DesignerCategoryAttribute Class

Definition

Namespace:

System.ComponentModel

Assembly:

System.ComponentModel.Primitives.dll

Source:

DesignerCategoryAttribute.cs

Specifies that the designer for a class belongs to a certain category.

public ref class DesignerCategoryAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Class, AllowMultiple=false, Inherited=true)]
public sealed class DesignerCategoryAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Class, AllowMultiple=false, Inherited=true)>]
type DesignerCategoryAttribute = class
    inherit Attribute

Public NotInheritable Class DesignerCategoryAttribute
Inherits Attribute

Inheritance

Object

Attribute

DesignerCategoryAttribute

Attributes

AttributeUsageAttribute

Examples

The following example creates a class called MyForm. MyForm has two attributes, a DesignerAttribute that specifies this class uses the DocumentDesigner, and a DesignerCategoryAttribute that specifies the Form category.

[Designer("System.Windows.Forms.Design.DocumentDesigner, System.Windows.Forms.Design",
IRootDesigner::typeid),
DesignerCategory("Form")]
ref class MyForm: public ContainerControl{
   // Insert code here.
};

[Designer("System.Windows.Forms.Design.DocumentDesigner, System.Windows.Forms.Design", 
    typeof(IRootDesigner)),
    DesignerCategory("Form")]
    
 public class MyForm : ContainerControl {
    // Insert code here.
 }

<Designer("System.Windows.Forms.Design.DocumentDesigner, System.Windows.Forms.Design", _
    GetType(IRootDesigner)), DesignerCategory("Form")> _
Public Class MyForm
    
    Inherits ContainerControl
    ' Insert code here.
End Class

The next example creates an instance of MyForm. Then it gets the attributes for the class, extracts the DesignerCategoryAttribute, and prints the name of the designer.

int main()
{
   // Creates a new form.
   MyForm^ myNewForm = gcnew MyForm;

   // Gets the attributes for the collection.
   AttributeCollection^ attributes = TypeDescriptor::GetAttributes( myNewForm );

   /* Prints the name of the designer by retrieving the 
       * DesignerCategoryAttribute from the AttributeCollection. */
   DesignerCategoryAttribute^ myAttribute = dynamic_cast<DesignerCategoryAttribute^>(attributes[ DesignerCategoryAttribute::typeid ]);
   Console::WriteLine( "The category of the designer for this class is: {0}", myAttribute->Category );
   return 0;
}

public static int Main() {
    // Creates a new form.
    MyForm myNewForm = new MyForm();
 
    // Gets the attributes for the collection.
    AttributeCollection attributes = TypeDescriptor.GetAttributes(myNewForm);
 
    /* Prints the name of the designer by retrieving the 
     * DesignerCategoryAttribute from the AttributeCollection. */
    DesignerCategoryAttribute myAttribute = 
       (DesignerCategoryAttribute)attributes[typeof(DesignerCategoryAttribute)];
    Console.WriteLine("The category of the designer for this class is: " + myAttribute.Category);
  
    return 0;
}

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

Remarks

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 DesignerCategoryAttribute class defines the following common categories:

Category	Description
Component	Designers that are used with components. The attribute is set to the constant member DesignerCategoryAttribute.Component.
Form	Designers that are used with forms. The attribute is set to the constant member DesignerCategoryAttribute.Form.
Designer	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 Attributes.

Constructors

DesignerCategoryAttribute()	Initializes a new instance of the DesignerCategoryAttribute class with an empty string ("").
DesignerCategoryAttribute(String)	Initializes a new instance of the DesignerCategoryAttribute class with the given category name.

Fields

Component	Specifies that a component marked with this category use a component designer. This field is read-only.
Default	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.

Properties

Category	Gets the name of the category.
TypeId	Gets a unique identifier for this attribute.

Methods

Equals(Object)	Returns whether the value of the given object is equal to the current DesignOnlyAttribute.
GetHashCode()	Returns the hash code for this instance.
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsDefaultAttribute()	Determines if this attribute is the default.
Match(Object)	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

See also

• Attribute
• DesignerAttribute