Get a specific field of the current type C#

To get a specific field of the current type in C#, you use the GetField() method from the System.Reflection namespace. This method returns a FieldInfo object that represents the field with the specified name, or null if the field is not found.

Syntax

Following is the syntax for getting a specific field using reflection −

Type type = typeof(ClassName);
FieldInfo fieldInfo = type.GetField("fieldName");

The GetField() method has several overloads that accept binding flags to control the search behavior −

FieldInfo fieldInfo = type.GetField("fieldName", BindingFlags.Public | BindingFlags.Instance);

Parameters

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

• bindingAttr (optional) − A bitmask comprised of one or more BindingFlags that specify how the search is conducted.

Return Value

Returns a FieldInfo object representing the field that matches the specified requirements, or null if the field is not found.

Getting a Public Field

This example demonstrates retrieving a public field from a class −

using System;
using System.Reflection;

public class Demo {
    public static void Main() {
        Type type = typeof(Subject);
        try {
            FieldInfo fieldInfo = type.GetField("SubName");
            Console.WriteLine("FieldInfo = {0}", fieldInfo);
            Console.WriteLine("Field Type = {0}", fieldInfo.FieldType);
            Console.WriteLine("Field Name = {0}", fieldInfo.Name);
        }
        catch (ArgumentNullException e) {
            Console.Write("{0}", e.GetType(), e.Message);
        }
    }
}

public class Subject {
    public string SubName = "Science";
}

The output of the above code is −

FieldInfo = System.String SubName
Field Type = System.String
Field Name = SubName

Getting Field Value

You can also retrieve the actual value of a field from an object instance −

using System;
using System.Reflection;

public class Demo {
    public static void Main() {
        Subject subject = new Subject();
        Type type = typeof(Subject);
        
        FieldInfo fieldInfo = type.GetField("SubName");
        if (fieldInfo != null) {
            object fieldValue = fieldInfo.GetValue(subject);
            Console.WriteLine("Field Value = {0}", fieldValue);
            
            // Set a new value
            fieldInfo.SetValue(subject, "Mathematics");
            Console.WriteLine("New Field Value = {0}", subject.SubName);
        }
    }
}

public class Subject {
    public string SubName = "Science";
}

The output of the above code is −

Field Value = Science
New Field Value = Mathematics

Handling ArgumentNullException

When you pass null as the field name, an ArgumentNullException is thrown −

using System;
using System.Reflection;

public class Demo {
    public static void Main() {
        Type type = typeof(Subject);
        try {
            FieldInfo fieldInfo = type.GetField(null);
            Console.WriteLine("FieldInfo = {0}", fieldInfo);
        }
        catch (ArgumentNullException e) {
            Console.WriteLine("Exception: {0}", e.GetType().Name);
            Console.WriteLine("Message: {0}", e.Message);
        }
    }
}

public class Subject {
    public string SubName = "Science";
}

The output of the above code is −

Exception: ArgumentNullException
Message: Value cannot be null.
Parameter name: name

Common Use Cases

• Dynamic field access − When field names are determined at runtime.

• Serialization/Deserialization − Reading and writing object data to different formats.

• Property mapping − Copying values between objects with similar structures.

• Debugging and testing − Inspecting object state during development.

Conclusion

The GetField() method in C# reflection provides a powerful way to access field information at runtime. It returns a FieldInfo object that can be used to read field metadata, get values, and set values dynamically, making it essential for scenarios requiring runtime type inspection.