private void WeightInputTextBox_Leave(object sender, EventArgs e)
 {
     if (System.Text.RegularExpressions.Regex.IsMatch(WeightInputTextBox.Text, "[^0-9-(.)]"))
     {
         WeightInputTextBox.Focus();
         MessageBox.Show("Weight should be number Only!");
     }
 }
 /// <summary>
 /// This method will clear all user input and selections
 /// </summary>
 private void ReturnToDefault()
 {
     HeightInputTextBox.Clear();
     WeightInputTextBox.Clear();
     BMI_ResultTextBox.Clear();
     ResultMeaningTextBox.Clear();
     _inchesInputTextBoxSelected = false;
     _weightInputTextBoxSelected = false;
     BMI_ResultTextBox.ReadOnly  = true;
     CalculateButton.Enabled     = false;
 }