size size;

        public WindowSettings(Form _form)
        {
            this.form = _form;
        }
        internal class MD5Sum
        {
            static MD5CryptoServiceProvider engine = new MD5CryptoServiceProvider();
            private byte[] sum = engine.ComputeHash(BitConverter.GetBytes(0));
            public MD5Sum() { }
            public MD5Sum(string s)
            {
                for (var i = 0; i < sum.Length; i++)
                    sum[i] = byte.Parse(s.Substring(i * 2, 2), System.Globalization.NumberStyles.HexNumber);
            }
            public void Add(byte[] data)
            {
                byte[] temp = new byte[sum.Length + data.Length];
                var i=0;
                for (; i < sum.Length; i++)
                    temp[i] = sum[i];
                for (; i < temp.Length; i++)
                    temp[i] = data[i - sum.Length];
                sum=engine.ComputeHash(temp);
            }
            public void Add(int data)
            {
                Add(BitConverter.GetBytes(data));
            }
            public void Add(string data)
            {
                Add(Encoding.UTF8.GetBytes(data));
            }
            public static bool operator ==(MD5Sum a, MD5Sum b)
            {
                if (a.sum == b.sum) return true;
                if (a.sum.Length != b.sum.Length) return false;
                for (var i = 0; i < a.sum.Length; i++)
                    if (a.sum[i] != b.sum[i]) return false;
                return true;
            }
            public static bool operator !=(MD5Sum a, MD5Sum b)
            {
                return !(a == b);
            }
            public override bool Equals(object obj)
            {
                try
                {
                    return (bool)(this == (MD5Sum)obj);
                }
                catch
                {
                    return false;
                }
            }
            public override int GetHashCode()
            {
                return ToString().GetHashCode();
            }
            public override string ToString()
            {
                StringBuilder sb = new StringBuilder();
                for (var i = 0; i < sum.Length; i++)
                    sb.Append(sum[i].ToString("x2"));
                return sb.ToString();
            }
        }
        private MD5Sum screenconfig()
        {
            MD5Sum md5=new MD5Sum();
            md5.Add(Screen.AllScreens.Length); // Hash the number of screens
            for(var i=0; i

This implementation stores the position and size of a form in HKCU/Software///Window State/

. It won't restore settings if the monitor configuration changes as so to prevent windows being restored off screen.

Obviously this can't handle multiple instances of the same form. I also specifically disabled restoring minimised but that's an easy fix of the source.

The above is designed to be dropped into its own .cs file and never touched again. You have to instantiate a local namespace copy like this (in Program.cs or your plugin main .cs file or wherever):

namespace 
{
    public class WindowSettings : nedprod.WindowSettings
    {
        public WindowSettings(Form form) : base(form) { }
        protected override string CompanyId() { return ""; }
        protected override string AppId() { return ""; }
    }
    ....

Now you have a non-abstract instantiation in the main namespace. So, to use, add this to the forms you want saved and restored:

    private void IssuesForm_FormClosing(object sender, FormClosingEventArgs e)
    {
        new WindowSettings(this).save();
    }

    private void IssuesForm_Load(object sender, EventArgs e)
    {
        new WindowSettings(this).load();
    }

Obviously feel free to customise to your own purposes. No warranty is expressed or implied. Use at your own risk - I disclaim any copyright.

Niall