title: How to validate that the entry of a number is not with "0" in C #
body: <p>I have a control of type <code>&lt;Entry&gt;</code> in which I don't want the user to enter values ​​that start with "0", for example...</p>
  
  <blockquote>
    <p>0</p>
    
    <p>01</p>
    
    <p>00</p>
    
    <p>00010</p>
  </blockquote>
  
  <p>But if I want to enter values ​​that contain "0" in the form of natural numbers, for example ...</p>
  
  <blockquote>
    <p>10</p>
    
    <p>2010</p>
    
    <p>200000</p>
  </blockquote>
  
  <p><code>MyView.XAML</code>:</p>
  
  <pre><code>&lt;Entry
        HorizontalOptions="FillAndExpand"
        Placeholder="Cantidad"
        Keyboard="Numeric"
        MaxLength="9"
        Text="{Binding CantidadContenedor}"&gt;&lt;/Entry&gt;
  </code></pre>
  
  <p><code>MyViewModel.CS</code>:</p>
  
  <pre><code>   string cantidadContenedor;
  
     public string CantidadContenedor
          {
              get
              {
                  return  cantidadContenedor;
              }
              set
              {
                  if (cantidadContenedor != value)
                  {
                      cantidadContenedor = value;
                      PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(CantidadContenedor)));
                  }
              }
          }
  </code></pre>
  
  <p>How can I add this validation once I capture the value of the <code>Entry</code>?</p>
  
  <p>Can I occupy the <code>TryParse</code> Property being a <code>Container Quantity</code> of type <code>string</code>?</p>
  
  <p>Any help for me?</p>