Client-side validation for custom ValidationAttribute with AttributeTargets.Class
Is it possible to implement client-site validation for custom ValidationAttribute, which is used in Class scope? For example my MaxLengthGlobal, which should assure global max limit for all input fields.
[AttributeUsage(AttributeTargets.Class)]
public class MaxLengthGlobalAttribute : ValidationAttribute, IClientValidatable
{
public int MaximumLength
{
get;
private set;
}
public MaxLengthGlobalAttribute(int maximumLength)
{
this.MaximumLength = maximumLength;
}
public override bool IsValid(object value)
{
var properties = TypeDescriptor.GetProperties(value);
foreach (PropertyDescriptor property in properties)
{
var stringValue = property.GetValue(value) as string;
if (stringValue != null && (stringValue.Length > this.MaximumLength))
{
return false;
}
}
return true;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
{
va开发者_开发问答r rule = new ModelClientValidationRule
{
ErrorMessage = this.FormatErrorMessage(metadata.GetDisplayName()),
ValidationType = "maxlengthglobal",
};
rule.ValidationParameters.Add("maxlength", this.MaximumLength);
yield return rule;
}
}
Thank you.
I found this answer while looking for a solution to the same problem, and came up with a workaround.
Instead of 1 ValidationAttribute, have 2:
1.) A ServerValidationAttribute will be on the class, and will not implement IClientValidatable.
[AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = true)]
public class MyCustomServerValidationAttribute : ValidationAttribute
{
public override bool IsValid(object value)
{
// remember to cast to the class type, not property type
// ... return true or false
}
}
2.) A ClientValidationAttribute will be on the field / property, and will implement IClientValidatable, but the IsValid override always returns true.
[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property,
AllowMultiple = false, Inherited = true)]
public class MyCustomClientValidationAttribute : ValidationAttribute,
IClientValidatable
{
public override bool IsValid(object value)
{
return true;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(
ModelMetadata metadata, ControllerContext context)
{
var rule = new ModelClientValidationRule
{
ErrorMessage = ErrorMessage,
ValidationType = "mycustomvalidator",
};
var viewContext = (ViewContext)context;
var dependentProperty1 = viewContext.ViewData.TemplateInfo
.GetFullHtmlFieldId("DependentProperty1");
//var prefix = viewContext.ViewData.TemplateInfo.HtmlFieldPrefix;
rule.ValidationParameters.Add("dependentproperty1", dependentProperty1);
yield return rule;
}
}
When executed on the client, the server attribute is ignored, and vice versa.
If you need to have a validation attribute on the class, chances are the validation happens against multiple fields. I dropped in some boilerplate code for passing additional parameters to the client validation method, but it's not working as I expected. In my actual code I have commented out the viewContext and dependentProperty1 vars, and just passed a "DependentProperty1" string to the second argument of the rule.ValidationParameters.Add method. For some reason, I'm getting an incorrect HtmlFieldPrefix. If anyone can help with this please comment...
Anyway, you end up with a viewmodel like this:
[MyCustomServerValidation(ErrorMessage = MyCustomValidationMessage)]
public class MyCustomViewModel
{
private const string MyCustomValidationMessage = "user error!";
[Display(Name = "Email Address")]
[MyCustomClientValidation(ErrorMessage = MyCustomValidationMessage)]
public string Value { get; set; }
[HiddenInput(DisplayValue = false)]
public string DependentProperty1 { get; set; }
}
A client script like this:
/// <reference path="jquery-1.6.2.js" />
/// <reference path="jquery.validate.js" />
/// <reference path="jquery.validate.unobtrusive.js" />
$.validator.addMethod('mycustomvalidator', function (value, element, parameters) {
var dependentProperty1 = $('#' + parameters['dependentproperty1']).val();
// return true or false
});
$.validator.unobtrusive.adapters.add('mycustomvalidator', ['dependentproperty1'],
function (options) {
options.rules['mycustomvalidator'] = {
dependentproperty1: options.params['dependentproperty1']
};
options.messages['mycustomvalidator'] = options.message;
}
);
And a view like this:
@Html.EditorFor(m => m.Value)
@Html.EditorFor(m => m.DependentProperty1)
@Html.ValidationMessageFor(m => m.Value)
@Html.ValidationMessageFor(m => m)
Then if you have client validation disabled, the @Html.ValidationMessageFor(m => m)
is displayed instead of the one for the property.
Nope, it's not possible. Sorry.
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