Specifies that the designer for a class belongs to a certain category.
Assembly: System (in System.dll)
Thetype exposes the following members.
|Equals||Infrastructure. Returns whether the value of the given object is equal to the current DesignOnlyAttribute. (Overrides Attribute.Equals(Object).)|
|GetHashCode||Infrastructure. Returns the hash code for this instance. (Overrides Attribute.GetHashCode.)|
|GetType||Gets the Type of the current instance. (Inherited from Object.)|
|IsDefaultAttribute||Infrastructure. Determines if this attribute is the default. (Overrides Attribute.IsDefaultAttribute.)|
|Match||When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)|
|ToString||Returns a string that represents the current object. (Inherited from Object.)|
|Component||Specifies that a component marked with this category use a component designer. This field is read-only.|
|Default||Infrastructure. Specifies that a component marked with this category cannot use a visual designer. This static field is read-only.|
|Form||Specifies that a component marked with this category use a form designer. This static field is read-only.|
|Generic||Specifies that a component marked with this category use a generic designer. This static field is read-only.|
|_Attribute.GetIDsOfNames||Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)|
|_Attribute.GetTypeInfo||Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)|
|_Attribute.GetTypeInfoCount||Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)|
|_Attribute.Invoke||Provides access to properties and methods exposed by an object. (Inherited from Attribute.)|
A visual designer can use a designer category to inform a development environment of the type of designer that will be implemented. If no designer category is provided on a class, a development environment may or may not allow the class to be designed. A category can be created for any name.
When you mark a class with this attribute, it is set to a constant member. When you want to check the value of this attribute in your code, you must specify the constant member. The Description column in the table below lists the constant member that each value is set to.
The class defines the following common categories:
Designers that are used with components. The attribute is set to the constant member DesignerCategoryAttribute.Component.
Designers that are used with forms. The attribute is set to the constant member DesignerCategoryAttribute.Form.
Designers that are used with designers. The attribute is set to the constant member DesignerCategoryAttribute.Generic.
Empty String ("")
This is the default category.
For more information, see Extending Metadata Using Attributes.
The next example creates an instance of MyForm. Then it gets the attributes for the class, extracts the , and prints the name of the designer.
Public Shared Function Main() As Integer ' Creates a new form. Dim myNewForm As New MyForm() ' Gets the attributes for the collection. Dim attributes As AttributeCollection = TypeDescriptor.GetAttributes(myNewForm) ' Prints the name of the designer by retrieving the ' DesignerCategoryAttribute from the AttributeCollection. Dim myAttribute As DesignerCategoryAttribute = _ CType(attributes(GetType(DesignerCategoryAttribute)), DesignerCategoryAttribute) Console.WriteLine(("The category of the designer for this class is: " + myAttribute.Category)) Return 0 End Function 'Main
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.