I have a custom web config class. I want to add RegexStringValidator as an attribute to a web config property like:
[ConfigurationProperty("siteDomainName", DefaultValue = "")]
[RegexStringValidator(#"^([a-zA-Z0-9_-]*(?:\.[a-zA-Z0-9_-]*)+):?([0-9]+)?/?")]
public string SiteDomainName
{
get
{
return (string) this["siteDomainName"];
}
set
{
this["siteDomainName"] = value;
}
}
The error i am getting is :
The value does not conform to the validation regex string
'^([a-zA-Z0-9_-]*(?:.[a-zA-Z0-9_-]*)+):?([0-9]+)?/?'.
Even if the value supplied is correct and matches the Regex.
What is the problem with this??
Like ronen said in his comment, your default value should also match the regular expression. See this answer for example: https://stackoverflow.com/a/5313223/4830. The reason is that the default value is also evaluated and validated, even when you set a value in your web.config file.
Something like this should work (default value validates, and property is required so it should never actually use the default value in practice):
[ConfigurationProperty("siteDomainName", DefaultValue="www.example.com", IsRequired=True)]
[RegexStringValidator(#"^([a-zA-Z0-9_-]*(?:\.[a-zA-Z0-9_-]*)+):?([0-9]+)?/?")]
public string SiteDomainName
...
In case you don't want a default value, you could change the regular expression to accept the empty string, by making the whole value basically optional:
[ConfigurationProperty("siteDomainName", IsRequired=False)]
[RegexStringValidator(#"^(([a-zA-Z0-9_-]*(?:\.[a-zA-Z0-9_-]*)+):?([0-9]+)?/?)?$")]
public string SiteDomainName
...
Notice that the use of IsRequired in both code examples, use the one that best fits your needs. Be aware that de default value is always going to be validated.
Related
I have a view model containing a DateTime property, for which I want to provide a text box using using a custom format (only month and year, "MM.YYYY"):
public class MyModel {
public DateTime? DateField {get; set;}
}
Formatting the value for the TextBox is easy (using the format string). I also have implemented a custom model binder to do the conversion and this works fine.
I still have a problem with client side validation: I can implement a custom validator deriving from ValidationAttribute which implements IClientValidatable and set up the corresponding jquery.validate adapters etc.
But MVC still adds the "default" validation attribute data-val-date (in addition to my custom validation attribute data-val-monthyeardate) to the input field, so the default check still applies and the input "MM.YYYY" is rejected.
Is there any way to suppress the default client side validation for a data type and replace it with a custom one (instead of "adding" the custom one)?
Since the framework doesn't let you override the real type with some custom attribute or even override the ModelMetadataProvider for specific types, you'll have to register your own global ModelMetadataProvider that fools the validator to think it's actually a string.
Something like:
public class MyModelMetadataProvider : DataAnnotationsModelMetadataProvider
{
protected override ModelMetadata CreateMetadata(IEnumerable<Attribute> attributes, Type containerType, Func<object> modelAccessor, Type modelType, string propertyName)
{
if (attributes.OfType<ExcludeCharAttribute>().Any())
modelType = typeof (String);
return base.CreateMetadata(attributes, containerType, modelAccessor, modelType, propertyName); ;
}
}
Register it using:
ModelMetadataProviders.Current = new MyModelMetadataProvider();
Still, since the core problem is a client-side problem, I would deal with it purely with client-side code. In your monthyeardate adapter you can force removal of the date validation (I can provide an example if you'll share your monthyeardate code).
See MSDN
This is hacky but one simple thing you could do is add:
$(function () {
$.validator.methods.date = function () { return true; };
});
So that the default data-val-date always returns true along with firing your custom date validation.
I know that this is a little older, and just in case someone doesn't think about it (and since I cannot leave comments yet), to enhance #AlexC response, you can add validation to to that statement.
For instance, I use moment.js for date validation (moment.js), and this allows you to add your own validation rules.
if (moment(a, "M/YYYY").isValid() || moment(a).isValid())
{
return true;
}
This will check to see if it is a regular date, and also in this case, if the date is in "M/YYYY" format. If one of these are true, it accepts the validation.
I have the following code block: -
using System.ComponentModel.DataAnnotations;
public class NewsItem
{
[RegularExpression(System.Configuration.ConfigurationSettings.AppSettings["UrlRegEx"], ErrorMessage = "Invalid link")]
public string Url { get; set; }
}
This returns the error "An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type".
How can I give the value in the first parameter of a RegularExpression attribute. I want to give the values from Web.Config variables. I am using this code in the Model class of EF.
You can point data annotation to pick the value from resource file
See ErrorMessageResourceName
OR
You can write your custom validation method and pick the value from there
See CustomValidationAttribute
OR
You can write a regular expression derived attribute class that can reads the value from web.config.
I am very confused with properties in asp.net.
I just don't understand why we use properties and when I should use them. Could anybody elaborate a little on this.
public class Customer
{
private int m_id = -1;
public int ID
{
set
{
m_id = value;
}
}
private string m_name = string.Empty;
public string Name
{
set
{
m_name = value;
}
}
public void DisplayCustomerData()
{
Console.WriteLine("ID: {0}, Name: {1}", m_id, m_name);
}
}
Properties provide the opportunity to protect a field in a class by reading and writing to it through the property. In other languages, this is often accomplished by programs implementing specialized getter and setter methods. C# properties enable this type of protection while also letting you access the property just like it was a field.
Another benefit of properties over fields is that you can change their internal implementation over time. With a public field, the underlying data type must always be the same because calling code depends on the field being the same. However, with a property, you can change the implementation. For example, if a customer has an ID that is originally stored as an int, you might have a requirements change that made you perform a validation to ensure that calling code could never set the ID to a negative value. If it was a field, you would never be able to do this, but a property allows you to make such a change without breaking code. Now, lets see how to use properties.
Taken From CSharp-Station
There are a couple of good reasons for it. The first is that you might need to add validation logic in your setter, or actually calculate the value in the getter.
Another reason is something to do with the IL code generated. If you are working on a large project that is spread over multiple assemblies then you can change the code behind your property without the application that uses your assembly having to recompile. This is because the "access point" of the property stays the same while allowing the implementation code behind it to be altered. I first read about this when I was looking into the point of automatic properties as I didnt see the point between those and a normal public variable.
It's easy.
All fields in class MUST be private (or protected). To show fields to another class yyou can use properties or get/set methods. Properties a shorter.
P.S. Don't declare write-only properties. It is worst practices.
Properties are a convenient way to encapsulate your classes' data.
Quoting from MSDN:
A property is a member that provides a flexible mechanism to read,
write, or compute the value of a private field. Properties can be used
as if they are public data members, but they are actually special
methods called accessors. This enables data to be accessed easily and
still helps promote the safety and flexibility of methods.
Let's consider two common scenarios:
1) You want to expose the Name property without making it changeable from outside the class:
private string m_name = string.Empty;
public string Name
{
get
{
return m_name;
}
}
2) You want to perform some checks, or run some code every time the data is accessed or set:
private string m_name = string.Empty;
public string Name
{
get
{
return m_name;
}
set
{
m_name = (String.IsNullOrEmpty(value)) ? "DefaultName" : value;
}
}
see:
http://msdn.microsoft.com/en-us/library/x9fsa0sw.aspx
The most important reason is for validation purpose in setter and manipulation part can be implemented in get part.
For Ex.
Storing weekdays, which should be from 1-7, if we take normal variable and declare it as public, anyone can assign any value.
But in Properties setter you can control and validate.
The next one you can use it for tracking. That means, you can know how many times set and get functions has been called by clients (statistical purpose, may be not useful frequently).
Finally, you can control read only, write only and read/write for the properties according to your requirements.
I have a .Net Web Service function that can accept one string.
That function will then serialize that string to JSON, but I only want to serialize it if it's value is not "".
I found these instructions:
http://msdn.microsoft.com/en-us/library/aa347792.aspx
[DataContract]
public class MyClass
{
[DataMember (EmitDefaultValue=false)]
public string myValue = ""
}
Unfortunatelly I can not hide the myValue from the serialization because "" is not the .Net default value for a string (how dumb is that!)
One of two option ocurred
On the web service have some kind of attribute that sets the "" to null
Have some condition on the class
I would prefer the 1st because it makes the code cleaner but an opinion would be great.
Thanks
You can explicitly set what the default value is (for the purposes of serialization) using the DefaultValueAttribute class:
[DataContract]
public class MyClass
{
[DataMember (EmitDefaultValue=false)]
[DefaultValue("")]
public string myValue = ""
}
I think you have at least a couple of options here. It's extra work but worth it.
You can encapsulate the string in a reference type. Since reference types are null if not present, that lets you know right away if a string was present or not (because the encapsulating reference type would be either non-null or null, if the string is non-empty or not.)
A final option you have is to add an extra complementary variable (perhaps a boolean) that is set on OnDeserializing/OnDeserialized/OnSerializing/OnSerialized and use this to track whether or not something was actually present on the wire. You might, for example, set this complementary variable to true only when you're actually serializing out a non-empty string and similarly
i have a view model with a property like this one :
[RegularExpression(#"^d\+$", ErrorMessageResourceType = typeof(Resources.Validation), ErrorMessageResourceName = "NumberValidationMsg" )]
public int? Number {get; set;}
NumberValidationMsg resource is set to "Only numbers allowed !".
but when I try to enter something like 'test' into Number field on form, ModelState displays the ErrorMessage with content similar to : "The value 'test' is not valid for Number."
can this message be turned off, customized ?
(or maybe the best solution would be just to replace int? with string )
Thank You !
If you want to accept text in the field, you need to change it to a string, and make your conversions to int according to your rules.
If your model is an int, then the only valid input will be int (or empty, if it is "int?"), and you should not try to prevent this unless there are good reasons... Moreover, I believe that you could leave the whole regular expression out, because the MVC already does that check for you implicitly (because it is an int).