Private Sub TextBox1_Validating(ByVal Sender As Object, _
   ByVal e As System.ComponentModel.CancelEventArgs) Handles _
   TextBox1.Validating
      If Not IsNumeric(TextBox1.Text) Then
         ErrorProvider1.SetError(TextBox1, "Not a numeric value.")
      Else
         ' Clear the error.
         ErrorProvider1.SetError(TextBox1, "")
      End If
End Sub

protected void textBox1_Validating (object sender,
   System.ComponentModel.CancelEventArgs e)
{
   try
   {
      int x = Int32.Parse(textBox1.Text);
      errorProvider1.SetError(textBox1, "");
   }
   catch (Exception e)
   {
      errorProvider1.SetError(textBox1, "Not an integer value.");
   }
}

protected void textBox1_Validating(Object sender, CancelEventArgs e) 
{
   try 
   {
      int x = Int32.Parse(textBox1.get_Text());
      errorProvider1.SetError(textBox1, "");
   }
   catch(Exception exp)
   {
      errorProvider1.SetError(textBox1, "Not an integer value.");
   }
}

private:
   System::Void textBox1_Validating(System::Object ^  sender,
      System::ComponentModel::CancelEventArgs ^  e)
   {
      try
      {
         int x = Int32::Parse(textBox1->Text);
         errorProvider1->SetError(textBox1, "");
      }
      catch (System::Exception ^ ex)
      {
         errorProvider1->SetError(textBox1, "Not an integer value.");
      }
   }

this.textBox1.Validating += new
System.ComponentModel.CancelEventHandler(this.textBox1_Validating);

this->textBox1->Validating += gcnew
   System::ComponentModel::CancelEventHandler
   (this, &Form1::textBox1_Validating);