The multidimensional indexers is almost similar to multidimensional arrays. For the efficient content-based retrieval of data, multidimensional indexers are used. To create multi-dimensional indexer you have to pass at least two parameters in the argument list of indexer declaration. To access a single element of a multi-dimensional indexer, use integer subscripts. Each subscript indexes a dimension like the first indexes the row dimension, the second indexes the column dimension and so on.

Example 1: Using get and set accessor

// C# program to illustrate the 
// Multidimensional Indexers
using System;
    
class TAS {
      
    // reference to underlying 2D array
    int[, ] data = new int[5, 5];
      
      
    // declaring Multidimensional Indexer
    public int this[int index1, int index2]
    {
        // get accessor
        get 
        {
              
             // it returns the values which
            // read the indexes
            return data[index1, index2];
              
        }
          
        // set accessor
        set 
        {
              
            // write the values in 'data'
            // using value keyword
            data[index1, index2] = value;
              
        }
    }
}
  
// Driver Class
class Tech {
      
      
    // Main Method
    public static void Main(String []args)
    {
          
        // creating the instance of 
        // Class TAS as "index"
        TAS index = new TAS();
          
  
        // assign the values accordingly to
        // the indexes of the array
        // 1st row
        index[0, 0] = 1;
        index[0, 1] = 2;
        index[0, 2] = 3;
          
        // 2nd row
        index[1, 0] = 4;
        index[1, 1] = 5;
        index[1, 2] = 6;
          
        // 3rd row
        index[2, 0] = 7;
        index[2, 1] = 8;
        index[2, 2] = 9;
      
        // displaying the values
        Console.WriteLine("{0}\t{1}\t{2}\n{3}\t{4}\t{5}\n{6}\t{7}\t{8}",
                                  index[0, 0], index[0, 1], index[0, 2],
                                  index[1, 0], index[1, 1], index[1, 2], 
                                  index[2, 0], index[2, 1], index[2, 2]);
      
    }
}

Output:

1    2    3
4    5    6
7    8    9

Example 2: Without using the “set” accessor i.e only using Read-Only Property

// C# program to illustrate the Multidimensional 
// Indexer without using set accessor 
using System;
  
class TAS {
      
    // default constructor
    public TAS() {} 
  
    // Multidimensional Indexer
    public int this[int i1, int i2]
    {
          
        // get accessor
        get 
        {
              
            // read only properties
            return (i1 + i2);
        }
          
        // No set accessor used
    }
  
// Main Method
public static void Main(String []args)
{
      
    // creating object of class
    // "TAS" as "index"
    TAS index = new TAS();
      
    // displaying the values
    for (int i = 0; i <= 2; i++) {
          
        for (int j = 1; j <= 3; j++)
        {
            Console.Write(index[i, j] + "\t");
        }
          
        Console.WriteLine();
    }
}
}

Output:

1    2    3    
2    3    4    
3    4    5