I have asp.net mvc3 project where I do a bulk edit on a table with knockout binding. I want to do validations like required and number validations while saving data. Is there any easier way to do knock out validations. PS: I am not using forms.
Have a look at Knockout-Validation which cleanly setups and uses what's described in the knockout documentation. Under: Live Example 1: Forcing input to be numeric
You can see it live in Fiddle
UPDATE: the fiddle has been updated to use the latest KO 2.0.3 and ko.validation 1.0.2 using the cloudfare CDN urls
To setup ko.validation:
ko.validation.rules.pattern.message = 'Invalid.';
ko.validation.configure({
registerExtenders: true,
messagesOnModified: true,
insertMessages: true,
parseInputAttributes: true,
messageTemplate: null
});
To setup validation rules, use extenders. For instance:
var viewModel = {
firstName: ko.observable().extend({ minLength: 2, maxLength: 10 }),
lastName: ko.observable().extend({ required: true }),
emailAddress: ko.observable().extend({ // custom message
required: { message: 'Please supply your email address.' }
})
};
If you don't want to use the KnockoutValidation library you can write your own. Here's an example for a Mandatory field.
Add a javascript class with all you KO extensions or extenders, and add the following:
ko.extenders.required = function (target, overrideMessage) {
//add some sub-observables to our observable
target.hasError = ko.observable();
target.validationMessage = ko.observable();
//define a function to do validation
function validate(newValue) {
target.hasError(newValue ? false : true);
target.validationMessage(newValue ? "" : overrideMessage || "This field is required");
}
//initial validation
validate(target());
//validate whenever the value changes
target.subscribe(validate);
//return the original observable
return target;
};
Then in your viewModel extend you observable by:
self.dateOfPayment: ko.observable().extend({ required: "" }),
There are a number of examples online for this style of validation.
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