How can we prepend strings with StringBuilder?

Question

I know we can append strings using StringBuilder. Is there a way we can prepend strings (i.e. add strings in front of a string) using StringBuilder

Answer 1

Here's what you can do If you want to prepend using Java's StringBuilder class:

StringBuilder str = new StringBuilder();
str.Insert(0, "text");

Answer 2

You could try an extension method:

/// <summary>
/// kind of a dopey little one-off for StringBuffer, but 
/// an example where you can get crazy with extension methods
/// </summary>
public static void Prepend(this StringBuilder sb, string s)
{
    sb.Insert(0, s);
}

StringBuilder sb = new StringBuilder("World!");
sb.Prepend("Hello "); // Hello World!

Answer 3

Try using Insert()

StringBuilder MyStringBuilder = new StringBuilder("World!");
MyStringBuilder.Insert(0,"Hello "); // Hello World!

Answer 4

If I understand you correctly, the insert method looks like it'll do what you want. Just insert the string at offset 0.

Answer 5

You could create an extension for StringBuilder yourself with a simple class:

namespace Application.Code.Helpers
{
    public static class StringBuilderExtensions
    {
        #region Methods

        public static void Prepend(this StringBuilder sb, string value)
        {
            sb.Insert(0, value);
        }

        public static void PrependLine(this StringBuilder sb, string value)
        {
            sb.Insert(0, value + Environment.NewLine);
        }

        #endregion
    }
}

Then, just add:

using Application.Code.Helpers;

To the top of any class that you want to use the StringBuilder in and any time you use intelli-sense with a StringBuilder variable, the Prepend and PrependLine methods will show up. Just remember that when you use Prepend, you will need to Prepend in reverse order than if you were Appending.

Answer 6

This should work:

aStringBuilder = "newText" + aStringBuilder;