Visual Studio C #, Loop

Question

Visual Studio C #

I made a calculator, and now I have to make a calculator memory (event).

There are 4 components other than the calculator: one Textbox for the answer of the calculator, two Buttons for "M" and "M+", and one Lable to display the answer again.

When the user clicks the “M” button, the contents of the Answer TextBox should be copied to a memory variable. Also make it so that when the user moves the mouse over the label, the value in the memory variable will appear in this label, and then disappear, when the mouse moves away from the label. Also add one more button, an “M+” button. When the user clicks this button, the contents of the Results box will be added to Memory. You will need to use a Global Variable to store this data.

My problem is that the label doesn't appear when the mouse over the label, and also it doens't disappear when the mouse leave the label. How can I fix it?

And also, is this way the right way to use the Global variable?

Below is my code (I just put the code for "M" and "M+" buttons, not the code for the calculator).

    private String ans;
    private Double answer;
    private Double answerPlus;

    private void btnM_Click(object sender, EventArgs e)
    {
        ans = txtDisplay.Text;
        answer = double.Parse(ans);
        lblblank.Text = answer.ToString();
    }

    private void lblblank_MouseEnter(object sender, EventArgs e)
    {           
        lblblank.Show();           
        lblblank.Text = answer.ToString();
    }

    private void lblblank_MouseLeave(object sender, EventArgs e)
    {
        lblblank.Hide();
    }

    private void btnMplus_Click(object sender, EventArgs e)
    {
        answerPlus = answer + double.Parse(ans);
        lblblank.Text = answerPlus.ToString();
    }

Answer 1

Storing variables
The way you store your values is fine.

Events
Once you call .Hide() the next MouseEnter/MouseLeave-event will not be triggered anymore. What you could do is to take a panel, or any layout element as a wrapper/parent-element for the label and then adjust your event-callbacks to something like that:

 private void panel_MouseEnter(object sender, EventArgs e)
 {           
     lblblank.Show();           
     lblblank.Text = answer.ToString();
 }

 private void panel_MouseLeave(object sender, EventArgs e)
 {
     lblblank.Hide();
 }

Edit
~~~

What does it mean that any layout element as a parent-element for the label? Could you explain more?

What I meant was to just create a new panel (or layout-element) and put the label into it as a child. See the picture below:

If you set that up correctly, the code snippet I posted above will work just fine. This solution does not prevent the MouseLeave event from triggering when your mouse enters the label. Therefore you could use an alternative solution using the MouseMove event.

Alternative

using System;
using System.Windows.Forms;
using System.Drawing;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            this.InitializeComponent();

            // Subscribe to the MouseMove event
            this.panel.MouseMove += this.panel_MouseMove;
        }

        private void panel_MouseMove(object sender, MouseEventArgs e)
        {
            // Checks if current mouse position is within the panel
            if (this.panel.Bounds.Contains(new Point(e.X, e.Y)))
            {
                // Current mouse position within the panel
                this.label.Show();
                return;
            }

            // Current mouse position outside the panel
            this.label.Hide();
        }
    }
}