Creating a Case-Sensitive HybridDictionary with specified initial size in C#

The HybridDictionary class in C# is a collection that combines the benefits of both ListDictionary and Hashtable. It automatically switches from a ListDictionary (for small collections) to a Hashtable (for larger collections) based on the number of elements. You can create a case-sensitive HybridDictionary with a specified initial size using its constructor.

Syntax

Following is the syntax for creating a HybridDictionary with specified initial size and case sensitivity −

HybridDictionary myDict = new HybridDictionary(initialSize, caseInsensitive);

Parameters

• initialSize − The approximate number of entries that the HybridDictionary can initially contain.

• caseInsensitive − A boolean value that specifies whether the HybridDictionary is case-insensitive. Set to false for case-sensitive, true for case-insensitive.

Creating a Case-Sensitive HybridDictionary

To create a case-sensitive HybridDictionary, set the second parameter to false. This allows keys like "A" and "a" to be treated as different keys −

Example

using System;
using System.Collections;
using System.Collections.Specialized;

public class Demo {
    public static void Main() {
        HybridDictionary myDict = new HybridDictionary(5, false);
        myDict.Add("A", "AB");
        myDict.Add("B", "BC");
        myDict.Add("C", "DE");
        myDict.Add("D", "FG");
        myDict.Add("e", "fg");
        
        Console.WriteLine("Key/Value pairs...");
        foreach(DictionaryEntry de in myDict)
            Console.WriteLine("Key = " + de.Key + ", Value = " + de.Value);
    }
}

The output of the above code is −

Key/Value pairs...
Key = A, Value = AB
Key = B, Value = BC
Key = C, DE
Key = D, Value = FG
Key = e, Value = fg

Case-Insensitive vs Case-Sensitive Comparison

The following example demonstrates the difference between case-insensitive (true) and case-sensitive (false) HybridDictionary behavior −

Example

using System;
using System.Collections;
using System.Collections.Specialized;

public class Demo {
    public static void Main() {
        Console.WriteLine("Case-Sensitive HybridDictionary:");
        HybridDictionary caseSensitive = new HybridDictionary(5, false);
        caseSensitive.Add("A", "Value1");
        caseSensitive.Add("a", "Value2");
        
        foreach(DictionaryEntry de in caseSensitive)
            Console.WriteLine("Key = " + de.Key + ", Value = " + de.Value);
        
        Console.WriteLine("\nCase-Insensitive HybridDictionary:");
        HybridDictionary caseInsensitive = new HybridDictionary(5, true);
        caseInsensitive.Add("B", "Value3");
        Console.WriteLine("Added key 'B' with value 'Value3'");
        
        try {
            caseInsensitive.Add("b", "Value4");
        }
        catch (ArgumentException ex) {
            Console.WriteLine("Error: " + ex.Message);
        }
    }
}

The output of the above code is −

Case-Sensitive HybridDictionary:
Key = A, Value = Value1
Key = a, Value = Value2

Case-Insensitive HybridDictionary:
Added key 'B' with value 'Value3'
Error: An item with the same key has already been added.

How It Works

The HybridDictionary automatically chooses the underlying data structure based on performance:

• For collections with 10 or fewer items, it uses a ListDictionary (linked list implementation).

• For collections with more than 10 items, it switches to a Hashtable for better performance.

• The initialSize parameter helps determine which implementation to start with.

Conclusion

The HybridDictionary with case sensitivity provides flexibility in key handling while optimizing performance for different collection sizes. Setting the case-sensitive parameter to false allows distinct keys that differ only in case, making it useful for scenarios where case matters in your key comparisons.