Clear Up
SharpKit Reference

Field Class

Namespace: Ext.data

Base Types

System.Object

Constructors

Properties

Name Description
alias @extends Object @author Ed Spencer * Fields are used to define what a Model is. They aren't instantiated directly - instead, when we create a class that extends {@link Ext.data.Model}, it will automatically create a Field instance for each field configured in a {@link Ext.data.Model Model}. For example, we might set up a model like this: * Ext.define('User', { extend: 'Ext.data.Model', fields: [ 'name', 'email', {name: 'age', type: 'int'}, {name: 'gender', type: 'string', defaultValue: 'Unknown'} ] }); * Four fields will have been created for the User Model - name, email, age and gender. Note that we specified a couple of different formats here; if we only pass in the string name of the field (as with name and email), the field is set up with the 'auto' type. It's as if we'd done this instead: * Ext.define('User', { extend: 'Ext.data.Model', fields: [ {name: 'name', type: 'auto'}, {name: 'email', type: 'auto'}, {name: 'age', type: 'int'}, {name: 'gender', type: 'string', defaultValue: 'Unknown'} ] }); * # Types and conversion * The {@link #type} is important - it's used to automatically convert data passed to the field into the correct format. In our example above, the name and email fields used the 'auto' type and will just accept anything that is passed into them. The 'age' field had an 'int' type however, so if we passed 25.4 this would be rounded to 25. * Sometimes a simple type isn't enough, or we want to perform some processing when we load a Field's data. We can do this using a {@link #convert} function. Here, we're going to create a new field based on another: * Ext.define('User', { extend: 'Ext.data.Model', fields: [ 'name', 'email', {name: 'age', type: 'int'}, {name: 'gender', type: 'string', defaultValue: 'Unknown'}, * { name: 'firstName', convert: function(value, record) { var fullName = record.get('name'), splits = fullName.split(" "), firstName = splits[0]; * return firstName; } } ] }); * Now when we create a new User, the firstName is populated automatically based on the name: * var ed = Ext.create('User', {name: 'Ed Spencer'}); * console.log(ed.get('firstName')); //logs 'Ed', based on our convert function * In fact, if we log out all of the data inside ed, we'll see this: * console.log(ed.data); * //outputs this: { age: 0, email: "", firstName: "Ed", gender: "Unknown", name: "Ed Spencer" } * The age field has been given a default of zero because we made it an int type. As an auto field, email has defaulted to an empty string. When we registered the User model we set gender's {@link #defaultValue} to 'Unknown' so we see that now. Let's correct that and satisfy ourselves that the types work as we expect: * ed.set('gender', 'Male'); ed.get('gender'); //returns 'Male' * ed.set('age', 25.4); ed.get('age'); //returns 25 - we wanted an int, not a float, so no decimal places allowed
allowBlank @cfg {Boolean} allowBlank @private * Used for validating a {@link Ext.data.Model model}. Defaults to true. An empty value here will cause {@link Ext.data.Model}.{@link Ext.data.Model#isValid isValid} to evaluate to false.
dateFormat @cfg {String} dateFormat * Used when converting received data into a Date when the {@link #type} is specified as `"date"`. * A format string for the {@link Ext.Date#parse Ext.Date.parse} function, or "timestamp" if the value provided by the Reader is a UNIX timestamp, or "time" if the value provided by the Reader is a javascript millisecond timestamp. See {@link Ext.Date}.
defaultValue @cfg {Object} defaultValue * The default value used **when a Model is being created by a {@link Ext.data.reader.Reader Reader}** when the item referenced by the `{@link Ext.data.Field#mapping mapping}` does not exist in the data object (i.e. undefined). Defaults to "".
mapping @cfg {String/Number} mapping * (Optional) A path expression for use by the {@link Ext.data.reader.Reader} implementation that is creating the {@link Ext.data.Model Model} to extract the Field value from the data object. If the path expression is the same as the field name, the mapping may be omitted. * The form of the mapping expression depends on the Reader being used. * - {@link Ext.data.reader.Json} * The mapping is a string containing the javascript expression to reference the data from an element of the data item's {@link Ext.data.reader.Json#root root} Array. Defaults to the field name. * - {@link Ext.data.reader.Xml} * The mapping is an {@link Ext.DomQuery} path to the data item relative to the DOM element that represents the {@link Ext.data.reader.Xml#record record}. Defaults to the field name. * - {@link Ext.data.reader.Array} * The mapping is a number indicating the Array index of the field's value. Defaults to the field specification's Array position. * If a more complex value extraction strategy is required, then configure the Field with a {@link #convert} function. This is passed the whole row object, and may interrogate it in whatever way is necessary in order to return the desired data.
persist @cfg {Boolean} persist * False to exclude this field from the {@link Ext.data.Model#modified} fields in a model. This will also exclude the field from being written using a {@link Ext.data.writer.Writer}. This option is useful when model fields are used to keep state on the client but do not need to be persisted to the server. Defaults to true.
sortDir @cfg {String} sortDir * Initial direction to sort (`"ASC"` or `"DESC"`). Defaults to `"ASC"`.
sortType @cfg {Function} sortType * A function which converts a Field's value to a comparable value in order to ensure correct sort ordering. Predefined functions are provided in {@link Ext.data.SortTypes}. A custom sort example: * // current sort after sort we want // +-+------+ +-+------+ // |1|First | |1|First | // |2|Last | |3|Second| // |3|Second| |2|Last | // +-+------+ +-+------+ * sortType: function(value) { switch (value.toLowerCase()) // native toLowerCase(): { case 'first': return 1; case 'second': return 2; default: return 3; } }
useNull @cfg {Boolean} useNull * Use when converting received data into a Number type (either int or float). If the value cannot be parsed, null will be used if useNull is true, otherwise the value will be 0. Defaults to false.
© Copyright 2005-2011 SharpKit. All rights reserved.