RegistryKey.GetValue Method (String)
Retrieves the value associated with the specified name. Returns null if the name/value pair does not exist in the registry.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- name
- Type: System.String
The name of the value to retrieve. This string is not case-sensitive.
| Exception | Condition |
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| SecurityException |
The user does not have the permissions required to read from the registry key. |
| ObjectDisposedException |
The RegistryKey that contains the specified value is closed (closed keys cannot be accessed). |
| IOException |
The RegistryKey that contains the specified value has been marked for deletion. |
| UnauthorizedAccessException |
The user does not have the necessary registry rights. |
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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 retrieve this unnamed value, specify either null or the empty string ("") for name. |
When the GetValue method retrieves expandable string values (RegistryValueKind.ExpandString), it expands environment strings using data from the local environment. To retrieve expandable string values from the registry on a remote computer, use the GetValue(String, Object, RegistryValueOptions) method overload to specify that you do not want environment strings expanded.
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If a value containing expandable references to environment variables has been stored as a string (RegistryValueKind.String), rather than as an expandable string (RegistryValueKind.ExpandString), GetValue does not expand it. You can expand such a string after it has been retrieved by calling the ExpandEnvironmentVariables method. |
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The recommended way to retrieve data from the PerformanceData key is to use the PerformanceCounter class rather than the RegistryKey.GetValue method. GetValue does not support reading values of type REG_NONE or REG_LINK. In both cases, the default value (null) is returned instead of the actual value. |
The following code 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 retrieve the corresponding registry data types.
using System; using Microsoft.Win32; public class Example { public static void Main() { // Delete and recreate the test key. Registry.CurrentUser.DeleteSubKey("RegistryValueKindExample", false); RegistryKey rk = Registry.CurrentUser.CreateSubKey("RegistryValueKindExample"); // Create name/value pairs. // This overload supports QWord (long) values. rk.SetValue("QuadWordValue", 42, RegistryValueKind.QWord); // The following SetValue calls have the same effect as using the // SetValue overload that does not specify RegistryValueKind. // rk.SetValue("DWordValue", 42, RegistryValueKind.DWord); rk.SetValue("MultipleStringValue", new string[] {"One", "Two", "Three"}, RegistryValueKind.MultiString); rk.SetValue("BinaryValue", new byte[] {10, 43, 44, 45, 14, 255}, RegistryValueKind.Binary); rk.SetValue("StringValue", "The path is %PATH%", RegistryValueKind.String); // This overload supports setting expandable string values. Compare // the output from this value with the previous string value. rk.SetValue("ExpandedStringValue", "The path is %PATH%", RegistryValueKind.ExpandString); // Display all name/value pairs stored in the test key, with each // registry data type in parentheses. // string[] valueNames = rk.GetValueNames(); foreach (string s in valueNames) { RegistryValueKind rvk = rk.GetValueKind(s); switch (rvk) { case RegistryValueKind.MultiString : string[] values = (string[]) rk.GetValue(s); Console.Write("\r\n {0} ({1}) =", s, rvk); for (int i = 0; i < values.Length; i++) { if (i != 0) Console.Write(","); Console.Write(" \"{0}\"", values[i]); } Console.WriteLine(); break; case RegistryValueKind.Binary : byte[] bytes = (byte[]) rk.GetValue(s); Console.Write("\r\n {0} ({1}) =", s, rvk); for (int i = 0; i < bytes.Length; i++) { // Display each byte as two hexadecimal digits. Console.Write(" {0:X2}", bytes[i]); } Console.WriteLine(); break; default : Console.WriteLine("\r\n {0} ({1}) = {2}", s, rvk, rk.GetValue(s)); break; } } } } /* This code example produces the following output: QuadWordValue (QWord) = 42 DWordValue (DWord) = 42 MultipleStringValue (MultiString) =, "One", "Two", "Three" BinaryValue (Binary) = 0A 2B 2C 2D 0E FF StringValue (String) = The path is %PATH% ExpandedStringValue (ExpandString) = The path is C:\Program Files\Microsoft.NET\SDK\v2.0\Bin; [***The remainder of this output is omitted.***] */
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RegistryPermission
to read from the registry. Associated enumeration: RegistryPermissionAccess.Read
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EnvironmentPermission
to read a registry key of type REG_EXPAND_SZ. Associated enumeration: PermissionState.Unrestricted
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.
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