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Type.GetField Method

Definition

Gets a specific field of the current Type.

Overloads

GetField(String)

Searches for the public field with the specified name.

GetField(String, BindingFlags)

Searches for the specified field, using the specified binding constraints.

GetField(String)

Source:
Type.cs
Source:
Type.cs
Source:
Type.cs

Searches for the public field with the specified name.

public System.Reflection.FieldInfo? GetField (string name);
public System.Reflection.FieldInfo GetField (string name);

Parameters

name
String

The string containing the name of the data field to get.

Returns

An object representing the public field with the specified name, if found; otherwise, null.

Implements

Exceptions

name is null.

This Type object is a TypeBuilder whose CreateType() method has not yet been called.

Examples

The following example gets the Type object for the specified class, obtains the FieldInfo object for the field, and displays the value of the field.


using System;
using System.Reflection;

public class MyFieldClassA
{
    public string Field = "A Field";
}

public class MyFieldClassB
{
    private string field = "B Field";
    public string Field
    {
        get
        {
            return field;
        }
        set
        {
            if (field!=value)
            {
                field=value;
            }
        }
    }
}

public class MyFieldInfoClass
{
    public static void Main()
    {
        MyFieldClassB myFieldObjectB = new MyFieldClassB();
        MyFieldClassA myFieldObjectA = new MyFieldClassA();

        Type myTypeA = typeof(MyFieldClassA);
        FieldInfo myFieldInfo = myTypeA.GetField("Field");

        Type myTypeB = typeof(MyFieldClassB);
        FieldInfo myFieldInfo1 = myTypeB.GetField("field",
            BindingFlags.NonPublic | BindingFlags.Instance);

        Console.WriteLine("The value of the public field is: '{0}'",
            myFieldInfo.GetValue(myFieldObjectA));
        Console.WriteLine("The value of the private field is: '{0}'",
            myFieldInfo1.GetValue(myFieldObjectB));
    }
}

Remarks

The search for name is case-sensitive. The search includes public static and public instance fields.

If the current Type represents a constructed generic type, this method returns the FieldInfo 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 fields of the class constraint.

See also

Applies to

.NET 9 e outras versões
Produto Versões
.NET Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 2.0, 2.1

GetField(String, BindingFlags)

Source:
Type.cs
Source:
Type.cs
Source:
Type.cs

Searches for the specified field, using the specified binding constraints.

public abstract System.Reflection.FieldInfo? GetField (string name, System.Reflection.BindingFlags bindingAttr);
public abstract System.Reflection.FieldInfo GetField (string name, System.Reflection.BindingFlags bindingAttr);

Parameters

name
String

The string containing the name of the data field to get.

bindingAttr
BindingFlags

A bitwise combination of the enumeration values that specify how the search is conducted.

-or-

Default to return null.

Returns

An object representing the field that matches the specified requirements, if found; otherwise, null.

Implements

Exceptions

name is null.

Examples

The following example gets the Type object for the specified class, obtains the FieldInfo object for the field that matches the specified binding flags, and displays the value of the field.


using System;
using System.Reflection;

public class MyFieldClassA
{
    public string Field = "A Field";
}

public class MyFieldClassB
{
    private string field = "B Field";
    public string Field
    {
        get
        {
            return field;
        }
        set
        {
            if (field!=value)
            {
                field=value;
            }
        }
    }
}

public class MyFieldInfoClass
{
    public static void Main()
    {
        MyFieldClassB myFieldObjectB = new MyFieldClassB();
        MyFieldClassA myFieldObjectA = new MyFieldClassA();

        Type myTypeA = typeof(MyFieldClassA);
        FieldInfo myFieldInfo = myTypeA.GetField("Field");

        Type myTypeB = typeof(MyFieldClassB);
        FieldInfo myFieldInfo1 = myTypeB.GetField("field",
            BindingFlags.NonPublic | BindingFlags.Instance);

        Console.WriteLine("The value of the public field is: '{0}'",
            myFieldInfo.GetValue(myFieldObjectA));
        Console.WriteLine("The value of the private field is: '{0}'",
            myFieldInfo1.GetValue(myFieldObjectB));
    }
}

Remarks

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.
  1. 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.

  2. 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.

  3. Custom attributes are not part of the common type system.

The following BindingFlags filter flags can be used to define which fields 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 fields in the search.

  • Specify BindingFlags.NonPublic to include non-public fields (that is, private, internal, and protected fields) 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 fields declared on the Type, not fields that were simply inherited.

See System.Reflection.BindingFlags for more information.

If the current Type represents a constructed generic type, this method returns the FieldInfo 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 fields of the class constraint.

See also

Applies to

.NET 9 e outras versões
Produto Versões
.NET Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 2.0, 2.1