C#

1. Easiest but normally worst
   
   Static properties/variables as you mentioned. If using this, as they will need to be either internal or public I would strongly suggest properties with a private backing field.
2. Next best
   
   A singleton class instance. See here[^] for a good tutorial by one of the C# gods.
3. Normally the best, but can be complex to implement depending on class hierachys
   
   Let the parent form decide if the delete should be allowed and perform it. The children simply request the action and pass any required data via an event.

using System.Windows.Forms;

namespace CpDelegateSample
{
    public partial class FormMain : Form
    {
        private bool toggle;

        public FormMain()
        {
            InitializeComponent();
            toggle = false;
            FormSub formSub = new FormSub();
            formSub.DeleteRequest += new FormSub.DeleteRequestEventHandler(formSub_DeleteRequest);
            formSub.Show();
        }

        private bool formSub_DeleteRequest(string data)
        {
            // If OK, do delete and return true; otherwise, return false
            bool result = toggle;
            string message = result ? "Allowing" : "Denying";
            MessageBox.Show(string.Format("{0} {1}", message, data));
            toggle = !toggle;
            return result;
        }
    }
}

using System;
using System.Windows.Forms;

namespace CpDelegateSample
{
    public partial class FormSub : Form
    {
        public delegate bool DeleteRequestEventHandler(string data);

        public event DeleteRequestEventHandler DeleteRequest;

        public FormSub()
        {
            InitializeComponent();
            Click += new EventHandler(FormSub_Click);
        }

        void FormSub_Click(object sender, EventArgs e)
        {

            OnDeleteRequest("ABC");
            OnDeleteRequest("DEF");
        }

        protected virtual void OnDeleteRequest(string data)
        {
            DeleteRequestEventHandler eh = DeleteRequest;
            if (eh != null)
            {
                bool result = eh(data);
                string message = result ? "Allowed" : "Denied";
                MessageBox.Show(string.Format("{0} {1}", message, data));
            }
        }
    }
}

Ennis Ray Lynch, Jr. wrote:

Learn something new every day.

private void dataGridView1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
{
}

T M Gray wrote:

Ahh he used the wrong control name

byte[] sResult = sha.ComputeHash(StrToByteArray(sName + sPassword));
byte[] sSessionResult =sha.ComputeHash(StrToByteArray(sSessionID));
byte[] returnResult = bew byte[sResult.length + sSessionResult.length];
Array.Copy(sResult, returnResult , 0, sResult.length);
Array.Copy(sSessionResult, returnResult , sResult.length, sSessionResult.length);
sResult = returnResult ;