title: After "." the value entered must replace "00" with two digits only in the textbox
body: <p>May be My Question is not seems like a good one but here is the Description:
  I am creating an application in this in a form i have a textbox which is taking input from user here is my Code</p>
  
  <pre><code>private void Form1_Load(object sender, EventArgs e)
  {
      textBox1.Text = string.Format("{0:0.##}", "0.00");
  }
  </code></pre>
  
  <p>this will show value in textbox at pageload:<strong>0.00</strong>
  Now after this if i click on backspace button of keyboard then </p>
  
  <pre><code>if (e.KeyChar.ToString() == ".")
  {
      e.Handled = true;
      int b = textBox1.Text.LastIndexOf("00");
      textBox1.SelectionStart = b;
  }
  else
  {
      string abc = "0";
      string a = textBox1.Text.TrimStart(abc.ToCharArray());
      textBox1.Text = a;
  }
  </code></pre>
  
  <p>this code will lead me to here the textbox has now: <strong>.00</strong> only
  but after this when i enter some value then it will take values as;
  2334.3423424
  but i want to do like
  2334.34
  it means value should replace <strong>.00</strong> only and user cant enter value after that.</p>