I have followed some articles and tutorials over
the internet in order to create a custom validation attribute that also supports client-side validation in an asp.net mvc 4 website. This is what i have until now:
RequiredIfAttribute.cs
[AttributeUsage(AttributeTargets.Property, AllowMultiple = true)] //Added
public class RequiredIfAttribute : ValidationAttribute, IClientValidatable
{
private readonly string condition;
private string propertyName; //Added
public RequiredIfAttribute(string condition)
{
this.condition = condition;
this.propertyName = propertyName; //Added
}
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
PropertyInfo propertyInfo = validationContext.ObjectType.GetProperty(this.propertyName); //Added
Delegate conditionFunction = CreateExpression(validationContext.ObjectType, _condition);
bool conditionMet = (bool)conditionFunction.DynamicInvoke(validationContext.ObjectInstance);
if (conditionMet)
{
if (value == null)
{
return new ValidationResult(FormatErrorMessage(null));
}
}
return ValidationResult.Success;
}
private Delegate CreateExpression(Type objectType, string expression)
{
LambdaExpression lambdaExpression = System.Linq.Dynamic.DynamicExpression.ParseLambda(objectType, typeof(bool), expression); //Added
Delegate function = lambdaExpression.Compile();
return function;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
{
var modelClientValidationRule = new ModelClientValidationRule
{
ValidationType = "requiredif",
ErrorMessage = ErrorMessage //Added
};
modelClientValidationRule.ValidationParameters.Add("param", this.propertyName); //Added
return new List<ModelClientValidationRule> { modelClientValidationRule };
}
}
Then i applied this attribute in a property of a class like this
[RequiredIf("InAppPurchase == true", "InAppPurchase", ErrorMessage = "Please enter an in app purchase promotional price")] //Added "InAppPurchase"
public string InAppPurchasePromotionalPrice { get; set; }
public bool InAppPurchase { get; set; }
So what i want to do is display an error message that field InAppPurchasePromotionalPrice is required when InAppPurchase field is true (that means checked in
the form).
The following is
the relevant code form
the view:
<div class="control-group">
<label class="control-label" for="InAppPurchase">Does your app include In App Purchase?</label>
<div class="
controls">
@Html.CheckBoxFor(o => o.InAppPurchase)
@Html.LabelFor(o => o.InAppPurchase, "Yes")
</div>
</div>
<div class="control-group" id="InAppPurchasePromotionalPriceDiv" @(Model.InAppPurchase == true ? Html.Raw("style='display: block;'") : Html.Raw("style='display: none;'"))>
<label class="control-label" for="InAppPurchasePromotionalPrice">App Friday Promotional Price for In App Purchase: </label>
<div class="
controls">
@Html.TextBoxFor(o => o.InAppPurchasePromotionalPrice, new { title = "This should be at
the lowest price tier of free or $.99, just for your App Friday date." })
<span class="help-inline">
@Html.ValidationMessageFor(o => o.InAppPurchasePromotionalPrice)
</span>
</div>
</div>
This code works perfectly but when i submit
the form a full post is requested on
the server in order to display
the message. So i created JavaScript code to enable client-side validation:
requiredif.js
(function ($) {
$.validator.addMethod('requiredif', function (value, element, params) {
/*var inAppPurchase = $('#InAppPurchase').is(':checked');
if (inAppPurchase) {
return true;
}
return false;*/
var isChecked = $(param).is(':checked');
if (isChecked) {
return false;
}
return true;
}, '');
$.validator.unobtrusive.adapters.add('requiredif', ['param'], function (options) {
options.rules["requiredif"] = '#' + options.params.param;
options.messages['requiredif'] = options.message;
});
})(jQuery);
This is
the proposed way in msdn and tutorials i have found
Of course i have also inserted
the needed scripts in
the form:
jquery.unobtrusive-ajax.min.js
jquery.validate.min.js
jquery.validate.unobtrusive.min.js
requiredif.js
BUT...client side validation still does not work. So could you please help me find what am i missing? Thanks in advance.
