DefaultSettingValueAttribute Class

Reference

Definition

Namespace:: System.Configuration

Assembly:: System.Configuration.ConfigurationManager.dll

Assembly:: System.dll

Package:: System.Configuration.ConfigurationManager v10.0.0-preview.1.25080.5

Source:: DefaultSettingValueAttribute.cs

Source:: DefaultSettingValueAttribute.cs

Source:: DefaultSettingValueAttribute.cs

Source:: DefaultSettingValueAttribute.cs

Source:: DefaultSettingValueAttribute.cs

Source:: DefaultSettingValueAttribute.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Specifies the default value for an application settings property.

public ref class DefaultSettingValueAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Property)]
public sealed class DefaultSettingValueAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Property)>]
type DefaultSettingValueAttribute = class
    inherit Attribute

Public NotInheritable Class DefaultSettingValueAttribute
Inherits Attribute

Inheritance: Object

Attribute
DefaultSettingValueAttribute

Attributes: AttributeUsageAttribute

Examples

The following code example demonstrates the use of the DefaultSettingValueAttribute applied to three of the four properties of the FormSettings wrapper class, which is derived from the ApplicationSettingsBase class. This class is used to persist the location, size, background color, and text of form. The first three of these form properties have default values associated with them.

The full code example is listed in the ApplicationSettingsBase class overview.

//Application settings wrapper class
ref class FormSettings sealed: public ApplicationSettingsBase
{
public:
    [UserScopedSettingAttribute()]
    property String^ FormText
    {
        String^ get()
        {
            return (String^)this["FormText"];
        }
        void set( String^ value )
        {
            this["FormText"] = value;
        }
    }

public:
    [UserScopedSettingAttribute()]
    [DefaultSettingValueAttribute("0, 0")]
    property Point FormLocation
    {
        Point get()
        {
            return (Point)(this["FormLocation"]);
        }
        void set( Point value )
        {
            this["FormLocation"] = value;
        }
    }

public:
    [UserScopedSettingAttribute()]
    [DefaultSettingValueAttribute("225, 200")]
    property Size FormSize
    {
        Size get()
        {
            return (Size)this["FormSize"];
        }
        void set( Size value )
        {
            this["FormSize"] = value;
        }
    }

public:
    [UserScopedSettingAttribute()]
    [DefaultSettingValueAttribute("LightGray")]
    property Color FormBackColor
    {
        Color get()
        {
            return (Color)this["FormBackColor"];
        }
        void set(Color value)
        {
            this["FormBackColor"] = value;
        }
    }

};

//Application settings wrapper class
sealed class FormSettings : ApplicationSettingsBase
{
    [UserScopedSettingAttribute()]
    public String FormText
    {
        get { return (String)this["FormText"]; }
        set { this["FormText"] = value; }
    }

    [UserScopedSettingAttribute()]
    [DefaultSettingValueAttribute("0, 0")]
    public Point FormLocation
    {
        get { return (Point)(this["FormLocation"]); }
        set { this["FormLocation"] = value; }
    }

    [UserScopedSettingAttribute()]
    [DefaultSettingValueAttribute("225, 200")]
    public Size FormSize
    {
        get { return (Size)this["FormSize"]; }
        set { this["FormSize"] = value; }
    }

    [UserScopedSettingAttribute()]
    [DefaultSettingValueAttribute("LightGray")]
    public Color FormBackColor
    {
        get { return (Color)this["FormBackColor"]; }
        set { this["FormBackColor"] = value; }
    }
}

'Application settings wrapper class. This class defines the settings we intend to use in our application.
NotInheritable Class FormSettings
    Inherits ApplicationSettingsBase

    <UserScopedSettingAttribute()> _
    Public Property FormText() As String
        Get
            Return CStr(Me("FormText"))
        End Get
        Set(ByVal value As String)
            Me("FormText") = value
        End Set
    End Property

    <UserScopedSettingAttribute(), DefaultSettingValueAttribute("0, 0")> _
    Public Property FormLocation() As Point
        Get
            Return CType(Me("FormLocation"), Point)
        End Get
        Set(ByVal value As Point)
            Me("FormLocation") = value
        End Set
    End Property

    <UserScopedSettingAttribute(), DefaultSettingValueAttribute("225, 200")> _
    Public Property FormSize() As Size
        Get
            Return CType(Me("FormSize"), Size)
        End Get
        Set(ByVal value As Size)
            Me("FormSize") = value
        End Set
    End Property

    <UserScopedSettingAttribute(), DefaultSettingValueAttribute("LightGray")> _
    Public Property FormBackColor() As Color
        Get
            Return CType(Me("FormBackColor"), Color)
        End Get
        Set(ByVal value As Color)
            Me("FormBackColor") = value
        End Set
    End Property
End Class

Remarks

重要

DefaultSettingValueAttribute can only be applied to individual settings properties; it is invalid to apply this attribute to an entire application settings class.

Different settings providers may have different requirements or limitations on the use of the DefaultSettingValueAttribute. For example, the LocalFileSettingsProvider does not require this attribute, and will override any value provided by this attribute if there are any values - default or user-modified - already present in the data store.

DefaultSettingValueAttribute requires that the default value can be represented as a string. As a result, settings using XML serialization cannot have a default value specified by means of this attribute. Some providers may choose to support multiple serialization schemes which can be specified at compile time using the SettingsSerializeAsAttribute.

注意事項

The default values specified by this attribute are stored as plain text in the resultant compiled .exe or .dll file. Therefore these default values are inherently insecure.

Constructors

DefaultSettingValueAttribute(String)

Initializes an instance of the DefaultSettingValueAttribute class.

Properties

TypeId	When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)
Value	Gets the default value for the application settings property.

Methods

Equals(Object)	Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute)
GetHashCode()	Returns the hash code for this instance. (Inherited from Attribute)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsDefaultAttribute()	When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute)
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)

Explicit Interface Implementations

_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)	Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute)
_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)
_Attribute.GetTypeInfoCount(UInt32)	Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute)
_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)	Provides access to properties and methods exposed by an object. (Inherited from Attribute)

Applies to

製品	バージョン
.NET	8 (package-provided), 9 (package-provided), 10 (package-provided)
.NET Framework	2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	2.0 (package-provided)
Windows Desktop	3.0, 3.1, 5, 6, 7, 8, 9, 10

次の方法で共有