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DesignOnlyAttribute Class

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

System.Object
  System.Attribute
    System.ComponentModel.DesignOnlyAttribute

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

[AttributeUsageAttribute(AttributeTargets.All)]
public sealed class DesignOnlyAttribute : Attribute

The DesignOnlyAttribute type exposes the following members.

  NameDescription
Public methodDesignOnlyAttributeInitializes a new instance of the DesignOnlyAttribute class.
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  NameDescription
Public propertyIsDesignOnlyGets a value indicating whether a property can be set only at design time.
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
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  NameDescription
Public methodEqualsReturns whether the value of the given object is equal to the current DesignOnlyAttribute. (Overrides Attribute.Equals(Object).)
Public methodGetHashCodeReturns the hash code for this instance. (Overrides Attribute.GetHashCode().)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeDetermines if this attribute is the default. (Overrides Attribute.IsDefaultAttribute().)
Public methodMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Public fieldStatic memberDefaultSpecifies the default value for the DesignOnlyAttribute, which is No. This static field is read-only.
Public fieldStatic memberNoSpecifies that a property can be set at design time or at run time. This static field is read-only.
Public fieldStatic memberYesSpecifies that a property can be set only at design time. This static field is read-only.
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  NameDescription
Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
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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.

[DesignOnly(true)]
 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 = 
    TypeDescriptor.GetProperties(this)["GetLanguage"].Attributes;

 /* Prints whether the property is marked as DesignOnly 
  * by retrieving the DesignOnlyAttribute from the AttributeCollection. */
 DesignOnlyAttribute myAttribute = 
    (DesignOnlyAttribute)attributes[typeof(DesignOnlyAttribute)];
 Console.WriteLine("This property is design only :" +
    myAttribute.IsDesignOnly.ToString());

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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.

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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