Добавьте файлы проекта.

demo26052026/UserControl2.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace demo26052026
+{
+    public partial class UserControl2 : UserControl
+    {
+        Form form { get; set; }
+        public UserControl2(Form s)
+        {
+            form = s;
+            InitializeComponent();
+            foreach (Control control in this.Controls)
+            {
+                control.Click += textBox5_Click;
+            }
+        }
+
+        private void textBox5_TextChanged(object sender, EventArgs e)
+        {
+
+        }
+
+        private void textBox5_Click(object sender, EventArgs e)
+        {
+            form.Hide();
+            Form4 form2 = new Form4(int.Parse(this.Name));
+            form2.ShowDialog();
+        }
+    }
+}