ModelItem Class
Represents a single item in the editing model. An item can be anything from a complex data structure down to a color or integer.
System.Activities.Presentation.Model::ModelItem
System.Activities.Presentation.Model::ModelItemCollection
System.Activities.Presentation.Model::ModelItemDictionary
Assembly: System.Activities.Presentation (in System.Activities.Presentation.dll)
The ModelItem type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | Attributes | Returns the attributes declared on this item. |
![]() | Content | Returns the ContentPropertyAttribute of the item, or nullptr. |
![]() | ItemType | Returns the type of object that the item represents. |
![]() | Name | Represents the name or ID of the item. |
![]() | Parent | Returns the item that is the parent of this item. |
![]() | Parents | Returns all parents of this item. |
![]() | Properties | Returns the public properties on this item. |
![]() | Root | Returns the item that is the root of this tree. |
![]() | Source | Returns the property that provided this value. |
![]() | Sources | Returns all the properties that hold this value. |
![]() | View | Returns a DependencyObject that graphically represents this item. |
| Name | Description | |
|---|---|---|
![]() | BeginEdit() | Opens an editing scope for the designer. After an editing scope is open, all changes across all objects will be saved into the scope until the transaction is completed or reverted. Editing scopes can be nested, but must be committed in order. |
![]() | BeginEdit(String) | Opens an editing scope for the designer. After an editing scope is open, all changes across all objects will be saved into the scope until the transaction is completed or reverted. Editing scopes can be nested, but must be committed in order. |
![]() | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetCurrentValue | Returns the current value of the underlying model object that the ModelItem is wrapping. |
![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | ToString | Returns a string representation of the underlying model object contained in this model item. (Overrides Object::ToString().) |
| Name | Description | |
|---|---|---|
![]() | PropertyChanged | Implements INotifyPropertyChanged. Use this event to listen for changes to the model. This is also used by the data binding features of WPF. |
| Name | Description | |
|---|---|---|
![]() | Focus() | Overloaded. Sets the keyboard focus on the specified designer item. (Defined by ModelItemExtensions.) |
![]() | Focus(Int32) | Overloaded. Sets the keyboard focus on the specified designer item. (Defined by ModelItemExtensions.) |
![]() | GetEditingContext | Retrieves the editing context of the specified model item. (Defined by ModelItemExtensions.) |
![]() | GetModelPath | Retrieves the path of the specified model item. (Defined by ModelItemExtensions.) |
![]() | IsParentOf | Returns a value that indicates whether the first specified designer item is a parent of the second specified designer item. (Defined by ModelItemExtensions.) |
You can access the item’s properties through its Properties collection and make changes to the values of the properties.
A ModelItem is a wrapper around the underlying data model of the designer. You can access the underlying model through the GetCurrentValue() method.
Note |
|---|
Any changes you make to an object returned from the GetCurrentValue() method will not be reflected by the serialization and undo systems of the designer. |
The ModelItem can be thought of as a thin proxy for an object at which it points. First define a simple Animal object.
public class Animal
{
// simple property
public string Name { get; set; }
// complex property
public Location Residence { get; set; }
// list
public List<Animal> CloseRelatives { get; set; }
// dictionary
public Dictionary<string, object> Features { get; set; }
}
public class Location
{
public string StreetAddress { get; set; }
public string City { get; set; }
public string State { get; set; }
}
Secondly, create an instance of that Animal and a ModelItem that is a proxy for it. The object can then be retrieved by calling GetCurrentValue(). The following code also shows how to use other properties defined by ModelItem.
EditingContext ec = new EditingContext();
var companion1 = new Animal { Name = "Houdini the parakeet" };
var companion2 = new Animal { Name = "Groucho the fish" };
var animal = new Animal
{
Name = "Sasha the pug",
Residence = new Location
{
StreetAddress = "123 Main Street",
City = "AnyTown",
State = "Washington"
},
Features = {
{"noise", "snort" },
{"MeanTimeUntilNaps", TimeSpan.FromMinutes(15) }
},
CloseRelatives = { companion1, companion2 }
};
ModelTreeManager mtm = new ModelTreeManager(ec); mtm.Load(animal);
ModelItem mi = mtm.Root;
//Testing other properties of the class
ModelItem root = mtm.Root;
Assert.IsTrue(root.GetCurrentValue() == animal, "GetCurrentValue() returns same object");
Assert.IsTrue(root.ItemType == typeof(Animal),"ItemType describes the item");
Assert.IsTrue(root.Parent == null,"root parent is null");
Assert.IsTrue(root.Source == null, "root source is null");
Assert.IsTrue(((List<Animal>)root.Properties["CloseRelatives"].ComputedValue)[0] == companion1,
"ComputedValue of prop == actual object");
Assert.IsFalse(((List<Animal>)root.Properties["CloseRelatives"].ComputedValue)[0] == companion2,
"ComputedValue of prop == actual object");
Assert.AreEqual(root.Properties["Residence"].
Value.
Properties["StreetAddress"].
Value.GetCurrentValue(), "123 Main Street", "get actual value back out");
Assert.AreEqual(root, root.Properties["Residence"].Parent, "property points to owner");
ModelItem location = root.Properties["Residence"].Value;
Assert.AreEqual(root.Properties["Residence"], location.Source, "sources point to the right place");
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
