Add project files.

Metoder/Form1.cs

@@ -0,0 +1,93 @@
+using System;
+using System.Net.Security;
+using System.Reflection;
+using static System.Net.Mime.MediaTypeNames;
+
+namespace Metoder
+{
+    public partial class Form1 : Form
+    {
+        public Form1()
+        {
+            InitializeComponent();
+        }
+
+        private void btn_find_Click(object sender, EventArgs e)
+        {
+            string searchWord = txtbx_find.Text;
+            Highlight(searchWord);
+        }
+
+        private void btn_clear_Click(object sender, EventArgs e)
+        {
+            lbl_found.Visible = false;
+        }
+
+        void UpdateFindResult(int foundCount)
+        {
+            lbl_found.Visible = true;
+            string suffix;
+
+            // correct grammar
+            if (foundCount == 1)
+                suffix = " item found";
+            else
+                suffix = " items found";
+
+            lbl_found.Text = foundCount.ToString() + suffix;
+        }
+
+        (int start, int length) FindTextIndex(string text, int startIndex)
+        {
+            int start = (text.IndexOf(text, startIndex, StringComparison.OrdinalIgnoreCase));
+            if (start == -1) return (-1, 0);
+
+            return (start, text.Length);
+        }
+
+        void Highlight(string word)
+        {
+            if (word == "") return; // avoid errors, infinite loop
+
+            RichTextBox richTextBox = txtbx_text;
+            string text = richTextBox.Text;
+
+            // reset old highlight
+            richTextBox.SelectAll();
+            richTextBox.SelectionBackColor = richTextBox.BackColor;
+
+            int found = 0;
+            int caret = richTextBox.SelectionStart; // set cursor
+
+            var words = GetWords();
+            int index = 0;
+
+            while ((index = text.IndexOf(word, index, StringComparison.OrdinalIgnoreCase)) != -1)
+            {
+                richTextBox.Select(index, word.Length); // select word
+                richTextBox.SelectionBackColor = Color.LightBlue;
+                found++; // count found
+                index = index + word.Length; // offset (ignore word next loop)
+            }
+
+            // reset cursor
+            richTextBox.Select(caret, 0);
+
+            // update find label
+            UpdateFindResult(found);
+        }
+
+        List<string> GetWords() // get list of words separated by spaces
+        {
+            string text = txtbx_text.Text;
+            string[] words = text.Split((char[])null, StringSplitOptions.RemoveEmptyEntries);
+
+            return words.ToList();
+        }
+
+        private void btn_replace_Click(object sender, EventArgs e)
+        {
+
+        }
+    }
+}