Added DataForm Complex Types KB

knowledge-base/dataform-complextype-in-editors.md

@@ -0,0 +1,172 @@
+---
+title: How to use complex types in DataForm editors
+description: How to set PickerEditor to a property of custom type
+type: how-to
+page_title: Is it possible to edit a property of not primitive type in RadDataForm
+slug: dataform-complextype-in-editors 
+tags: dataform, complex, type, editor, picker editor
+ticketid: 1113888
+res_type: kb
+---
+
+## Environment
+<table>
+	<tr>
+		<td>Product Version</td>
+		<td>2018.3.1122</td>
+	</tr>
+	<tr>
+		<td>Product</td>
+		<td>DataForm for Xamarin</td>
+	</tr>
+</table>
+
+
+## Description
+In general, RadDataForm works with simple property types (string, int, long) and when you are using a custom type - the **native Data Form** is not sure what native type corresponds to the one you are using so it disregards the property. With this in mind, we have introduced a mechanism that maps the property declared in Xamarin.Forms to a native one. Below are the needed steps to enable this on Android and iOS.
+
+## Solution
+
+First, create the custom property you will use inside the DataForm PickerEditor:
+
+	public class City
+	{
+		public City(string name)
+		{
+			this.Name = name;
+		}
+		public string Name { get; set; }
+		public override bool Equals(object obj)
+		{
+			return this.Name.Equals((obj as City)?.Name);
+		}
+	}
+	
+Create a sample *SourceItem* class which will be the Source of RadDataForm, it has a property of type *City*:
+
+	public class SourceItem
+	{
+		[DisplayOptions(Header = "Name")]
+		public string Name { get; set; }
+
+		[DisplayOptions(Header = "City")]
+		public City City { get; set; }
+	}
+
+Add a simple RadDataForm definition to your page:
+
+	<telerikInput:RadDataForm x:Name="dataForm" />
+	
+Add some code for setting its Source and registering the PickerEditor in code-behind. In addition, you would need to supply a PropertyDataSourceProvider for the Picker ItemsSource:
+
+	this.dataForm.Source = new SourceItem();
+	this.dataForm.RegisterEditor(nameof(SourceItem.City), EditorType.PickerEditor);
+	this.dataForm.PropertyDataSourceProvider = new CityDataSourceProvider();
+	
+Here is the provider:
+
+	public class CityDataSourceProvider : PropertyDataSourceProvider
+	{
+		public override IList GetSourceForKey(object key)
+		{
+			if (key.ToString().Equals("City"))
+			{
+				return new ObservableCollection<City>
+				{
+					new City("Tokyo"),
+					new City("London"),
+					new City("Paris"),
+					new City("New York City"),
+					new City("Brussels"),
+					new City("Berlin"),
+					new City("Sofia")
+				};
+				}
+			return null;
+		}
+	}
+	
+That's all on the shared project.
+
+Now, let's continue the implementation with the Android project. The *City* type should be converted to a Java type through a Telerik.XamarinForms.Common.Android.TypeRegister inside the MainActivity.cs file of the Android project (call it before LoadApplication):
+
+	public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
+	{
+		protected override void OnCreate(Bundle savedInstanceState)
+		{
+			...
+			TypeRegister.Register(typeof(City), typeof(JavaCity), new MyTypeConverter());
+			LoadApplication(new App());
+		}
+		...
+	}
+
+Add the needed MyTypeConverter and JavaCity classes:
+
+	public class JavaCity : ConvertibleObject<City>
+	{
+		public JavaCity(City instance) : base(instance)
+		{
+		}
+		// the display value in editor
+		public override string ToString()
+		{
+			return Instance.Name;
+		}
+	}
+
+	public class MyTypeConverter : ITypeConverter
+	{
+		public Java.Lang.Object Convert(object sourceObject)
+		{
+			return new JavaCity((City)sourceObject);
+		}
+		public object ConvertBack(Java.Lang.Object nativeObject)
+		{
+			return (nativeObject as JavaCity).Instance;
+		}
+	}
+	
+Lastly, let's go to the iOS project. Again, go to AppDelegate.cs and add the needed code to convert the City type through Telerik.XamarinForms.Common.iOS.TypeRegister method:
+
+	public override bool FinishedLaunching(UIApplication app, NSDictionary options)
+	{
+		global::Xamarin.Forms.Forms.Init();
+		LoadApplication(new App());
+
+		TypeRegister.Register(typeof(City), typeof(NSCity), new MyTypeConverter());
+		return base.FinishedLaunching(app, options);
+	}
+	
+And here are the final bits:
+
+	public class NSCity : ConvertibleObject<City>
+	{
+		public NSCity(City instance) : base(instance)
+		{
+		}
+		// the display value in editor
+		public override string Description
+		{
+			get
+			{
+				return Instance.Name;
+			}
+		}
+	}
+	public class MyTypeConverter : ITypeConverter
+	{
+		public NSObject Convert(object sourceObject)
+		{
+			return new NSCity((City)sourceObject);
+		}
+
+		public object ConvertBack(NSObject nativeObject)
+		{
+			return (nativeObject as NSCity).Instance;
+		}
+	}
+	
+Here is the DataForm while setting City property:
+
+![](images/dataform-complextype-editor.png)