Type.GetProperty Method (String, BindingFlags)
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Searches for the specified property, using the specified binding constraints.
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Function GetProperty ( _
name As String, _
bindingAttr As BindingFlags _
) As PropertyInfo
public PropertyInfo GetProperty(
string name,
BindingFlags bindingAttr
)
Parameters
- name
Type: System.String
The String containing the name of the property to get.
- bindingAttr
Type: System.Reflection.BindingFlags
A bitmask comprised of one or more BindingFlags that specify how the search is conducted.
-or-
Zero, to return nulla null reference (Nothing in Visual Basic).
Return Value
Type: System.Reflection.PropertyInfo
A PropertyInfo object representing the property that matches the specified requirements, if found; otherwise, nulla null reference (Nothing in Visual Basic).
Implements
Exceptions
| Exception | Condition |
|---|---|
| AmbiguousMatchException | More than one property is found with the specified name and matching the specified binding constraints. See Remarks. |
| ArgumentNullException | name is nulla null reference (Nothing in Visual Basic). |
Remarks
A property is considered public to reflection if it has at least one accessor that is public. Otherwise the property is considered private, and you must use BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static (in Visual Basic, combine the values using Or) to get it.
The following BindingFlags filter flags can be used to define which properties to include in the search:
You must specify either BindingFlags.Instance or BindingFlags.Static in order to get a return.
Specify BindingFlags.Public to include public properties in the search.
Specify BindingFlags.NonPublic to include non-public properties (that is, private and protected properties) in the search.
Specify BindingFlags.FlattenHierarchy to include public and protected static members up the hierarchy; private static members in inherited classes are not included.
The following BindingFlags modifier flags can be used to change how the search works:
BindingFlags.IgnoreCase to ignore the case of name.
BindingFlags.DeclaredOnly to search only the properties declared on the Type, not properties that were simply inherited.
See System.Reflection.BindingFlags for more information.
If the current Type represents a constructed generic type, this method returns the PropertyInfo 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 properties of the class constraint.
Situations in which AmbiguousMatchException occurs include the following:
A type contains two indexed properties that have the same name but different numbers of parameters. To resolve the ambiguity, use an overload of the GetProperty method that specifies parameter types.
A derived type declares a property that hides an inherited property with the same name, using the new modifier (Shadows in Visual Basic). To resolve the ambiguity, include BindingFlags.DeclaredOnly to restrict the search to members that are not inherited.
Indexers and Default Properties
Visual Basic 2005, Visual C# 2005, and Visual C++ 2005 have simplified syntax for accessing indexed properties and allow one indexed property to be a default for its type. For example, if the variable myList refers to a List<T>, the syntax myList[3] (myList(3) in Visual Basic) retrieves the element with the index of 3. You can overload the property.
In C#, this feature is called an indexer and cannot be refered to by name. By default, a C# indexer appears in metadata as an indexed property named "Item". However, a class library developer can use the IndexerNameAttribute attribute to change the name of the indexer in the metadata. For example, the String class has an indexer named Chars. Indexed properties created using languages other than C# can have names other than Item, as well.
To determine whether a type has a default property, use the GetCustomAttributes(Type, Boolean) method to test for the DefaultMemberAttribute attribute. If the type has DefaultMemberAttribute, the MemberName property returns the name of the default property.
Examples
The following example retrieves the type of a user-defined class, retrieves a property of that class and displays the property name in accordance with the specified binding constraints.
.gif "Note") Note: |
|---|
To run this example, see Building Examples That Use a Demo Method and a TextBlock Control. |
Imports System.Reflection
Public Class Example
Private myPropertyValue As Integer
' Declare MyProperty.
Public Property MyProperty() As Integer
Get
Return myPropertyValue
End Get
Set(ByVal Value As Integer)
myPropertyValue = Value
End Set
End Property
Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
Try
' Get a Type object corresponding to class Example.
Dim myType As Type = GetType(Example)
' Get a PropertyInfo object by passing property name and specifying BindingFlags.
Dim myPropInfo As PropertyInfo = _
myType.GetProperty("MyProperty", BindingFlags.Public Or BindingFlags.Instance)
' Display the Name property.
outputBlock.Text &= _
String.Format("{0} is a property of Example." & vbLf, _
myPropInfo.Name)
Catch e As NullReferenceException
outputBlock.Text &= _
String.Format("MyProperty does not exist in Example." & vbLf, _
e.Message)
End Try
End Sub
End Class
using System;
using System.Reflection;
class MyClass
{
private int myProperty;
// Declare MyProperty.
public int MyProperty
{
get
{
return myProperty;
}
set
{
myProperty = value;
}
}
}
public class Example
{
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
try
{
// Get Type object of MyClass.
Type myType = typeof(MyClass);
// Get the PropertyInfo by passing the property name and specifying the BindingFlags.
PropertyInfo myPropInfo = myType.GetProperty("MyProperty", BindingFlags.Public | BindingFlags.Instance);
// Display Name propety to console.
outputBlock.Text += String.Format("{0} is a property of MyClass.", myPropInfo.Name) + "\n";
}
catch (NullReferenceException e)
{
outputBlock.Text += "MyProperty does not exist in MyClass." + e.Message + "\n";
}
}
}
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.