Custom attribute classes in C Sharp (C#) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a custom attribute class named MyAttribute.

C Sharp (C#)

public class [1] : System.Attribute {}

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AMyAttribute

BCustomAttr

CAttributeClass

DMyClass

Attempts:

3 left

💡 Hint

Common Mistakes

Naming the class without 'Attribute' suffix.

Not inheriting from System.Attribute.

The custom attribute class must be named MyAttribute and inherit from System.Attribute.

2fill in blank

medium

Complete the code to apply the custom attribute MyAttribute to the class Sample.

C Sharp (C#)

[[1]]
public class Sample {}

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AMyClass

BAttribute

CCustomAttribute

DMyAttribute

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong attribute name.

Missing the square brackets.

To apply the attribute, use its class name without the 'Attribute' suffix if desired, but here the full name MyAttribute is used.

3fill in blank

hard

Fix the error in the attribute constructor to accept a string parameter named description.

C Sharp (C#)

public class MyAttribute : System.Attribute {
    public string Description { get; }
    public MyAttribute([1]) {
        Description = description;
    }
}

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Adouble description

Bint description

Cstring description

Dbool description

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong parameter type.

Mismatching parameter name and property.

The constructor must accept a string parameter named description to assign it to the property.

4fill in blank

hard

Fill both blanks to create a dictionary using ToDictionary that maps property names to their types for properties with type string.

C Sharp (C#)

var stringProps = typeof(MyAttribute).GetProperties()
    .Where(prop => prop.PropertyType == typeof(string))
    .ToDictionary(prop => [1], prop => [2]);

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Aprop.Name

Bprop.PropertyType

Cprop.GetValue(this)

Dprop.ToString()

Attempts:

3 left

💡 Hint

Common Mistakes

Using property values instead of names or types.

Using incorrect property methods.

The dictionary keys are property names (prop.Name) and values are their types (prop.PropertyType).

5fill in blank

hard

Fill all three blanks to create a method that returns the description from the MyAttribute applied to a class.

C Sharp (C#)

public static string GetDescription(Type t) {
    var attr = (MyAttribute)Attribute.GetCustomAttribute(t, typeof([1]));
    return attr == null ? [2] : attr.[3];
}

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AMyAttribute

Bstring.Empty

CDescription

DAttribute

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong attribute type in GetCustomAttribute.

Returning null instead of empty string.

Accessing wrong property name.

The method gets the MyAttribute from the type, returns empty string if none, else returns the Description property.