What is the difference between these three ways to clear a Textbox?

Question

I am bit confused between the below three ways to clear the contents of a textbox. I am working with WPF and found All are working, but I am unable to find the difference.

Answer 1

If not going really deep:

Clear: remove content from TextBox and may be delete resources allocated with it

    public void Clear()
    {
      using (this.TextSelectionInternal.DeclareChangeBlock())
      {
        this.TextContainer.DeleteContentInternal(this.TextContainer.Start, this.TextContainer.End);
        this.TextSelectionInternal.Select(this.TextContainer.Start, this.TextContainer.Start);
      }
    }

Assigning empty string (because string.Empty and "" are equal) to Text property just assign empty string to attached property TextBox.TextProperty:

public string Text
{
  get
  {
    return (string) this.GetValue(TextBox.TextProperty);
  }
  set
  {
    this.SetValue(TextBox.TextProperty, (object) value);
  }
}