ViewDataDictionary Class

Represents a container that is used to pass data between a controller and a view.

Inheritance Hierarchy

System.Object
  System.Web.Mvc.ViewDataDictionary
    System.Web.Mvc.ViewDataDictionary<TModel>

Namespace:  System.Web.Mvc
Assembly:  System.Web.Mvc (in System.Web.Mvc.dll)

Syntax

'Declaration
Public Class ViewDataDictionary _
    Implements IDictionary(Of String, Object),  _
    ICollection(Of KeyValuePair(Of String, Object)), IEnumerable(Of KeyValuePair(Of String, Object)),  _
    IEnumerable

public class ViewDataDictionary : IDictionary<string, Object>, 
    ICollection<KeyValuePair<string, Object>>, IEnumerable<KeyValuePair<string, Object>>, 
    IEnumerable

public ref class ViewDataDictionary : IDictionary<String^, Object^>, 
    ICollection<KeyValuePair<String^, Object^>>, IEnumerable<KeyValuePair<String^, Object^>>, 
    IEnumerable

The ViewDataDictionary type exposes the following members.

Constructors

	Name	Description
	ViewDataDictionary()	Initializes a new instance of the ViewDataDictionary class.
	ViewDataDictionary(Object)	Initializes a new instance of the ViewDataDictionary class by using the specified model.
	ViewDataDictionary(ViewDataDictionary)	Initializes a new instance of the ViewDataDictionary class by using the specified dictionary.

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Properties

	Name	Description
	Count	Gets the number of elements in the collection.
	IsReadOnly	Gets a value that indicates whether the collection is read-only.
	Item	Gets or sets the item that is associated with the specified key.
	Keys	Gets a collection that contains the keys of this dictionary.
	Model	Gets or sets the model that is associated with the view data.
	ModelMetadata	Gets or sets information about the model.
	ModelState	Gets the state of the model.
	TemplateInfo	Gets or sets an object that encapsulates information about the current template context.
	Values	Gets a collection that contains the values in this dictionary.

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Methods

	Name	Description
	Add(KeyValuePair<String, Object>)	Adds the specified item to the collection.
	Add(String, Object)	Adds an element to the collection using the specified key and value .
	Clear	Removes all items from the collection.
	Contains	Determines whether the collection contains the specified item.
	ContainsKey	Determines whether the collection contains an element that has the specified key.
	CopyTo	Copies the elements of the collection to an array, starting at a particular index.
	Equals	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Eval(String)	Evaluates the specified expression.
	Eval(String, String)	Evaluates the specified expression by using the specified format.
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetEnumerator	Returns an enumerator that can be used to iterate through the collection.
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	GetViewDataInfo	Returns information about the view data as defined by the expression parameter.
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	Remove(KeyValuePair<String, Object>)	Removes the first occurrence of a specified object from the collection.
	Remove(String)	Removes the element from the collection using the specified key.
	SetModel	Sets the data model to use for the view.
	ToString	Returns a string that represents the current object. (Inherited from Object.)
	TryGetValue	Attempts to retrieve the value that is associated with the specified key.

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Explicit Interface Implementations

	Name	Description
	IEnumerable.GetEnumerator	Returns an enumerator that can be used to iterate through the collection.

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Remarks

The ViewData property of a controller exposes an instance of the ViewDataDictionary class. To pass data to a view, you first add it to the controller's ViewData property in the action method that renders the view, as shown in the following example:

ViewData["color"] = "Red";

ViewData("color") = "Red"

When the view is rendered, the view data is copied to the ViewData property of the view. In the view markup, you can then access the data as shown in the following example:

<%= ViewData["color"] %>

<%= ViewData("color") %>

Similarly, you can pass data to the controller by adding the data to the ViewData property of the view, as shown in the following example:

<% ViewData["firstName"] = firstName %>

<% ViewData("firstName") = firstName %>

When the view is posted, its view data is sent to the controller, and you can then access the data in your action method as in the following example:

String firstName = ViewData["firstName"];

Dim firstName As String = ViewData("firstName")

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

See Also

Reference

System.Web.Mvc Namespace

Other Resources

Views and UI Rendering in ASP.NET MVC Applications

Passing Data in an ASP.NET MVC Application