Type.GetFields
Method
Definition
Overloads
| GetFields() |
Returns all the public fields of the current Type. |
| GetFields(BindingFlags) |
When overridden in a derived class, searches for the fields defined for the current Type, using the specified binding constraints. |
GetFields()
Returns all the public fields of the current Type.
public System.Reflection.FieldInfo[] GetFields ();
An array of FieldInfo objects representing all the public fields defined for the current Type.
-or-
An empty array of type FieldInfo, if no public fields are defined for the current Type.
Examples
The following example shows a use of the GetFields() method.
#using <system.dll>
using namespace System;
using namespace System::Reflection;
using namespace System::ComponentModel::Design;
int main()
{
try
{
// Get the type handle of a specified class.
Type^ myType = ViewTechnology::typeid;
// Get the fields of the specified class.
array<FieldInfo^>^myField = myType->GetFields();
Console::WriteLine( "\nDisplaying fields that have SpecialName attributes:\n" );
for ( int i = 0; i < myField->Length; i++ )
{
// Determine whether or not each field is a special name.
if ( myField[ i ]->IsSpecialName )
{
Console::WriteLine( "The field {0} has a SpecialName attribute.", myField[ i ]->Name );
}
}
}
catch ( Exception^ e )
{
Console::WriteLine( "Exception : {0} ", e->Message );
}
}
using System;
using System.Reflection;
using System.ComponentModel.Design;
class FieldInfo_IsSpecialName
{
public static void Main()
{
try
{
// Get the type handle of a specified class.
Type myType = typeof(ViewTechnology);
// Get the fields of the specified class.
FieldInfo[] myField = myType.GetFields();
Console.WriteLine("\nDisplaying fields that have SpecialName attributes:\n");
for(int i = 0; i < myField.Length; i++)
{
// Determine whether or not each field is a special name.
if(myField[i].IsSpecialName)
{
Console.WriteLine("The field {0} has a SpecialName attribute.",
myField[i].Name);
}
}
}
catch(Exception e)
{
Console.WriteLine("Exception : {0} " , e.Message);
}
}
}
Imports System
Imports System.Reflection
Imports System.ComponentModel.Design
Imports Microsoft.VisualBasic
Class FieldInfo_IsSpecialName
Public Shared Sub Main()
Try
' Get the type handle of a specified class.
Dim myType As Type = GetType(ViewTechnology)
' Get the fields of a specified class.
Dim myField As FieldInfo() = myType.GetFields()
Console.WriteLine(ControlChars.Cr + "Displaying fields that have SpecialName attributes:" + ControlChars.Cr)
Dim i As Integer
For i = 0 To myField.Length - 1
' Determine whether or not each field is a special name.
If myField(i).IsSpecialName Then
Console.WriteLine("The field {0} has a SpecialName attribute.", myField(i).Name)
End If
Next i
Catch e As Exception
Console.WriteLine("Exception : {0} ", e.Message.ToString())
End Try
End Sub 'Main
End Class 'FieldInfo_IsSpecialName
Remarks
The GetFields method does not return fields in a particular order, such as alphabetical or declaration order. Your code must not depend on the order in which fields are returned, because that order varies.
The following table shows what members of a base class are returned by the Get methods when reflecting on a type.
| Member Type | Static | Non-Static |
|---|---|---|
| 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. |
Hide-by-name-and-signature considers all of the parts of the signature, including custom modifiers, return types, parameter types, sentinels, and unmanaged calling conventions. This is a binary comparison.
For reflection, properties and events are hide-by-name-and-signature. If you have a property with both a get and a set accessor in the base class, but the derived class has only a get accessor, the derived class property hides the base class property, and you will not be able to access the setter on the base class.
Custom attributes are not part of the common type system.
If the current Type represents a constructed generic type, this method returns the FieldInfo objects with the type parameters replaced by the appropriate type arguments.
If the current Type represents a type parameter in the definition of a generic type or generic method, this method searches the public fields of the class constraint.
GetFields(BindingFlags)
When overridden in a derived class, searches for the fields defined for the current Type, using the specified binding constraints.
public abstract System.Reflection.FieldInfo[] GetFields (System.Reflection.BindingFlags bindingAttr);
- bindingAttr
- BindingFlags
A bitmask comprised of one or more BindingFlags that specify how the search is conducted.
-or-
Zero, to return null.
An array of FieldInfo objects representing all fields defined for the current Type that match the specified binding constraints.
-or-
An empty array of type FieldInfo, if no fields are defined for the current Type, or if none of the defined fields match the binding constraints.
Examples
The following example shows a use of the GetFields(BindingFlags) method.
using namespace System;
using namespace System::Reflection;
using namespace System::Runtime::InteropServices;
public ref class AttributesSample
{
public:
void Mymethod( int int1m, [Out]interior_ptr<String^> str2m, interior_ptr<String^> str3m )
{
*str2m = "in Mymethod";
}
};
void PrintAttributes( Type^ attribType, int iAttribValue )
{
if ( !attribType->IsEnum )
{
Console::WriteLine( "This type is not an enum." );
return;
}
array<FieldInfo^>^fields = attribType->GetFields( static_cast<BindingFlags>(BindingFlags::Public | BindingFlags::Static) );
for ( int i = 0; i < fields->Length; i++ )
{
int fieldvalue = safe_cast<Int32>(fields[ i ]->GetValue( nullptr ));
if ( (fieldvalue & iAttribValue) == fieldvalue )
{
Console::WriteLine( fields[ i ]->Name );
}
}
}
int main()
{
Console::WriteLine( "Reflection.MethodBase.Attributes Sample" );
// Get the type.
Type^ MyType = Type::GetType( "AttributesSample" );
// Get the method Mymethod on the type.
MethodBase^ Mymethodbase = MyType->GetMethod( "Mymethod" );
// Display the method name.
Console::WriteLine( "Mymethodbase = {0}", Mymethodbase );
// Get the MethodAttribute enumerated value.
MethodAttributes Myattributes = Mymethodbase->Attributes;
// Display the flags that are set.
PrintAttributes( System::Reflection::MethodAttributes::typeid, (int)Myattributes );
return 0;
}
using System;
using System.Reflection;
class AttributesSample
{
public void Mymethod (int int1m, out string str2m, ref string str3m)
{
str2m = "in Mymethod";
}
public static int Main(string[] args)
{
Console.WriteLine ("Reflection.MethodBase.Attributes Sample");
// Get the type.
Type MyType = Type.GetType("AttributesSample");
// Get the method Mymethod on the type.
MethodBase Mymethodbase = MyType.GetMethod("Mymethod");
// Display the method name.
Console.WriteLine("Mymethodbase = " + Mymethodbase);
// Get the MethodAttribute enumerated value.
MethodAttributes Myattributes = Mymethodbase.Attributes;
// Display the flags that are set.
PrintAttributes(typeof(System.Reflection.MethodAttributes), (int) Myattributes);
return 0;
}
public static void PrintAttributes(Type attribType, int iAttribValue)
{
if (!attribType.IsEnum)
{
Console.WriteLine("This type is not an enum.");
return;
}
FieldInfo[] fields = attribType.GetFields(BindingFlags.Public | BindingFlags.Static);
for (int i = 0; i < fields.Length; i++)
{
int fieldvalue = (Int32)fields[i].GetValue(null);
if ((fieldvalue & iAttribValue) == fieldvalue)
{
Console.WriteLine(fields[i].Name);
}
}
}
}
Imports System
Imports System.Reflection
Imports Microsoft.VisualBasic
Class AttributesSample
Public Sub Mymethod(ByVal int1m As Integer, ByRef str2m As String, ByRef str3m As String)
str2m = "in Mymethod"
End Sub 'Mymethod
Public Shared Function Main(ByVal args() As String) As Integer
Console.WriteLine("Reflection.MethodBase.Attributes Sample")
' Get the type.
Dim MyType As Type = Type.GetType("AttributesSample")
' Get the method Mymethod on the type.
Dim Mymethodbase As MethodBase = MyType.GetMethod("Mymethod")
' Display the method name.
Console.WriteLine("Mymethodbase = {0}.", Mymethodbase)
' Get the MethodAttribute enumerated value.
Dim Myattributes As MethodAttributes = Mymethodbase.Attributes
' Display the flags that are set.
PrintAttributes(GetType(System.Reflection.MethodAttributes), CInt(Myattributes))
Return 0
End Function 'Main
Public Shared Sub PrintAttributes(ByVal attribType As Type, ByVal iAttribValue As Integer)
If Not attribType.IsEnum Then
Console.WriteLine("This type is not an enum.")
Return
End If
Dim fields As FieldInfo() = attribType.GetFields((BindingFlags.Public Or BindingFlags.Static))
Dim i As Integer
For i = 0 To fields.Length - 1
Dim fieldvalue As Integer = CType(fields(i).GetValue(Nothing), Int32)
If (fieldvalue And iAttribValue) = fieldvalue Then
Console.WriteLine(fields(i).Name)
End If
Next i
End Sub 'PrintAttributes
End Class 'AttributesSample
Remarks
The GetFields method does not return fields in a particular order, such as alphabetical or declaration order. Your code must not depend on the order in which fields are returned, because that order varies.
The following BindingFlags filter flags can be used to define which fields to include in the search:
You must specify either
BindingFlags.InstanceorBindingFlags.Staticin order to get a return.Specify
BindingFlags.Publicto include public fields in the search.Specify
BindingFlags.NonPublicto include non-public fields (that is, private, internal, and protected fields) in the search. Only protected and internal fields on base classes are returned; private fields on base classes are not returned.Specify
BindingFlags.FlattenHierarchyto includepublicandprotectedstatic members up the hierarchy;privatestatic members in inherited classes are not included.
The following BindingFlags modifier flags can be used to change how the search works:
BindingFlags.DeclaredOnlyto search only the fields declared on the Type, not fields that were simply inherited.
See BindingFlags for more information.
If the current Type represents a constructed generic type, this method returns the FieldInfo objects with the type parameters replaced by the appropriate type arguments.
If the current Type represents a type parameter in the definition of a generic type or generic method, this method searches the public fields of the class constraint.