DesignOnlyAttribute Class


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Specifies whether a property can only be set at design time.

Namespace:   System.ComponentModel
Assembly:  System (in System.dll)


public sealed class DesignOnlyAttribute : Attribute


Initializes a new instance of the DesignOnlyAttribute class.


Gets a value indicating whether a property can be set only at design time.


When implemented in a derived class, gets a unique identifier for this Attribute.(Inherited from Attribute.)


Returns whether the value of the given object is equal to the current DesignOnlyAttribute.(Overrides Attribute.Equals(Object).)


Returns the hash code for this instance.(Overrides Attribute.GetHashCode().)


Gets the Type of the current instance.(Inherited from Object.)


Determines if this attribute is the default.(Overrides Attribute.IsDefaultAttribute().)


When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.(Inherited from Attribute.)


Returns a string that represents the current object.(Inherited from Object.)


Specifies the default value for the DesignOnlyAttribute, which is No. This static field is read-only.


Specifies that a property can be set at design time or at run time. This static field is read-only.


Specifies that a property can be set only at design time. This static field is read-only.

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

Maps a set of names to a corresponding set of dispatch identifiers.(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

Retrieves the type information for an object, which can be used to get the type information for an interface.(Inherited from Attribute.)


Retrieves the number of type information interfaces that an object provides (either 0 or 1).(Inherited from Attribute.)

System_CAPS_pubinterfaceSystem_CAPS_privmethod_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

Provides access to properties and methods exposed by an object.(Inherited from Attribute.)

Members marked with the DesignOnlyAttribute set to true can be set only at design time. Typically, these properties exist only at design time and do not correspond to a real property on the object at run time.

Members that either have no attribute or are marked with the DesignOnlyAttribute set to false can be set during run time. The default is false.

A property with the DesignOnlyAttribute set to true has its value serialized to the .resx file instead of the InitializeComponent method.

For more information, see Extending Metadata Using Attributes.

The following example creates a GetLanguage property. The property is marked with a DesignOnlyAttribute.

 public CultureInfo GetLanguage {
    get {
       // Insert code here.
       return myCultureInfo;
    set {
       // Insert code here.

The next example gets the value of the DesignOnlyAttribute. First the code gets a PropertyDescriptorCollection with all the properties for the object. Next it indexes into the PropertyDescriptorCollection to find the GetLanguage property. Then it returns the attributes for this property and saves them in the attributes variable.

The example then prints whether the property is design only by retrieving DesignOnlyAttribute from the AttributeCollection, and writing it to the console screen.

// Gets the attributes for the property.
 AttributeCollection attributes = 

 /* Prints whether the property is marked as DesignOnly 
  * by retrieving the DesignOnlyAttribute from the AttributeCollection. */
 DesignOnlyAttribute myAttribute = 
 Console.WriteLine("This property is design only :" +

.NET Framework
Available since 1.1

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

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