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How to Resolve Error "CS0548: property or indexer must have at least one accessor" in C#

The Compiler Error CS0548 is a syntax declaration error. The message reads: "'PropertyName' : property or indexer must have at least one accessor".

In C#, a Property is distinct from a Field.

  • A Field (public int x;) is a direct storage location.
  • A Property (public int X { get; set; }) is a pair of methods (accessors) that behave like a field.

When you declare a property using curly braces { }, the compiler expects you to define how to access that property. You must provide at least a get (read), a set (write), or an init (initialize) accessor. A property defined with empty braces is functionally useless because it cannot be read from or written to.

This guide explains how to correctly define properties and indexers.

Understanding Accessors​

Accessors are the gateways to your property:

  • get: Defines how to retrieve the value.
  • set: Defines how to assign a value.
  • init (C# 9+): Defines how to assign a value only during object initialization.

If you declare a property like public int Score { }, you have created a named entity that exposes no gateways. It creates a syntax error because it fulfills no purpose.

Scenario 1: The Empty Property Block​

This error usually happens when a developer forgets to type the get; set; shorthand (Auto-Implemented Properties) or intends to write the logic later and leaves the braces empty.

Example of error​

public class User
{
    // ⛔️ Error CS0548: 'User.Name' : property or indexer must have at least one accessor.
    // Curly braces indicate a property, but it is empty.
    public string Name { }
}

Solution: Add Accessors​

You must decide how this property behaves.

Option A: Auto-Implemented Property​

If you just want a simple storage slot (like a field), use the shorthand syntax.

public class User
{
    // ✅ Correct: The compiler generates the backing field automatically.
    public string Name { get; set; }
}

Option B: Computed Property​

If the property returns a calculated value (Read-Only).

public class User
{
    // ✅ Correct: Has a 'get' accessor.
    public string Name 
    { 
        get { return "Unknown"; } 
    }
    
    // Or expression-bodied syntax (which effectively creates a getter):
    // public string Name => "Unknown";
}

Option C: Use a Field​

If you didn't mean to create a property at all, remove the braces.

public class User
{
    // ✅ Correct: This is now a Field, not a Property.
    public string Name;
}

Scenario 2: The Empty Indexer Block​

Indexers allow you to access an object like an array (e.g., myObject[0]). Like properties, they require get or set accessors to function.

Example of error​

public class DataStore
{
    private string[] _data = new string[10];

    // ⛔️ Error CS0548: Indexer must have at least one accessor.
    public string this[int index]
    {
        // Missing logic here
    }
}

Solution: Implement Get/Set​

Define how the indexer interacts with your internal data.

public class DataStore
{
    private string[] _data = new string[10];

    // ✅ Correct: Defines read and write access
    public string this[int index]
    {
        get { return _data[index]; }
        set { _data[index] = value; }
    }
}

Conclusion​

CS0548 enforces the structure of properties.

  1. Check the Braces: If you see { }, you must put something inside.
  2. Add get; set;: This is the standard fix for storing data.
  3. Remove Braces: If you just wanted a simple variable, delete the braces to make it a Field.

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