# List of data types of the Standard Libraries

This is a list of data types of the Standard Libraries as defined in the ECMA-335 standard. Implementations of the Common Language Infrastructure must define the types of the standard in their respective standard libraries. The standard encourages implementers to extend or to modify the types specified in the standard to provide additional functionality.

## List
### Base Class Library

| Name | Namespace | Base type | CIL type | Assembly name | Assembly version |
| Action | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Action<T> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Action<T1, T2> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Action<T1, T2, T3> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Action<T1, T2, T3, T4> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Action<T1, T2, T3, T4, T5> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Action<T1, T2, T3, T4, T5, T6> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Action<T1, T2, T3, T4, T5, T6, T7> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Action<T1, T2, T3, T4, T5, T6, T7, T8> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| ApplicationException | System | System.Exception | class | mscorlib | 2.0.x.x |
| ArgumentException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| ArgumentNullException | System | System.ArgumentException | class | mscorlib | 2.0.x.x |
| ArgumentOutOfRangeException | System | System.ArgumentException | class | mscorlib | 2.0.x.x |
| ArithmeticException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| Array | System | System.Object | class | mscorlib | 2.0.x.x |
| ArrayList | System.Collections | System.Object | class | mscorlib | 2.0.x.x |
| ArrayTypeMismatchException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| ASCIIEncoding | System.Text | System.Text.Encoding | class | mscorlib | 2.0.x.x |
| AsyncCallback | System | System.Delegate | delegate | mscorlib | 2.0.x.x |
| Attribute | System | System.Object | class | mscorlib | 2.0.x.x |
| AttributeTargets | System | System.Enum | enumeration | mscorlib | 2.0.x.x |
| AttributeUsageAttribute | System | System.Attribute | class | mscorlib | 2.0.x.x |
| AutoResetEvent | System.Threading | System.Threading.EventWaitHandle | class | mscorlib | 4.0.0.0 |
| Boolean | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| Byte | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| Char | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| CharEnumerator | System | System.Object | class | mscorlib | 2.0.x.x |
| CLSCompliantAttribute | System | System.Attribute | class | mscorlib | 2.0.x.x |
| CodeAccessPermission | System.Security | System.Object | class | mscorlib | 2.0.x.x |
| CodeAccessSecurityAttribute | System.Security.Permissions | System.Security.Permissions.SecurityAttribute | class | mscorlib | 2.0.x.x |
| Comparer | System.Collections | System.Object | class | mscorlib | 2.0.x.x |
| Comparer<T> | System.Collections.Generic | System.Object | class | mscorlib | 4.0.0.0 |
| Comparison<T> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| ConditionalAttribute | System.Diagnostics | System.Attribute | class | mscorlib | 2.0.x.x |
| Console | System | System.Object | class | mscorlib | 2.0.x.x |
| Convert | System | System.Object | class | mscorlib | 2.0.x.x |
| Converter<TInput, TOutput> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| DateTime | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| DateTimeFormatInfo | System.Globalization | System.Object | class | mscorlib | 2.0.x.x |
| DateTimeStyles | System.Globalization | System.Enum | enumeration | mscorlib | 2.0.x.x |
| DBNull | System | System.Object | class | mscorlib | 4.0.0.0 |
| Decoder | System.Text | System.Object | class | mscorlib | 2.0.x.x |
| Delegate | System | System.Object | class | mscorlib | 2.0.x.x |
| Dictionary<TKey, TValue> | System.Collections.Generic | System.Object | class | mscorlib | 2.0.x.x |
| Dictionary<TKey, TValue>.Enumerator | System.Collections.Generic | System.ValueType | structure | mscorlib | 2.0.x.x |
| Dictionary<TKey, TValue>.KeyCollection | System.Collections.Generic | System.Object | class | mscorlib | 2.0.x.x |
| Dictionary<TKey, TValue>.KeyCollection.Enumerator | System.Collections.Generic | System.ValueType | structure | mscorlib | 2.0.x.x |
| Dictionary<TKey, TValue>.ValueCollection | System.Collections.Generic | System.Object | class | mscorlib | 2.0.x.x |
| Dictionary<TKey, TValue>.ValueCollection.Enumerator | System.Collections.Generic | System.ValueType | structure | mscorlib | 2.0.x.x |
| DictionaryEntry | System.Collections | System.ValueType | structure | mscorlib | 2.0.x.x |
| Directory | System.IO | System.Object | class | mscorlib | 2.0.x.x |
| DirectoryNotFoundException | System.IO | System.IO.IOException | class | mscorlib | 2.0.x.x |
| DivideByZeroException | System | System.ArithmeticException | class | mscorlib | 2.0.x.x |
| DuplicateWaitObjectException | System | System.ArgumentException | class | mscorlib | 2.0.x.x |
| Encoder | System.Text | System.Object | class | mscorlib | 2.0.x.x |
| Encoding | System.Text | System.Object | class | mscorlib | 2.0.x.x |
| EndOfStreamException | System.IO | System.IO.IOException | class | mscorlib | 2.0.x.x |
| Enum | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| Environment | System | System.Object | class | mscorlib | 2.0.x.x |
| EnvironmentPermission | System.Security.Permissions | System.Security.CodeAccessPermission | class | mscorlib | 2.0.x.x |
| EnvironmentPermissionAccess | System.Security.Permissions | System.Enum | enumeration | mscorlib | 2.0.x.x |
| EnvironmentPermissionAttribute | System.Security.Permissions | System.Security.Permissions.CodeAccessSecurityAttribute | class | mscorlib | 2.0.x.x |
| EqualityComparer<T> | System.Collections.Generic | System.Object | class | mscorlib | 4.0.0.0 |
| EventArgs | System | System.Object | class | mscorlib | 2.0.x.x |
| EventHandler | System | System.Delegate | delegate | mscorlib | 2.0.x.x |
| EventResetMode | System.Threading | System.Enum | enumeration | mscorlib | 4.0.0.0 |
| EventWaitHandle | System.Threading | System.Threading.WaitHandle | class | mscorlib | 4.0.0.0 |
| Exception | System | System.Object | class | mscorlib | 2.0.x.x |
| ExecutionEngineException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| File | System.IO | System.Object | class | mscorlib | 2.0.x.x |
| FileAccess | System.IO | System.Enum | enumeration | mscorlib | 2.0.x.x |
| FileIOPermissionAccess | System.Security.Permissions | System.Enum | enumeration | mscorlib | 2.0.x.x |
| FileIOPermissionAttribute | System.Security.Permissions | System.Security.Permissions.CodeAccessSecurityAttribute | class | mscorlib | 2.0.x.x |
| FileLoadException | System.IO | System.IO.IOException | class | mscorlib | 2.0.x.x |
| FileMode | System.IO | System.Enum | enumeration | mscorlib | 2.0.x.x |
| FileNotFoundException | System.IO | System.IO.IOException | class | mscorlib | 2.0.x.x |
| FileShare | System.IO | System.Enum | enumeration | mscorlib | 2.0.x.x |
| FileStream | System.IO | System.IO.Stream | class | mscorlib | 2.0.x.x |
| FlagsAttribute | System | System.Attribute | class | mscorlib | 2.0.x.x |
| FormatException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| Func<TResult> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Func<T, TResult> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Func<T1, T2, TResult> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Func<T1, T2, T3, TResult> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Func<T1, T2, T3, T4, TResult> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Func<T1, T2, T3, T4, T5, TResult> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Func<T1, T2, T3, T4, T5, T6, TResult> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Func<T1, T2, T3, T4, T5, T6, T7, TResult> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Func<T1, T2, T3, T4, T5, T6, T7, T8, TResult> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| GC | System | System.Object | class | mscorlib | 2.0.x.x |
| Guid | System | System.ValueType | structure | mscorlib | 4.0.0.0 |
| Hashtable | System.Collections | System.Object | class | mscorlib | 2.0.x.x |
| IAsyncResult | System | none | interface | mscorlib | 2.0.x.x |
| ICloneable | System | none | interface | mscorlib | 2.0.x.x |
| ICollection | System.Collections | none | interface | mscorlib | 2.0.x.x |
| ICollection<T> | System.Collections.Generic | none | interface | mscorlib | 2.0.x.x |
| IComparable | System | none | interface | mscorlib | 2.0.x.x |
| IComparable<T> | System | none | interface | mscorlib | 4.0.0.0 |
| IComparer | System.Collections | none | interface | mscorlib | 2.0.x.x |
| IComparer<T> | System.Collections.Generic | none | interface | mscorlib | 4.0.0.0 |
| IDictionary | System.Collections | none | interface | mscorlib | 2.0.x.x |
| IDictionary<TKey, TValue> | System.Collections.Generic | none | interface | mscorlib | 2.0.x.x |
| IDictionaryEnumerator | System.Collections | none | interface | mscorlib | 2.0.x.x |
| IDisposable | System | none | interface | mscorlib | 2.0.x.x |
| IEnumerable | System.Collections | none | interface | mscorlib | 2.0.x.x |
| IEnumerable<T> | System.Collections.Generic | none | interface | mscorlib | 4.0.0.0 |
| IEnumerator | System.Collections | none | interface | mscorlib | 2.0.x.x |
| IEnumerator<T> | System.Collections.Generic | none | interface | mscorlib | 2.0.x.x |
| IEqualityComparer<T> | System.Collections.Generic | none | interface | mscorlib | 4.0.0.0 |
| IEquatable<T> | System | none | interface | mscorlib | 2.0.x.x |
| IFormatProvider | System | none | interface | mscorlib | 2.0.x.x |
| IFormattable | System | none | interface | mscorlib | 2.0.x.x |
| IHashCodeProvider | System.Collections | none | interface | mscorlib | 2.0.x.x |
| IList | System.Collections | none | interface | mscorlib | 2.0.x.x |
| IList<T> | System.Collections.Generic | none | interface | mscorlib | 2.0.x.x |
| IndexOutOfRangeException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| Int16 | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| Int32 | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| Int64 | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| Interlocked | System.Threading | System.Object | class | mscorlib | 2.0.x.x |
| INullableValue | System | none | interface | mscorlib | 2.0.x.x |
| InvalidCastException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| InvalidOperationException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| InvalidProgramException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| IOException | System.IO | System.SystemException | class | mscorlib | 2.0.x.x |
| IPermission | System.Security | none | interface | mscorlib | 2.0.x.x |
| ISet<T> | System.Collections.Generic | none | interface | System | 4.0.0.0 |
| KeyNotFoundException | System.Collections.Generic | System.SystemException | class | mscorlib | 2.0.x.x |
| KeyValuePair<K, V> | System.Collections.Generic | System.ValueType | structure | mscorlib | 2.0.x.x |
| LinkedList<T> | System.Collections.Generic | System.Object | class | System | 4.0.0.0 |
| LinkedList<T>.Enumerator | System.Collections.Generic | System.ValueType | structure | System | 4.0.0.0 |
| LinkedListNode<T> | System.Collections.Generic | System.Object | class | System | 4.0.0.0 |
| List<T> | System.Collections.Generic | System.Object | class | mscorlib | 2.0.x.x |
| List<T>.Enumerator | System.Collections.Generic | System.ValueType | structure | mscorlib | 2.0.x.x |
| ManualResetEvent | System.Threading | System.Threading.EventWaitHandle | class | mscorlib | 4.0.0.0 |
| MarshalByRefObject | System | System.Object | class | mscorlib | 2.0.x.x |
| MemoryStream | System.IO | System.IO.Stream | class | mscorlib | 2.0.x.x |
| Monitor | System.Threading | System.Object | class | mscorlib | 2.0.x.x |
| MulticastDelegate | System | System.Delegate | delegate | mscorlib | 4.0.0.0 |
| NotImplementedException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| NotSupportedException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| Nullable<T> | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| NullReferenceException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| NumberFormatInfo | System.Globalization | System.Object | class | mscorlib | 2.0.x.x |
| NumberStyles | System.Globalization | System.Enum | enumeration | mscorlib | 2.0.x.x |
| Object | System | root | class | mscorlib | 2.0.x.x |
| ObjectDisposedException | System | System.InvalidOperationException | class | mscorlib | 2.0.x.x |
| ObsoleteAttribute | System | System.Attribute | class | mscorlib | 2.0.x.x |
| OutOfMemoryException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| OverflowException | System | System.ArithmeticException | class | mscorlib | 2.0.x.x |
| Path | System.IO | System.Object | class | mscorlib | 2.0.x.x |
| PathTooLongException | System.IO | System.IO.IOException | class | mscorlib | 2.0.x.x |
| PermissionSet | System.Security | System.Object | class | mscorlib | 2.0.x.x |
| PermissionState | System.Security.Permissions | System.Enum | enumeration | mscorlib | 2.0.x.x |
| Predicate<T> | System | System.MulticastDelegate | delegate | mscorlib | 4.0.0.0 |
| Queue<T> | System.Collections.Generic | System.Object | class | System | 4.0.0.0 |
| Random | System | System.Object | class | mscorlib | 2.0.x.x |
| RankException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| SByte | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| SecurityAction | System.Security.Permissions | System.Enum | enumeration | mscorlib | 2.0.x.x |
| SecurityAttribute | System.Security.Permissions | System.Attribute | class | mscorlib | 2.0.x.x |
| SecurityElement | System.Security | System.Object | class | mscorlib | 2.0.x.x |
| SecurityException | System.Security | System.SystemException | class | mscorlib | 2.0.x.x |
| SecurityPermission | System.Security.Permissions | System.Security.CodeAccessPermission | class | mscorlib | 2.0.x.x |
| SecurityPermissionAttribute | System.Security.Permissions | System.Security.Permissions.CodeAccessSecurityAttribute | class | mscorlib | 2.0.x.x |
| SecurityPermissionFlag | System.Security.Permissions | System.Enum | enumeration | mscorlib | 2.0.x.x |
| SeekOrigin | System.IO | System.Enum | enumeration | mscorlib | 2.0.x.x |
| Stack | System.Collections | System.Object | class | mscorlib | 4.0.0.0 |
| Stack<T>.Enumerator | System.Collections.Generic | System.ValueType | structure | System | 4.0.0.0 |
| Stack<T> | System.Collections.Generic | System.Object | class | System | 4.0.0.0 |
| StackOverflowException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| Stream | System.IO | System.MarshalByRefObject | class | mscorlib | 2.0.x.x |
| StreamReader | System.IO | System.IO.TextReader | class | mscorlib | 2.0.x.x |
| StreamWriter | System.IO | System.IO.TextWriter | class | mscorlib | 2.0.x.x |
| String | System | System.Object | class | mscorlib | 2.0.x.x |
| StringBuilder | System.Text | System.Object | class | mscorlib | 2.0.x.x |
| StringReader | System.IO | System.IO.TextReader | class | mscorlib | 2.0.x.x |
| StringWriter | System.IO | System.IO.TextWriter | class | mscorlib | 2.0.x.x |
| SynchronizationLockException | System.Threading | System.SystemException | class | mscorlib | 2.0.x.x |
| SystemException | System | System.Exception | class | mscorlib | 2.0.x.x |
| TextReader | System.IO | System.MarshalByRefObject | class | mscorlib | 2.0.x.x |
| TextWriter | System.IO | System.MarshalByRefObject | class | mscorlib | 2.0.x.x |
| Thread | System.Threading | System.Object | class | mscorlib | 2.0.x.x |
| ThreadAbortException | System.Threading | System.SystemException | class | mscorlib | 2.0.x.x |
| ThreadPriority | System.Threading | System.Enum | enumeration | mscorlib | 2.0.x.x |
| ThreadStart | System.Threading | System.Delegate | delegate | mscorlib | 2.0.x.x |
| ThreadState | System.Threading | System.Enum | enumeration | mscorlib | 2.0.x.x |
| ThreadStateException | System.Threading | System.SystemException | class | mscorlib | 2.0.x.x |
| ThreadStaticAttribute | System | System.Attribute | class | mscorlib | 2.0.x.x |
| Timeout | System.Threading | System.Object | class | mscorlib | 2.0.x.x |
| Timer | System.Threading | System.MarshalByRefObject | class | mscorlib | 2.0.x.x |
| TimerCallback | System.Threading | System.Delegate | delegate | mscorlib | 2.0.x.x |
| TimeSpan | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| Type | System | System.Object | class | mscorlib | 2.0.x.x |
| TypeInitializationException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| UInt16 | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| UInt32 | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| UInt64 | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| UnauthorizedAccessException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| UnicodeCategory | System.Globalization | System.Enum | enumeration | mscorlib | 2.0.x.x |
| UnicodeEncoding | System.Text | System.Text.Encoding | class | mscorlib | 2.0.x.x |
| UTF8Encoding | System.Text | System.Text.Encoding | class | mscorlib | 2.0.x.x |
| ValueType | System | System.Object | class | mscorlib | 2.0.x.x |
| VerificationException | System.Security | System.SystemException | class | mscorlib | 2.0.x.x |
| Version | System | System.Object | class | mscorlib | 2.0.x.x |
| WaitHandle | System.Threading | System.MarshalByRefObject | class | mscorlib | 2.0.x.x |
| WeakReference | System | System.Object | class | mscorlib | 4.0.0.0 |

### Runtime Infrastructure Library

| Name | Namespace | Base type | CIL type | Assembly name | Assembly version |
| AppDomain | System | System.MarshalByRefObject | class | mscorlib | 2.0.x.x |
| Assembly | System.Reflection | System.Object | class | mscorlib | 2.0.x.x |
| AssemblyLoadEventArgs | System | System.EventArgs | class | mscorlib | 2.0.x.x |
| AssemblyLoadEventHandler | System | System.Delegate | delegate | mscorlib | 2.0.x.x |
| BadImageFormatException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| CallingConvention | System.Runtime.InteropServices | System.Enum | enumeration | mscorlib | 2.0.x.x |
| CallingConventions | System.Reflection | System.Enum | enumeration | mscorlib | 4.0.0.0 |
| CannotUnloadAppDomainException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| CharSet | System.Runtime.InteropServices | System.Enum | enumeration | mscorlib | 2.0.x.x |
| CompilationRelaxations | System.Runtime.CompilerServices | System.Enum | enumeration | mscorlib | 2.0.x.x |
| CompilationRelaxationsAttribute | System.Runtime.CompilerServices | System.Attribute | class | mscorlib | 2.0.x.x |
| DecimalConstantAttribute | System.Runtime.CompilerServices | System.Attribute | class | mscorlib | 2.0.x.x |
| DefaultMemberAttribute | System.Reflection | System.Attribute | class | mscorlib | 2.0.x.x |
| DllImportAttribute | System.Runtime.InteropServices | System.Attribute | class | mscorlib | 2.0.x.x |
| EntryPointNotFoundException | System | System.TypeLoadException | class | mscorlib | 2.0.x.x |
| FieldAccessException | System | System.MemberAccessException | class | mscorlib | 2.0.x.x |
| FieldOffsetAttribute | System.Runtime.InteropServices | System.Attribute | class | mscorlib | 2.0.x.x |
| GCHandle | System.Runtime.InteropServices | System.ValueType | structure | mscorlib | 2.0.x.x |
| GCHandleType | System.Runtime.InteropServices | System.Enum | enumeration | mscorlib | 2.0.x.x |
| GuidAttribute | System.Runtime.InteropServices | System.Attribute | class | mscorlib | 4.0.0.0 |
| InAttribute | System.Runtime.InteropServices | System.Attribute | class | mscorlib | 2.0.x.x |
| IndexerNameAttribute | System.Runtime.CompilerServices | System.Attribute | class | mscorlib | 2.0.x.x |
| IntPtr | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| IsVolatile | System.Runtime.CompilerServices | System.Object | class | mscorlib | 2.0.x.x |
| LayoutKind | System.Runtime.InteropServices | System.Enum | enumeration | mscorlib | 2.0.x.x |
| Marshal | System.Runtime.InteropServices | System.Object | class | mscorlib | 4.0.0.0 |
| MarshalAsAttribute | System.Runtime.InteropServices | System.Attribute | class | mscorlib | 2.0.x.x |
| MemberAccessException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| MethodAccessException | System | System.MemberAccessException | class | mscorlib | 2.0.x.x |
| MethodImplAttribute | System.Runtime.CompilerServices | System.Attribute | class | mscorlib | 2.0.x.x |
| MethodImplOptions | System.Runtime.CompilerServices | System.Enum | enumeration | mscorlib | 2.0.x.x |
| MissingFieldException | System | System.MissingMemberException | class | mscorlib | 2.0.x.x |
| MissingMemberException | System | System.MemberAccessException | class | mscorlib | 2.0.x.x |
| MissingMethodException | System | System.MissingMemberException | class | mscorlib | 2.0.x.x |
| OutAttribute | System.Runtime.InteropServices | System.Attribute | class | mscorlib | 2.0.x.x |
| ParamArrayAttribute | System | System.Attribute | class | mscorlib | 2.0.x.x |
| RuntimeFieldHandle | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| RuntimeHelpers | System.Runtime.CompilerServices | System.Object | class | mscorlib | 2.0.x.x |
| RuntimeMethodHandle | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| RuntimeTypeHandle | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| SafeBuffer | System.Runtime.InteropServices | System.Runtime.InteropServices.SafeHandle | class | mscorlib | 4.0.0.0 |
| SafeHandle | System.Runtime.InteropServices | System.Object | class | mscorlib | 4.0.0.0 |
| StructLayoutAttribute | System.Runtime.InteropServices | System.Attribute | class | mscorlib | 2.0.x.x |
| TypeForwardedFromAttribute | System.Runtime.CompilerServices | none | interface | mscorlib | 4.0.0.0 |
| TypeForwardedToAttribute | System.Runtime.CompilerServices | System.Attribute | class | mscorlib | 4.0.0.0 |
| TypeLoadException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| TypeUnloadedException | System | System.SystemException | class | mscorlib | 2.0.x.x |
| UIntPtr | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| UnhandledExceptionEventArgs | System | System.EventArgs | class | mscorlib | 2.0.x.x |
| UnhandledExceptionEventHandler | System | System.Delegate | delegate | mscorlib | 2.0.x.x |
| UnmanagedType | System.Runtime.InteropServices | System.Enum | enumeration | mscorlib | 2.0.x.x |

### Network Library

| Name | Namespace | Base type | CIL type | Assembly name | Assembly version |
| AddressFamily | System.Net.Sockets | System.Enum | enumeration | System | 2.0.x.x |
| AuthenticationManager | System.Net | System.Object | class | System | 2.0.x.x |
| Authorization | System.Net | System.Object | class | System | 2.0.x.x |
| CredentialCache | System.Net | System.Object | class | System | 2.0.x.x |
| Dns | System.Net | System.Object | class | System | 2.0.x.x |
| DnsPermission | System.Net | System.Security.CodeAccessPermission | class | System | 2.0.x.x |
| DnsPermissionAttribute | System.Net | System.Security.Permissions.CodeAccessSecurityAttribute | class | System | 2.0.x.x |
| EndPoint | System.Net | System.Object | class | System | 2.0.x.x |
| GlobalProxySelection | System.Net | System.Object | class | System | 2.0.x.x |
| HttpContinueDelegate | System.Net | System.Delegate | delegate | System | 2.0.x.x |
| HttpStatusCode | System.Net | System.Enum | enumeration | System | 2.0.x.x |
| HttpVersion | System.Net | System.Object | class | System | 2.0.x.x |
| HttpWebRequest | System.Net | System.Net.WebRequest | class | System | 2.0.x.x |
| HttpWebResponse | System.Net | System.Net.WebResponse | class | System | 2.0.x.x |
| IAuthenticationModule | System.Net | none | interface | System | 2.0.x.x |
| ICredentials | System.Net | none | interface | System | 2.0.x.x |
| IPAddress | System.Net | System.Object | class | System | 2.0.x.x |
| IPEndPoint | System.Net | System.Net.EndPoint | class | System | 2.0.x.x |
| IPHostEntry | System.Net | System.Object | class | System | 2.0.x.x |
| IWebProxy | System.Net | none | interface | System | 2.0.x.x |
| IWebRequestCreate | System.Net | none | interface | System | 2.0.x.x |
| LingerOption | System.Net.Sockets | System.Object | class | System | 2.0.x.x |
| MulticastOption | System.Net.Sockets | System.Object | class | System | 2.0.x.x |
| NameValueCollection | System.Collections.Specialized | System.Object | class | System | 2.0.x.x |
| NetworkAccess | System.Net | System.Enum | enumeration | System | 2.0.x.x |
| NetworkCredential | System.Net | System.Object | class | System | 2.0.x.x |
| NetworkStream | System.Net.Sockets | System.IO.Stream | class | System | 2.0.x.x |
| ProtocolType | System.Net.Sockets | System.Enum | enumeration | System | 2.0.x.x |
| ProtocolViolationException | System.Net | System.InvalidOperationException | class | System | 2.0.x.x |
| SelectMode | System.Net.Sockets | System.Enum | enumeration | System | 2.0.x.x |
| ServicePoint | System.Net | System.Object | class | System | 2.0.x.x |
| ServicePointManager | System.Net | System.Object | class | System | 2.0.x.x |
| Socket | System.Net.Sockets | System.Object | class | System | 2.0.x.x |
| SocketAddress | System.Net | System.Object | class | System | 2.0.x.x |
| SocketException | System.Net.Sockets | System.SystemException | class | System | 2.0.x.x |
| SocketFlags | System.Net.Sockets | System.Enum | enumeration | System | 2.0.x.x |
| SocketOptionLevel | System.Net.Sockets | System.Enum | enumeration | System | 2.0.x.x |
| SocketOptionName | System.Net.Sockets | System.Enum | enumeration | System | 2.0.x.x |
| SocketPermission | System.Net | System.Security.CodeAccessPermission | class | System | 2.0.x.x |
| SocketPermissionAttribute | System.Net | System.Security.Permissions.CodeAccessSecurityAttribute | class | System | 2.0.x.x |
| SocketShutdown | System.Net.Sockets | System.Enum | enumeration | System | 2.0.x.x |
| SocketType | System.Net.Sockets | System.Enum | enumeration | System | 2.0.x.x |
| TransportType | System.Net | System.Enum | enumeration | System | 2.0.x.x |
| Uri | System | System.Object | class | System | 2.0.x.x |
| UriBuilder | System | System.Object | class | System | 2.0.x.x |
| UriFormatException | System | System.FormatException | class | System | 2.0.x.x |
| UriHostNameType | System | System.Enum | enumeration | System | 2.0.x.x |
| UriPartial | System | System.Enum | enumeration | System | 2.0.x.x |
| WebClient | System.Net | System.MarshalByRefObject | class | System | 2.0.x.x |
| WebException | System.Net | System.InvalidOperationException | class | System | 2.0.x.x |
| WebExceptionStatus | System.Net | System.Enum | enumeration | System | 2.0.x.x |
| WebHeaderCollection | System.Net | System.Collections.Specialized.NameValueCollection | class | System | 2.0.x.x |
| WebPermission | System.Net | System.Security.CodeAccessPermission | class | System | 2.0.x.x |
| WebPermissionAttribute | System.Net | System.Security.Permissions.CodeAccessSecurityAttribute | class | System | 2.0.x.x |
| WebProxy | System.Net | System.Object | class | System | 2.0.x.x |
| WebRequest | System.Net | System.MarshalByRefObject | class | System | 2.0.x.x |
| WebResponse | System.Net | System.MarshalByRefObject | class | System | 2.0.x.x |

### Reflection Library

| Name | Namespace | Base type | CIL type | Assembly name | Assembly version |
| AmbiguousMatchException | System.Reflection | System.SystemException | class | mscorlib | 2.0.x.x |
| Binder | System.Reflection | System.Object | class | mscorlib | 2.0.x.x |
| BindingFlags | System.Reflection | System.Enum | enumeration | mscorlib | 2.0.x.x |
| ConstructorInfo | System.Reflection | System.Reflection.MethodBase | class | mscorlib | 2.0.x.x |
| CultureInfo | System.Globalization | System.Object | class | mscorlib | 2.0.x.x |
| EventAttributes | System.Reflection | System.Enum | enumeration | mscorlib | 2.0.x.x |
| EventInfo | System.Reflection | System.Reflection.MemberInfo | class | mscorlib | 2.0.x.x |
| FieldAttributes | System.Reflection | System.Enum | enumeration | mscorlib | 2.0.x.x |
| FieldInfo | System.Reflection | System.Reflection.MemberInfo | class | mscorlib | 2.0.x.x |
| GenericParameterAttributes | System.Reflection | System.Enum | enumeration | mscorlib | 2.0.x.x |
| MemberInfo | System.Reflection | System.Object | class | mscorlib | 2.0.x.x |
| MethodAttributes | System.Reflection | System.Enum | enumeration | mscorlib | 2.0.x.x |
| MethodBase | System.Reflection | System.Reflection.MemberInfo | class | mscorlib | 2.0.x.x |
| MethodInfo | System.Reflection | System.Reflection.MethodBase | class | mscorlib | 2.0.x.x |
| Module | System.Reflection | System.Object | class | mscorlib | 2.0.x.x |
| ParameterAttributes | System.Reflection | System.Enum | enumeration | mscorlib | 2.0.x.x |
| ParameterInfo | System.Reflection | System.Object | class | mscorlib | 2.0.x.x |
| ParameterModifier | System.Reflection | System.ValueType | structure | mscorlib | 2.0.x.x |
| PropertyAttributes | System.Reflection | System.Enum | enumeration | mscorlib | 2.0.x.x |
| PropertyInfo | System.Reflection | System.Reflection.MemberInfo | class | mscorlib | 2.0.x.x |
| ReflectionPermission | System.Security.Permissions | System.Security.CodeAccessPermission | class | mscorlib | 2.0.x.x |
| ReflectionPermissionAttribute | System.Security.Permissions | System.Security.Permissions.CodeAccessSecurityAttribute | class | mscorlib | 2.0.x.x |
| ReflectionPermissionFlag | System.Security.Permissions | System.Enum | enumeration | mscorlib | 2.0.x.x |
| TargetException | System.Reflection | System.ApplicationException | class | mscorlib | 2.0.x.x |
| TargetInvocationException | System.Reflection | System.ApplicationException | class | mscorlib | 2.0.x.x |
| TargetParameterCountException | System.Reflection | System.ApplicationException | class | mscorlib | 2.0.x.x |
| TypeAttributes | System.Reflection | System.Enum | enumeration | mscorlib | 2.0.x.x |
| Void | System | System.ValueType | structure | mscorlib | 2.0.x.x |

### XML Library

| Name | Namespace | Base type | CIL type | Assembly name | Assembly version |
| Formatting | System.Xml | System.Enum | enumeration | System.Xml | 2.0.x.x |
| NameTable | System.Xml | System.Xml.XmlNameTable | class | System.Xml | 2.0.x.x |
| ReadState | System.Xml | System.Enum | enumeration | System.Xml | 2.0.x.x |
| WhitespaceHandling | System.Xml | System.Enum | enumeration | System.Xml | 2.0.x.x |
| WriteState | System.Xml | System.Enum | enumeration | System.Xml | 2.0.x.x |
| XmlConvert | System.Xml | System.Object | class | System.Xml | 2.0.x.x |
| XmlException | System.Xml | System.SystemException | class | System.Xml | 2.0.x.x |
| XmlNamespaceManager | System.Xml | System.Object | class | System.Xml | 2.0.x.x |
| XmlNameTable | System.Xml | System.Object | class | System.Xml | 2.0.x.x |
| XmlNodeType | System.Xml | System.Enum | enumeration | System.Xml | 2.0.x.x |
| XmlParserContext | System.Xml | System.Object | class | System.Xml | 2.0.x.x |
| XmlReader | System.Xml | System.Object | class | System.Xml | 2.0.x.x |
| XmlResolver | System.Xml | System.Object | class | System.Xml | 2.0.x.x |
| XmlSpace | System.Xml | System.Enum | enumeration | System.Xml | 2.0.x.x |
| XmlTextReader | System.Xml | System.Xml.XmlReader | class | System.Xml | 2.0.x.x |
| XmlTextWriter | System.Xml | System.Xml.XmlWriter | class | System.Xml | 2.0.x.x |
| XmlUrlResolver | System.Xml | System.Xml.XmlResolver | class | System.Xml | 2.0.x.x |

### Extended Array Library

The Extended Array Library provides support for non-vector arrays. That is, arrays that have more than one dimension or arrays that have non-zero lower bounds. The Extended Array Library doesn't add any extra types, but it does extend the array-handling mechanism.

### Extended Numerics Library

| Name | Namespace | Base type | CIL type | Assembly name | Assembly version |
| Decimal | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| Double | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| Math | System | System.Object | class | mscorlib | 2.0.x.x |
| NotFiniteNumberException | System | System.ArithmeticException | class | mscorlib | 2.0.x.x |
| Single | System | System.ValueType | structure | mscorlib | 2.0.x.x |

### Parallel Library

| Name | Namespace | Base type | CIL type | Assembly name | Assembly version |
| ParallelEnvironment | System.Threading.Parallel | System.Object | class | mscorlib | 2.0.x.x |
| ParallelFor | System.Threading.Parallel | System.Threading.Parallel.ParallelLoop<int32> | class | System.Threading.Parallel | 2.0.x.x |
| ParallelForEach<T> | System.Threading.Parallel | System.Threading.Parallel.ParallelLoop<T> | class | System.Threading.Parallel | 2.0.x.x |
| ParallelLoop<T> | System.Threading.Parallel | System.Object | class | System.Threading.Parallel | 2.0.x.x |
| ParallelWhile<T> | System.Threading.Parallel | System.Threading.Parallel.ParallelLoop<T> | class | System.Threading.Parallel | 2.0.x.x |

### Vararg Library

| Name | Namespace | Base type | CIL type | Assembly name | Assembly version |
| ArgIterator | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| RuntimeArgumentHandle | System | System.ValueType | structure | mscorlib | 2.0.x.x |
| TypedReference | System | System.ValueType | structure | mscorlib | 2.0.x.x |