title: FormatException when converting richtextbox string to int
body: <p>This is the whole code:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="false" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>using System;
  using System.Collections.Generic;
  using System.Drawing;
  using System.Windows.Forms;
  
  namespace Calculator
  {
   public partial class MainForm : Form
   {
    public MainForm()
    {
     InitializeComponent();
     richTextBox1.ReadOnly = true;
    }
    
    //inputs
    void Button1Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("1");
    }
    void Button2Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("2");
    }
    void Button3Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("3");
    }
    void Button6Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("4");
    }
    void Button5Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("5");
    }
    void Button4Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("6");
    }
    void Button9Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("7");
    }
    void Button8Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("8");
    }
    void Button7Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("9");
    }
    void Button10Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("0");
    }
    void Button14Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("+");
    }
    void Button13Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("-");
    }
    void Button12Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("X");
    }
    void Button11Click(object sender, EventArgs e)
    {
     richTextBox1.AppendText("/");
    }
    void Button15Click(object sender, EventArgs e)
    {
     String fetch = richTextBox1.Text;
     String convert = fetch.Replace('X', '*');
     try
     {
      int equ = Int32.Parse(convert);
     }
     catch (FormatException exe)
     {
      MessageBox.Show(exe.Message);
     }
    }
    
   }
  }</code></pre>
  </div>
  </div>
  </p>
  
  <p>This is the part that's throwing the exception:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>void Button15Click(object sender, EventArgs e)
    {
     String fetch = richTextBox1.Text;
     String convert = fetch.Replace('X', '*');
     try
     {
      int equ = Int32.Parse(convert);
     }
     catch (FormatException exe)
     {
      MessageBox.Show(exe.Message);
     }
    }</code></pre>
  </div>
  </div>
  </p>
  
  <p>For some reason, Int32.parse can't change the "convert" string to an integer, throwing "Input string was not in a correct format" instead. I can't figure out why. I've tried using Convert.Int32() too, but it still throws the same exception.</p>