Question

I’m trying to make a simple text editor that colors text in real time. I also must use DLL and Reflection for this.
I want to color the text while user typing. For that reason I have a checkbox. If it checked the text will be colored while user is typing (Real Time).

I’ve wrote a DLL file to do that.

Anyway, I’m very new to reflection thing.

• The question:

I would want to ask you guys for your professional advice whether what I’ve wrote can be called “using reflection” or not? and if it’s not, can point me what is wrong?

Here is my code (I’ve removed many things from it so the code will reflect the question but there might be leftovers)

using System;
using System.Drawing;
using System.Windows.Forms;
using System.IO;
using System.Diagnostics;
using System.Reflection;

namespace Editor
{
    public class MainForm : Form
    {
        //Declaration of Controls 
        private RichTextBox EditRichTextBox;
        private CheckBox chkBox;
        private int flag = 0;

        private Button[] PlugButton;
        public string[] PluginNames;
        private int NumofPlugins;

        public MainForm()
        {
            //Initialization of Controls
            this.EditRichTextBox = new RichTextBox();
            this.ErrorTextBox = new RichTextBox();
        this.chkBox = new CheckBox();

            //Form
            this.ClientSize = new Size(700, 500);
            this.Name = "MainForm";
            this.Text = "C# Editor";

            //EditRichTextBox
            this.EditRichTextBox.Location = new Point(20, 20);
            this.EditRichTextBox.Name = "EditRichTextBox";
            this.EditRichTextBox.Size = new Size(this.Width - 150, 300);
            this.EditRichTextBox.AcceptsTab = true;
            this.EditRichTextBox.Multiline = true;

            //Controls on the Form
        this.Controls.Add(this.ButtonCompilelib);
            this.Controls.Add(this.ButtonCompile);
            this.Controls.Add(this.ButtonRun);
            this.Controls.Add(this.EditRichTextBox);
            this.Controls.Add(this.ErrorTextBox);
        this.Controls.Add(this.chkBox);

        //CheckBox
        this.chkBox.Location = new Point(600,300);
            this.chkBox.Name = "chkBox";
            this.chkBox.Text = "Color";
        };

        //My checkbox handler
        this.chkBox.Click += (sender,e) =>
        {
            if(flag == 0)
            {
                flag = 1;
                MessageBox.Show("Coloring Text");
                }
            else 
                flag = 0;
        };

        //My TextBox handler
        this.EditRichTextBox.KeyPress += (sender,e) =>
        {
            try
            {
                string tmp = Environment.CurrentDirectory + "\\" + "mydll" + ".dll";            Assembly a = Assembly.LoadFrom(tmp);
                Type t = a.GetType("MyPlugIn.colorclass");
                MethodInfo mi = t.GetMethod("color");
                Object obj = Activator.CreateInstance(t);

                Object[] Params = new Object[5];
                Params[0] = EditRichTextBox.Text;
                Params[1] = EditRichTextBox.Handle;
                Params[2] = ErrorTextBox.Handle;
                Params[3] = EditRichTextBox;
                Params[4] = flag;
                mi.Invoke(obj, Params);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        };


        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.Run(new MainForm());
        }
    }
}

And this is the DLL file

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing;

namespace MyPlugIn
{
    public class colorclass
    {
        public void color(string Text, Object Hndl_Text, Object Hndl_Err, RichTextBox box,int flag)
        {
            if (flag == 1)
            {
                int start = box.TextLength;
                int end = box.TextLength;

                //Textbox may transform chars, so (end-start) != text.Length
                box.Select(start, end - start);
                {
                    box.SelectionColor = Color.Blue;
                }
                box.SelectionLength = 0; // clear
            }
        }
    }
}

Answer 1

Yes, your code uses Reflection. These lines are an example:

Type t = a.GetType("MyPlugIn.colorclass");
MethodInfo mi = t.GetMethod("color");
Object obj = Activator.CreateInstance(t);

Whether is the best approach or not, or whether it’s necessary for this task, it’s a different topic.