StringBuilder Equals

Two StringBuilder instances may have the same string contents. We test them for equality. The Equals instance method is ideal for this.

Method notes

Equals() doesn't copy any characters or cause excessive method calls. But it will check the capacities of the StringBuilders.

Example code

The example shows an Equals test that succeeds. The 2 StringBuilder objects in the example both contain the same chars and have the same capacity.

using System;
using System.Text;

// Create two StringBuilders with the same contents.
StringBuilder builder1 = new StringBuilder();
builder1.Append("One ");
builder1.Append("two");

StringBuilder builder2 = new StringBuilder();
builder2.Append("One ");
builder2.Append("two");

// See if the StringBuilder contents are equal.
if (builder1.Equals(builder2))
{
    Console.WriteLine("Equal");
}
Equal

Implementation

Equals returns true when 3 conditions are true. Two objects must have the same capacity, the same MaxCapacity, and the same characters in their buffers.

Contents

Sometimes you may need to test 2 StringBuilders that may have different capacities but the same contents. To do this, iterate through their characters with the indexer.

A summary

We used the Equals instance method on StringBuilder. This method is overridden and provides a powerful and efficient way to test two StringBuilders for equality.