Gets the Type with the specified name, specifying whether to perform a case-sensitive search and whether to throw an exception if the type is not found.
- typeName
- The assembly-qualified name of the type to get. See Type.AssemblyQualifiedName. If the type is in the currently executing assembly or in Mscorlib.dll, it is sufficient to supply the type name qualified by its namespace.
- throwOnError
- true to throw an exception if the type cannot be found; false to return null.Specifying false also suppresses some other exception conditions, but not all of them. See the Exceptions section.
- ignoreCase
- true to perform a case-insensitive search for typeName, false to perform a case-sensitive search for typeName.
The type with the specified name. If the type is not found, the throwOnError parameter specifies whether null is returned or an exception is thrown. In some cases, an exception is thrown regardless of the value of throwOnError. See the Exceptions section.
Type Reason ArgumentNullException typeName is null. System.Reflection.TargetInvocationException A type initializer was invoked and threw an exception. TypeLoadException throwOnError is true and an error was encountered while loading the selected Type.
You can use the Type.GetType method to obtain a Type object for a type in another assembly, if the you know its namespace-qualified name. Type.GetType causes loading of the assembly specified in typeName. You can also load an assembly using the System.Reflection.Assembly.Load(System.Reflection.AssemblyName) method, and then use the Type.GetType or System.Reflection.Assembly.GetTypes methods of the System.Reflection.Assembly class to get Type objects. If a type is in an assembly known to your program at compile time, it is more efficient to use typeof in C#, Type.GetType in Visual Basic, or typeid in C++.
GetType only works on assemblies loaded from disk. If you call GetType to look up a type defined in a dynamic assembly defined using the System.Reflection.Emit services, you might get inconsistent behavior. The behavior depends on whether the dynamic assembly is persistent, that is, created using the RunAndSave or Save access modes of the System.Reflection.Emit.AssemblyBuilderAccess enumeration. If the dynamic assembly is persistent and has been written to disk before GetType is called, the loader finds the saved assembly on disk, loads that assembly, and retrieves the type from that assembly. If the assembly has not been saved to disk when GetType is called, the method returns null. GetType does not understand transient dynamic assemblies; therefore, calling GetType to retrieve a type in a transient dynamic assembly returns null.
To use GetType on a dynamic module, subscribe to the AppDomain.AssemblyResolve event and call GetType before saving. Otherwise, you will get two copies of the assembly in memory.
The throwOnError parameter specifies what happens when the type is not found, and also suppresses certain other exception conditions, as described in the Exceptions section. Some exceptions are thrown regardless of the value of throwOnError. For example, if the type is found but cannot be loaded, a TypeLoadException is thrown even if throwOnError is false.
The following table shows what members of a base class are returned by the Get methods when reflecting on a type.
Constructor |
No |
No |
Field |
No |
Yes. A field is always hide-by-name-and-signature. |
Event |
Not applicable |
The common type system rule is that the inheritance is the same as that of the methods that implement the property. Reflection treats properties as hide-by-name-and-signature. See note 2 below. |
Method |
No |
Yes. A method (both virtual and non-virtual) can be hide-by-name or hide-by-name-and-signature. |
Nested Type |
No |
No |
Property |
Not applicable |
The common type system rule is that the inheritance is the same as that of the methods that implement the property. Reflection treats properties as hide-by-name-and-signature. See note 2 below. |
Arrays or COM types are not searched for unless they have already been loaded into the table of available classes.
typeName can be the type name qualified by its namespace or an assembly-qualified name that includes an assembly name specification. See Type.AssemblyQualifiedName.
If typeName includes the namespace but not the assembly name, this method searches only the calling object's assembly and Mscorlib.dll, in that order. If typeName is fully qualified with the partial or complete assembly name, this method searches in the specified assembly. If the assembly has a strong name, a complete assembly name is required.
The Type.AssemblyQualifiedName property returns a fully qualified type name including nested types, the assembly name, and type arguments. All compilers that support the common language runtime will emit the simple name of a nested class, and reflection constructs a mangled name when queried, in accordance with the following conventions.
In the .NET Framework version 2.0, processor architecture is added to assembly identity, and can be specified as part of assembly name strings. For example, "ProcessorArchitecture=msil". However, it is not included in the string returned by the Type.AssemblyQualifiedName property, for compatibility reasons. You can also load types by creating an System.Reflection.AssemblyName object and passing it to an appropriate overload of the erload:System.Reflection.Assembly.Load method. You can then use the System.Reflection.Assembly.GetType(string) method to load types from the assembly. See also System.Reflection.AssemblyName.ProcessorArchitecture.
Backslash (\) |
Escape character. |
Backtick (`) |
Precedes one or more digits representing the number of type parameters, located at the end of the name of a generic type. |
Brackets ([]) |
Enclose a generic type argument list, for a constructed generic type; within a type argument list, enclose an assembly-qualified type. |
Comma (,) |
Precedes the Assembly name. |
Period (.) |
Denotes namespace identifiers. |
Plus sign (+) |
Precedes a nested class. |
For example, the fully qualified name for a class might look like this:
Example
TopNamespace.SubNameSpace.ContainingClass+NestedClass,MyAssembly
If the namespace were TopNamespace.Sub+Namespace, then the string would have to precede the plus sign (+) with an escape character (\) to prevent it from being interpreted as a nesting separator. Reflection emits this string as follows:
Example
TopNamespace.Sub\+Namespace.ContainingClass+NestedClass,MyAssembly
A "++" becomes "\+\+", and a "\" becomes "\\".
This qualified name can be persisted and later used to load the Type. To search for and load a Type, use Type.GetType either with the type name only or with the assembly qualified type name. Type.GetType with the type name only will look for the Type in the caller's assembly and then in the System assembly. Type.GetType with the assembly qualified type name will look for the Type in any assembly.
Type names may include trailing characters that denote additional information about the type, such as whether the type is a reference type, a pointer type or an array type. To retrieve the type name without these trailing characters, use t.GetElementType().ToString(), where t is the type.
Spaces are relevant in all type name components except the assembly name. In the assembly name, spaces before the ',' separator are relevant, but spaces after the ',' separator are ignored.
The name of a generic type ends with a backtick (`) followed by digits representing the number of generic type arguments. The purpose of this name mangling is to allow compilers to support generic types with the same name but with different numbers of type parameters, occurring in the same scope. For example, reflection returns the mangled names Tuple`1 and Tuple`2 from the generic methods Tuple(Of T) and Tuple(Of T0, T1) in Visual Basic, or Tuple<T> and Tuple<T0, T1> in Visual C#.
For generic types, the type argument list is enclosed in brackets, and the type arguments are separated by commas. For example, a generic Dictionary`2 has two type parameters. A Dictionary`2 of MyType with keys of type string might be represented as follows:
Example
System.Collections.Generic.Dictionary`2[System.String,MyType]
To specify an assembly-qualified type within a type argument list, enclose the assembly-qualified type within brackets. Otherwise, the commas that separate the parts of the assembly-qualified name are interpreted as delimiting additional type arguments. For example, a Dictionary`2 of MyType from MyAssembly.dll, with keys of type string, might be specified as follows:
Example
Type.GetType("System.Collections.Generic.Dictionary`2[System.String,[MyType,MyAssembly]]")
An assembly-qualified type can be enclosed in brackets only when it appears within a type parameter list. The rules for searching assemblies for qualified and unqualified types in type parameter lists are the same as the rules for qualified and unqualified nongeneric types.
Nullable types are a special case of generic types. For example, a nullable int is represented by the string "System.Nullable`1[System.Int32]".
In C#, C++, and Visual Basic you can also get nullable types using type operators. For example, the nullable bool type is returned by typeof(Nullable<bool>) in C#, by Nullable<Boolean>::typeid in C++, and by GetType(Nullable(Of Boolean)) in Visual Basic.
The following table shows the syntax you use with GetType for various types.
A nullable int |
Type.GetType("System.Nullable`1[System.Int32]") |
An unmanaged pointer to MyType |
Type.GetType("MyType*") |
An unmanaged pointer to a pointer to MyType |
Type.GetType("MyType**") |
A managed pointer or reference to MyType |
Type.GetType("MyType&"). Note that unlike pointers, references are limited to one level. |
A parent class and a nested class |
Type.GetType("MyParentClass+MyNestedClass") |
A one-dimensional array with a lower bound of 0 |
Type.GetType("MyArray[]") |
A one-dimensional array with an unknown lower bound |
Type.GetType("MyArray[*]") |
An n-dimensional array |
A comma (,) inside the brackets a total of n-1 times. For example, System.Object[,,] represents a three-dimensional Object array. |
A two-dimensional array's array |
Type.GetType("MyArray[][]") |
A rectangular two-dimensional array with unknown lower bounds |
Type.GetType("MyArray[,]") |
A generic type with one type argument |
Type.GetType("MyGenericType`1[MyType]") |
A generic type with two type arguments |
Type.GetType("MyGenericType`2[MyType,AnotherType]") |
A generic type with two assembly-qualified type arguments |
Type.GetType("MyGenericType`2[[MyType,MyAssembly],[AnotherType,AnotherAssembly]]") |
An assembly-qualified generic type with an assembly-qualified type argument |
Type.GetType("MyGenericType`1[[MyType,MyAssembly]],MyGenericTypeAssembly") |
A generic type whose type argument is a generic type with two type arguments |
Type.GetType("MyGenericType`1[AnotherGenericType`2[MyType,AnotherType]]") |
Type | Reason |
---|---|
System.Security.Permissions.ReflectionPermission | Requires permission to retrieve information on non-public members of types in loaded assemblies. See System.Security.Permissions.ReflectionPermissionFlag.TypeInformation. |