I've followed this tutorial to create a custom dynamic backend configuration with serialized data, and everything is working as expected. yay
But now I want to take another step and only show some inputs when a specific value is selected in a select box. I know that I can use when doing this with system.xml, but how can I accomplish the same thing via code with dynamics serialized tables?
I ended up doing some kind of Javascript workaround to enable/disable a certain input.
function togleSelect(element)
{
var val = element.value;
var name = element.name;
if (val == 0) // select value to be triggered
{
name = name.substr(0, name.lastIndexOf("[")) + "[name_of_my_input]";
var target = document.getElementsByName(name);
target[0].disabled = false;
}
else
{
name = name.substr(0, name.lastIndexOf("[")) + "[name_of_my_input]";
var target = document.getElementsByName(name);
target[0].disabled = true;
}
}
It's not the best solution but it's working.
Is there a way that when I read an object from Realm that it can become a standalone or unmanaged object? In EF, this is called no tracking. The usage for this would be when I want to implement more business logic on my data objects before they are updated on the persistent data storage. I may want to give the RealmObject to a ViewModel, but when the changes come back from the ViewModel, I want to compare the disconnected object to the object in the datastore to determine what was changed, so If there was a way that I could disconnect the object from Realm when I give it to the ViewModel, then I can better manage what properties have changed, using my biz logic to do what I need, then save the changes back to realm.
I understand Realm does a lot of magic and many people will not want to add a layer like this but in my app, I cant really have the UI directly updating the datastore, unless there is a event that is raised that I can subscribe too and then attach my business logic this way.
I only saw one event and it does not appear to perform this action.
Thanks for your assistance.
First, get json NUGET :
PM> Install-Package Newtonsoft.Json
And, try this "hack" :
Deserialize the modified IsManaged property does the tricks.
public d DetachObject<d>(d Model) where d : RealmObject
{
return Newtonsoft.Json.JsonConvert.DeserializeObject<d>(
Newtonsoft.Json.JsonConvert.SerializeObject(Model)
.Replace(",\"IsManaged\":true", ",\"IsManaged\":false")
);
}
.
If you facing slow-down on JsonConvert:
According to source code
, the 'IsManaged' property only has get accessor and return true when private field _realm which is available
So, we has to set the instance of field _realm to null does the tricks
public d DetachObject<d>(d Model) where d : RealmObject
{
typeof(RealmObject).GetField("_realm",
System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic)
.SetValue(Model, null);
return Model.IsManaged ? null : Model;
}
.
You will get empty RealmObject body after Realm are now implemented same strategy as LazyLoad
Record down live RealmObject and (deactivate) realm instance in object by Reflection. And set back recorded values to RealmObject. With handled all the ILists inside too.
public d DetachObject<d>(d Model) where d : RealmObject
{
return (d)DetachObjectInternal(Model);
}
private object DetachObjectInternal(object Model)
{
//Record down properties and fields on RealmObject
var Properties = Model.GetType().GetProperties(System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Public)
.Where(x => x.Name != "ObjectSchema" && x.Name != "Realm" && x.Name != "IsValid" && x.Name != "IsManaged" && x.Name != "IsDefault")
.Select(x =>(x.PropertyType.Name == "IList`1")? ("-" + x.Name, x.GetValue(Model)) : (x.Name, x.GetValue(Model))).ToList();
var Fields = Model.GetType().GetFields(System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Public)
.Select(x => (x.Name, x.GetValue(Model))).ToList();
//Unbind realm instance from object
typeof(RealmObject).GetField("_realm", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic).SetValue(Model, null);
//Set back the properties and fields into RealmObject
foreach (var field in Fields)
{
Model.GetType().GetField(field.Item1, System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Public).SetValue(Model, field.Item2);
}
foreach (var property in Properties.OrderByDescending(x=>x.Item1[0]).ToList())
{
if (property.Item1[0] == '-')
{
int count = (int)property.Item2.GetType().GetMethod("get_Count").Invoke(property.Item2, null);
if (count > 0)
{
if (property.Item2.GetType().GenericTypeArguments[0].BaseType.Name == "RealmObject")
{
for (int i = 0; i < count; i++)
{
var seter = property.Item2.GetType().GetMethod("set_Item");
var geter = property.Item2.GetType().GetMethod("get_Item");
property.Item2.GetType().GetField("_realm", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Public).SetValue(property.Item2, null);
DetachObjectInternal(geter.Invoke(property.Item2, new object[] { i }));
}
}
}
}
else
{
Model.GetType().GetProperty(property.Item1, System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Public).SetValue(Model, property.Item2);
}
}
return Model;
}
.
For List of the RealmObject , Using Select():
DBs.All<MyRealmObject>().ToList().Select(t => DBs.DetachObject(t)).ToList();
.
(Java)You dont need this if youre in java:
Maybe some day, this feature will come to .NET Realm
Realm.copyFromRealm();
#xamarin #C# #Realm #RealmObject #detach #managed #IsManaged #copyFromRealm
Until its added to Realm for Xamarin, I added a property to my Model that creates a copy of the object. This seems to work for my use. The TwoWay Binding error messages are now also not an issue. For a more complicated application, I don't want to put business or data logic in the ViewModel. This allows all the Magic of xamarin forms to work and me to implement logic when its finally time to save the changes back to realm.
[Ignored]
public Contact ToStandalone()
{
return new Contact()
{
companyName = this.companyName,
dateAdded = this.dateAdded,
fullName = this.fullName,
gender = this.gender,
website = this.website
};
}
However, If there are any relationships this method does not work for the relationships. Copying the List is not really an option either as the relationship cant exist if the object is not attached to Realm, I read this some where, can't find it to ref now. So I guess we will be waiting for the additions to the framework.
Not currently in the Xamarin interface but we could add it. The Java interface already has copyFromRealm which performs a deep copy. That also has a paired merging copyToRealmOrUpdate.
See Realm github issue for further discussion.
However, as a design issue, is this really meeting your need in an optimal way?
I have used converters in WPF apps to insert logic into the binding - these are available in Xamarin Forms.
Another way in Xamarin forms is to use Behaviours, as introduced in the blog article and covered in the API.
These approaches are more about adding logic between the UI and ViewModel, which you could consider as part of the ViewModel, but before updates are propagated to bound values.
After wasting too much time in 3rd party libraries like AutoMapper, I've created my own extension function which works pretty well. This function simply uses Reflection with the recession. (Currently, Only for List type. You can extend the functionality for Dictionary and other types of the collection very easily or you can completely modify the functionality based on your own requirements.).
I didn't do too much time and complexity analysis. I've tested only for my test case which contains many nested RealmObject, built from a 3500+ line of JSON object, took only 15 milliseconds to clone the object.
Here the complete extension available via Github Gist. If you want to extend the functionality of this extension please update this Github Gist, So, other developers can take advantage of it.
Here the complete extension -
using System;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;
using Realms;
namespace ProjectName.Core.Extensions
{
public static class RealmExtension
{
public static T Clone<T>(this T source) where T: new()
{
//If source is null return null
if (source == null)
return default(T);
var target = new T();
var targetType = typeof(T);
//List of skip namespaces
var skipNamespaces = new List<string>
{
typeof(Realm).Namespace
};
//Get the Namespace name of Generic Collection
var collectionNamespace = typeof(List<string>).Namespace;
//flags to get properties
var flags = BindingFlags.IgnoreCase | BindingFlags.DeclaredOnly | BindingFlags.Public | BindingFlags.Instance;
//Get target properties list which follows the flags
var targetProperties = targetType.GetProperties(flags);
//if traget properties is null then return default target
if (targetProperties == null)
return target;
//enumerate properties
foreach (var property in targetProperties)
{
//skip property if it's belongs to namespace available in skipNamespaces list
if (skipNamespaces.Contains(property.DeclaringType.Namespace))
continue;
//Get property information and check if we can write value in it
var propertyInfo = targetType.GetProperty(property.Name, flags);
if (propertyInfo == null || !property.CanWrite)
continue;
//Get value from the source
var sourceValue = property.GetValue(source);
//If property derived from the RealmObject then Clone that too
if (property.PropertyType.IsSubclassOf(typeof(RealmObject)) && (sourceValue is RealmObject))
{
var propertyType = property.PropertyType;
var convertedSourceValue = Convert.ChangeType(sourceValue, propertyType);
sourceValue = typeof(RealmExtension).GetMethod("Clone", BindingFlags.Static | BindingFlags.Public)
.MakeGenericMethod(propertyType).Invoke(convertedSourceValue, new[] { convertedSourceValue });
}
//Check if property belongs to the collection namespace and original value is not null
if (property.PropertyType.Namespace == collectionNamespace && sourceValue != null)
{
//get the type of the property (currently only supported List)
var listType = property.PropertyType;
//Create new instance of listType
var newList = (IList)Activator.CreateInstance(listType);
//Convert source value into the list type
var convertedSourceValue = Convert.ChangeType(sourceValue, listType) as IEnumerable;
//Enumerate source list and recursively call Clone method on each object
foreach (var item in convertedSourceValue)
{
var value = typeof(RealmExtension).GetMethod("Clone", BindingFlags.Static | BindingFlags.Public)
.MakeGenericMethod(item.GetType()).Invoke(item, new[] { item });
newList.Add(value);
}
//update source value
sourceValue = newList;
}
//set updated original value into the target
propertyInfo.SetValue(target, sourceValue);
}
return target;
}
}
}
I am using the OData sample project at http://www.asp.net/web-api/overview/odata-support-in-aspnet-web-api/working-with-entity-relations. In the Get I want to be able to change the Filter in the QueryOptions of the EntitySetController:
public class ProductsController : EntitySetController<Product, int>
{
ProductsContext _context = new ProductsContext();
[Queryable(AllowedQueryOptions=AllowedQueryOptions.All)]
public override IQueryable<Product> Get()
{
var products = QueryOptions.ApplyTo(_context.Products).Cast<Product>();
return products.AsQueryable();
}
I would like to be able to find properties that are specifically referred to. I can do this by parsing this.QueryOptions.Filter.RawValue for the property names but I cannot update the RawValue as it is read only. I can however create another instance of FilterQueryOption from the modified RawValue but I cannot assign it to this.QueryOptions.Filter as this is read only too.
I guess I could call the new filter's ApplyTo passing it _context.Products, but then I will need to separately call the ApplyTo of the other properties of QueryOptions like Skip and OrderBy. Is there a better solution than this?
Update
I tried the following:
public override IQueryable<Product> Get()
{
IQueryable<Product> encryptedProducts = _context.Products;
var filter = QueryOptions.Filter;
if (filter != null && filter.RawValue.Contains("Name"))
{
var settings = new ODataQuerySettings();
var originalFilter = filter.RawValue;
var newFilter = ParseAndEncyptValue(originalFilter);
filter = new FilterQueryOption(newFilter, QueryOptions.Context);
encryptedProducts = filter.ApplyTo(encryptedProducts, settings).Cast<Product>();
if (QueryOptions.OrderBy != null)
{
QueryOptions.OrderBy.ApplyTo<Product>(encryptedProducts);
}
}
else
{
encryptedProducts = QueryOptions.ApplyTo(encryptedProducts).Cast<Product>();
}
var unencryptedProducts = encryptedProducts.Decrypt().ToList();
return unencryptedProducts.AsQueryable();
}
and it seems to be working up to a point. If I set a breakpoint I can see my products in the unencryptedProducts list, but when the method returns I don't get any items. I tried putting the [Queryable(AllowedQueryOptions=AllowedQueryOptions.All)] back on again but it had no effect. Any ideas why I am not getting an items?
Update 2
I discovered that my query was being applied twice even though I am not using the Queryable attribute. This meant that even though I had items to return the List was being queried with the unencrypted value and therefore no values were being returned.
I tried using an ODataController instead:
public class ODriversController : ODataController
{
//[Authorize()]
//[Queryable(AllowedQueryOptions = AllowedQueryOptions.All)]
public IQueryable<Products> Get(ODataQueryOptions options)
{
and this worked! Does this indicate that there is a bug in EntitySetController?
You would probably need to regenerate ODataQueryOptions to solve your issue. Let's say if you want to modify to add $orderby, you can do this like:
string url = HttpContext.Current.Request.Url.AbsoluteUri;
url += "&$orderby=name";
var request = new HttpRequestMessage(HttpMethod.Get, url);
ODataModelBuilder modelBuilder = new ODataConventionModelBuilder();
modelBuilder.EntitySet<Product>("Product");
var options = new ODataQueryOptions<Product>(new ODataQueryContext(modelBuilder.GetEdmModel(), typeof(Product)), request);
I'm working on an ASP.Net MVC application. My action is returning a view with a model that is an array of objects (a class with properties like Name, ID, IsViewable).
var model = #Model.ToJson(); // done via extension call
I want to observe this array, so whenever it changes I can update a table that has been bound to a template.
var viewModel = {
accounts = ko.observableArray(model)
}
This works just fine for adding and deleting elements from the array. However, I also want the template to update when a property in one of the accounts changes (ie, Name or ID).
On the KnockoutJS website, it says: Of course, you can make those properties observable if you wish, but that’s an independent choice. This is what I cannot figure out how to do.
I tried something like this with no avail:
var viewModel = {
accounts = ko.oservableArray([])
}
for(var i = 0; i < model.length; i++) {
ko.observableArray(model[i]);
viewModel.accounts.push(model[i]);
}
I can post the template and the table if it's needed.
You should look into the knockout.mapping plugin. I think it does everything you are looking to do.
I ended up getting this to work, so I thought I would share with anyone that might have having the same problem.
You need to wrap your array items in a JavaScript class. Then in the constructor, set each property to obserable:
var model = #Model.ToJson();
var viewModel = {
accounts = ko.observableArray(ko.utils.arrayMap(model, function(account) {
return new AccountWrapper(account);
}))
};
function AccountWrapper(account) {
this.Property1 = ko.observable(account.Propery1);
this.Property2 = ko.observable(account.Propery2);
this.Property3 = ko.observable(account.Propery3);
}
ko.applyBindings(viewModel);
And if you want to modify one of the items directly to see the change, you could do something like:
viewModel.accounts()[3].Name('My Name Changed');
And you can still get notified when items are added or remove:
viewModel.accounts.remove(viewModel.accounts()[4]);
Here's another approach that works and doesn't require the mapping plugin:
var model = #Model.ToJson();
var viewModel = {
accounts: ko.observableArray([]),
fromJS: function(js) {
for (var i = 0; i < js.length; i++) {
this.accounts.push({
Property1: ko.observable(js[i].Property1),
Property2: ko.observable(js[i].Property2),
Property3: ko.observable(js[i].Property3)
});
}
}
};
viewModel.fromJS(model);
ko.applyBindings(viewModel);
I want to get a collection of all label controls that are part of a user control. I have the following code:
var labelControls = from Control ctl in this.Controls
where ctl.GetType() == typeof(Label)
select ctl;
but the result is zero results.
Please assist. Thanks.
Edit
I have also tried the following code without success.
this.Controls
.OfType<Label>()
.Where(ctl => ctl.ID.Contains("myPrefix"))
.ToList()
.ForEach(lbl => lbl.ForeColor = System.Drawing.Color.Black);
Again, without success.
Are you sure that the control whose child controls you are parsing actually directly contains Label controls? I suspect that it is a child of the main control that is hosting the labels, in which case, you need to recursively search through the UI tree to find the labels.
Something like:
public static IEnumerable<Label> DescendantLabels(this Control control)
{
return control.Controls.DescendantLabels();
}
public static IEnumerable<Label> DescendantLabels(this ControlCollection controls)
{
var childControls = controls.OfType<Label>();
foreach (Control control in controls)
{
childControls = childControls.Concat(control.DescendantLabels());
}
return childControls;
}
Controls.OfType<Label>() - thats all
For nested controls
public static class ext
{
public static List<Label> GetLabels(this Control control)
{
var chList = control.Controls.OfType<Label>().ToList();
chList.AddRange(((IEnumerable<Control>)control.Controls)
.SelectMany(c => c.GetLabels()));
return chList;
}
}
var labelControls = this.Controls.OfType<Label>();