Validation Rules for fields / Reglas de validación para campos

Sometimes we need to be sure that certain data is entered to each field of our forms, web pages, etc. So we need to specify clearly what type of information can be typed and why. Take a look to this table, (you must adapt for your specific language), the explanation column can help you to document the field requirements.

Algunas veces necesitamos estar seguros que ciertos datos son ingresados para cada campo de nuestros formularios, páginas web, etc. Así que necesitamos especificar claramente que tipo de información puede ser digitada y por qué. Mire la siguiente tabla, (debe adaptarla a su propio lenguaje), la columna explicación puede ayudarle a documentar los requerimientos de campo.

To do this … Validation Rule for Fields Explanation
Accept letters (a – z) only Is Null OR Not Like “*[!a-z]*” Any character outside the range A to Z is rejected. (Case insensitive.)
Accept digits (0 – 9) only Is Null OR Not Like “*[!0-9]*” Any character outside the range 0 to 9 is rejected. (Decimal point and negative sign rejected.)
Letters and spaces only Is Null Or Not Like “*[!a-z OR “” “”]*” Punctuation and digits rejected.
Digits and letters only Is Null OR Not Like “*[!((a-z) or (0-9))]*” Accepts A to Z and 0 to 9, but no punctuation or other characters.
Exactly 8 characters Is Null OR Like “????????” The question mark stands for one character.
Exactly 4 digits Is Null OR Between 1000 And 9999 For Number fields.
Is Null OR Like “####” For Text fields.
Positive numbers only Is Null OR >= 0 Remove the “=” if zero is not allowed either.
No more than 100% Is Null OR Between -1 And 1 100% is 1. Use 0 instead of -1 if negative percentages are not allowed.
Not a future date Is Null OR <= Date()
Email address Is Null OR ((Like “*?@?*.?*”) AND
(Not Like “*[ ,;]*”))
Requires at least one character, @, at least one character, dot, at least one character. Space, comma, and semicolon are not permitted.
You must fill in Field1 Not Null Same as setting the field’s Required property, but lets you create a custom message (in the Validation Text property.)
Limit to specific choices Is Null OR “M” Or “F” It is better to use a lookup table for the list, but this may be useful for simple choices such as Male/Female.
Is Null OR IN (1, 2, 4, 8) The IN operator may be simpler than several ORs.
Yes/No/Null field Is Null OR 0 or -1 The Yes/No field in Access does not support Null as other databases do. To simulate a real Yes/No/Null data type, use a Number field (size Integer) with this rule. (Access uses 0 for False, and -1 for True.)


Information extracted from: there you can find more specifications.




Cerrando aplicaciones Windows Phone 7 – 8

He estado bajando y verificando muchas aplicaciones en Windows Phone y la mayoría tiene problemas con la salida. Es decir ingresas a la aplicación, navegas sobre las diferentes opciones y cuando deseas salir, das tap en el botón “Atrás”, y por cuantas veces hayas navegado te toca seguir dando tap y tap… bastante aburrido. Sería mejor que llegando al menú principal, dar un tap en “Atrás” y que se pueda cerrar la aplicación. Para lograr esto debes adicionar el siguiente código en OnBackKeyPress: (código tomado de la aplicación Mimensaje que sirve para enviar hasta 2 mensajes preconfigurados.)

protectedoverridevoid OnBackKeyPress(System.ComponentModel.CancelEventArgs e)   {

MessageBoxResult res = MessageBox.Show(“¿Seguro Desea Salir de MiMensaje?”, “Por favor confirme:”, MessageBoxButton.OKCancel);

if (res == MessageBoxResult.OK)     {

while (NavigationService.BackStack.Any())  NavigationService.RemoveBackEntry();

this.IsHitTestVisible = this.IsEnabled = false;

if (this.ApplicationBar != null)

foreach (var item inthis.ApplicationBar.Buttons.OfType<ApplicationBarIconButton>())

item.IsEnabled = false



{     e.Cancel = true}