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RegistryKey.SetValue Method (String, Object)

Sets the specified name/value pair.

Namespace:  Microsoft.Win32
Assembly:  mscorlib (in mscorlib.dll)

member SetValue : 
        name:string * 
        value:Object -> unit 


Type: System.String
The name of the value to store.
Type: System.Object
The data to be stored.


value is a null reference (Nothing in Visual Basic).


value is an unsupported data type.


The RegistryKey that contains the specified value is closed (closed keys cannot be accessed).


The RegistryKey is read-only, and cannot be written to; for example, the key has not been opened with write access.


The RegistryKey object represents a root-level node, and the operating system is Windows Millennium Edition or Windows 98.


The user does not have the permissions required to create or modify registry keys.


The RegistryKey object represents a root-level node, and the operating system is Windows 2000, Windows XP, or Windows Server 2003.

Because many values can be stored in each key in the registry, you must use the name parameter to specify the particular value you want to set.


A registry key can have one value that is not associated with any name. When this unnamed value is displayed in the registry editor, the string "(Default)" appears instead of a name. To set this unnamed value, specify either a null reference (Nothing in Visual Basic) or the empty string ("") for name.

In order to set values in a key, you must open the key with write access. After you have opened a key with write access, you can change any of the name/value pairs in that key.

If the specified name does not exist in the key, it is created and the associated value is set to value.

This overload of SetValue stores 64-bit integers as strings (RegistryValueKind.String). To store 64-bit numbers as RegistryValueKind.QWord values, use the SetValue(String, Object, RegistryValueKind) overload that specifies RegistryValueKind.

This overload of SetValue stores all string values as RegistryValueKind.String, even if they contain expandable references to environment variables. To save string values as expandable strings (RegistryValueKind.ExpandString), use the SetValue(String, Object, RegistryValueKind) overload that specifies RegistryValueKind.

Numeric types other than 32-bit integers are stored as strings by this method overload. Enumeration elements are stored as strings containing the element names.

Caution noteCaution

Do not expose RegistryKey objects in such a way that a malicious program could create thousands of meaningless subkeys or key/value pairs. For example, do not allow callers to enter arbitrary keys or values.


On Windows 98 and Windows Millennium Edition the registry is not Unicode, and not all Unicode characters are valid for all code pages. A Unicode character that is invalid for the current code page is replaced by the best available match. No exception is thrown.

The following code example shows how the SetValue method determines the registry data type when it sets values. The example creates a test key and adds values of different data types to the key. The example then reads the name/value pairs and displays them to the console, using the GetValueKind method to display the corresponding registry data types.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.