Способ преобразовать строку в имя элемента textBox1

private void Form1_Load(object sender, EventArgs e)
        {
            int number = 1;
            String text = "textBox" + number;
            TextBox tb = (TextBox)text;
            tb.Text = "HALLO";
        }

private void Form1_Load(object sender, EventArgs e)
        {
            int number = 2;
            String text = "textBox" + number;
            (Controls[text] as TextBox).Text = "newText";
 
        }

number ++;

tabPage1 = new System.Windows.Forms.TabPage();

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
 
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        Form fr = new Form();
        TabPage tb = new TabPage();
        TabControl ta = new TabControl();
        TextBox tt = new TextBox();
        public void Form1_Load(object sender, EventArgs e)
        {
     
            int number1 = 1;
            int number2 = 2;
            String text1 = "textBox" + number1;
            String text2 = "textBox" + number2;
            (this.Controls[text1] as TextBox).Text = "HALLO";
            int test = Convert.ToInt32((this.Controls[text1] as TextBox).Text);
            (this.Controls[text2] as TextBox).Text = String.Format("{0}", test);
        }
    }
}

(this.Controls[text1] as TextBox).Text = "1234";

this.tabPage1.Controls.Add(this.textBox2);
this.tabPage1.Controls.Add(this.textBox1);

            (this.tabPage1.Controls[text1] as TextBox).Text = "1234";
            int test = Convert.ToInt32((this.tabPage1.Controls[text1] as TextBox).Text);
            (this.tabPage1.Controls[text2] as TextBox).Text = String.Format("{0}", test);

Controls[tc]

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
 
namespace ClientCOM
{
    class ClassReadWriteForm
    {
                public byte ReadWriteForms(string tab_control, byte contr, string tab_page, byte pag, string text_box, byte box, out Int32 result_out, Int32 result_in, byte key_r_w)
        {
            result_out = 0;
            string tc = tab_control + contr;
            string tp = tab_page + pag;
 
            string tb = text_box + box;
                if (key_r_w == 0)
                {
                    (((Controls[tc] as TabControl).Controls[tp] as TabPage).Controls[tb] as TextBox).Text = Convert.ToString(result_in); //запись в форму
                }
                else if (key_r_w == 1)
                {
                    result_out = Convert.ToInt32((((Controls[tc] as TabControl).Controls[tp] as TabPage).Controls[tb] as TextBox).Text);  //чтение из формы
                }
            return 0;
        }
    }
}

namespace ClientCOM
{
    class ClassReadWriteForm
    {
        Form fr = new Form();
        public byte ReadWriteForms(string tab_control, byte contr, string tab_page, byte pag, string text_box, byte box, out Int32 result_out, Int32 result_in, byte key_r_w)
        {
            result_out = 0;
            string tc = tab_control + contr;
            string tp = tab_page + pag;
 
            string tb = text_box + box;
                if (key_r_w == 0)
                {
                    (((fr.Controls[tc] as TabControl).Controls[tp] as TabPage).Controls[tb] as TextBox).Text = Convert.ToString(result_in); //запись в форму
                }
                else if (key_r_w == 1)
                {
                    result_out = Convert.ToInt32((((fr.Controls[tc] as TabControl).Controls[tp] as TabPage).Controls[tb] as TextBox).Text);  //чтение из формы
                }
            return 0;
        }
    }
}

Form fr = new Form();

public partial class ClassReadWriteForm : Form

class InheritedForm : BaseForm

(((fr.Controls[tc] as TabControl).Controls[tp] as TabPage).Controls[tb] as TextBox).Text = Convert.ToString(result_in); //запись в форму