I want to use a regex validator to ensure that a certain string variable contains the substring "www.youtube.com/watch?v=", how would I do this?
[RegularExpression()]
[Required(ErrorMessage = "Youtube link is Required")]
[StringLength(100, ErrorMessage="Youtube link cannot exceed 50 characters")]
public string YoutubeLink { get; set; }
if (YoutubeLink.Contains("www.youtube.com/watch?v="))
{
//...
}
http://msdn.microsoft.com/en-us/library/dy85x1sa.aspx
To use the RegularExpression attribute, you must specify the regex to use :
[RegularExpression("www\\.youtube\\.com/watch\\?v=", ErrorMessage = "Link is incorrect")]
public string YoutubeLink { get; set; }
http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.regularexpressionattribute.aspx
I think what you might want is to check for any type of URL beginning. In that case, you would use #"^(http://)?(www\.)?youtube\.com/watch\?v=" as the regex string.
See an example of what this would match
Maybe much easier to use something like (Python):
ytlink = 'www.youtube.com/watch?v='
if(ytlink in yourfrase):
doYourLogic()
else:
smthElse()
Please correct me if I understood your question wrong.
Related
I'm trying to use the "RegularExpression" DataAnnotation validaiton in my model. My problem is even for the valid input I provide for the field containing the validation, the regex doesn't match and it fails.
I try to test the same valid input with the regex in a stand-alone console app and I find it gets through.
My point is, when regex is being used in dataannotation as validation, it considers all input as bad input. What am I missing here?
My regex is for checking comma-seperated email IDs. Here is my model:
public partial class BuildModel
{
public Int64 ConfigID { get; set; }
[Required(ErrorMessage = "Please select a stream!")]
public String Name{ get; set; }
[RegularExpression(#"^(([a-zA-Z0-9_\-\.]+)#((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)(\s*(;|,)\s*|\s*$))", ErrorMessage = "Please enter valid email IDs separated by commas")]
public string EmailIDs { get; set; }
public bool IsActive { get; set; }
}
Note: The "Required" data-annotation validation works just fine. It is just the Regex one, that won't work!
As far as i understand you just have problem within your Regex.
To validate emails separated by comma you can use this regex:
^( *[\w+-.%]+#[\w-.]+\.[A-Za-z]{2,4}( *, *)? *)+$
Check in in here.
You must the jquery.validate.min.js and jquery.validate.unobtrusive.min.js in your page without these libraries required annotation would not works.
I am trying to write a regular expression that replaces a data annotation adding more paramter to it.
For example,
Given this property
[DataMember(Name = "users")]
public List<User> Users { get; set; }
I would like to change it to
[DataMember(Name = "users"), XmlNode("users")]
public List<User> Users { get; set; }
Any idea how to achieve this?
search with this regex:
\[DataMember\(Name = \"(.*)\"\)\]
and replace by this one:
\[DataMember\(Name = "$1"\), XmlNode\("$1"\)\]
regex 101 link
I am using the regular expression for the Password field. Includes alpha-numeric string and md5.
[Required(AllowEmptyStrings = true)]
[RegularExpression(#"^(((?=.*\d)(?=.*[a-zA-Z]).{6,20})|([0-9a-f]{32}))$")]
[Display(Name = "Password")]
public string Password { get; set; }
And, I'd leave the field empty password. But ValidationMessage shows "This field is required."
message.Even if delete Required, it still gives the message.
Friends, how can I fix it?
Removing the Required attribute worked for me for server-side validation.
I've never used asp.net, and know nothing about it. However, 10 seconds on google tells me:
Make it nullable ( public string? Passsword { get; set; } )
We manage several ASP.NET MVC client web sites, which all use a data annotation like the following to validate customer email addresses (I haven't included the regex here, for readability):
[Required(ErrorMessage="Email is required")]
[RegularExpression(#"MYREGEX", ErrorMessage = "Email address is not valid")]
public string Email { get; set; }
What I would like to do is to centralise this regular expression, so that if we make a change to it, all of the sites immediately pick it up and we don't have to manually change it in each one.
The problem is that the regex argument of the data annotation must be a constant, so I cannot assign a value I've retrieved from a config file or database at runtime (which was my first thought).
Can anyone help me with a clever solution to this—or failing that, an alternative approach which will work to achieve the same goal? Or does this just require us to write a specialist custom validation attribute which will accept non-constant values?
The easiest way is to write a custom ValidationAttribute that inherits from RegularExpressionAttribute, so something like:
public class EmailAttribute : RegularExpressionAttribute
{
public EmailAttribute()
: base(GetRegex())
{ }
private static string GetRegex()
{
// TODO: Go off and get your RegEx here
return #"^[\w-]+(\.[\w-]+)*#([a-z0-9-]+(\.[a-z0-9-]+)*?\.[a-z]{2,6}|(\d{1,3}\.){3}\d{1,3})(:\d{4})?$";
}
}
That way, you still maintain use of the built in Regex validation but you can customise it. You'd just simply use it like:
[Email(ErrorMessage = "Please use a valid email address")]
Lastly, to get to client side validation to work, you would simply add the following in your Application_Start method within Global.asax, to tell MVC to use the normal regular expression validation for this validator:
DataAnnotationsModelValidatorProvider.RegisterAdapter(typeof(EmailAttribute), typeof(RegularExpressionAttributeAdapter));
Checkout ScotGu's [Email] attribute (Step 4: Creating a Custom [Email] Validation Attribute).
Do you really want to put the regex in database/config file, or do you just want to centralise them? If you just want to put the regex together, you can just define and use constants like
public class ValidationRegularExpressions {
public const string Regex1 = "...";
public const string Regex2 = "...";
}
Maybe you want to manage the regexes in external files, you can write a MSBuild task to do the replacement when you build for production.
If you REALLY want to change the validation regex at runtime, define your own ValidationAttribute, like
[RegexByKey("MyKey", ErrorMessage = "Email address is not valid")]
public string Email { get; set; }
It's just a piece of code to write:
public class RegexByKeyAttribute : ValidationAttribute {
public RegexByKey(string key) {
...
}
// override some methods
public override bool IsValid(object value) {
...
}
}
Or even just:
public class RegexByKeyAttribute : RegularExpressionAttribute {
public RegexByKey(string key) : base(LoadRegex(key)) { }
// Be careful to cache the regex is this operation is expensive.
private static string LoadRegex(string key) { ... }
}
Hope it's helpful: http://msdn.microsoft.com/en-us/library/cc668224.aspx
Why not just write you own ValidationAttribute?
http://msdn.microsoft.com/en-us/library/system.componentmodel.dataannotations.validationattribute.aspx
Then you can configure that thing to pull the regex from a registry setting... config file... database... etc... etc..
How to: Customize Data Field Validation in the Data Model Using Custom
I have a simple view model class for MVC2 that has a MagicItem property:
public class VoodooViewModel {
[Required(AllowEmptyStrings = false,
ErrorMessage = "The Magic Item is required")]
[RegularExpression(#"^[^-]*$",
ErrorMessage = "Hyphens are not allowed in Magic Items.")]
public string MajorModel { get; set; }
}
I am simply trying to disallow hyphens in this property, but for the life of me I can't get it to work. Can anyone see what I'm doing wrong (the RequiredAttribute is working fine)?
To my eyes, the regex I have says "from the beginning of the string to the end, match anything that isn't a hyphen". I have tested this in the Regex tester here, and it works - but not in my code. I can't get the error to show no matter how many hyphens I put in it.
Like a tool, I forgot to check in the controller's action method to see if the ModelState was valid or not:
public ActionResult UberController(VoodooViewModel vvm)
{
if (!ModelState.IsValid) return View(vvm); //turns out this line is important
(...yaddayaddayadda...)
}
Thanks to Darin for pointing me in the right direction.