StringBuilder does not contain a definition for Append

Question

StringBuilder does not contain a definition for Append

Seph 6

I'm having some error and I'm too much of a noob to figure out how to get around it. It's saying

Error CS1061 'StringBuilder' does not contain a definition for 'Append' and no accessible extension method 'Append' accepting a first argument of type 'StringBuilder' could be found (are you missing a using directive or an assembly reference?)

using System;

namespace Working_with_Strings  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
  
StringBuilder myString = new StringBuilder();  
  
            for (int i = 0; i < 100; i++)  
            {  
                myString.Append("--");  
            }  

            Console.WriteLine(myString);  
            Console.ReadLine();  
       }   
 }

}

It seems that anything I do regarding StringBuilder doesn't work. Even opening a new project and copy/pasting it directly from https://learn.microsoft.com/en-us/dotnet/standard/base-types/stringbuilder it just doesn't work.

4 answers

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Answer 1

Seph 6

No I didn't do anything outside of just try to use stringbuilder. It works normally in the video I am following, but when I do it it just throws out a bunch of errors and doesn't seem to exist for me.

When I click on it it brings me to Internal Class StringBuilder, which has nothing.

namespace Working_with_Strings
{
    internal class StringBuilder
    {
    }
}

AgaveJoe 30,126 Reputation points

2021-08-04T19:49:37.107+00:00
Delete the namespace and class. Most likely you did not add...

using System.Text;

... at the top of the file where you are using the StringBuilder. Visual Studio prompted you to fix the StringBuilder reference and you selected create a class rather than add a reference.
Seph 6 Reputation points

2021-08-04T19:57:06.223+00:00

Thank you, that fixed it.

Why the hell would it do that? So confusing! I never would have figured that out.
Sam of Simple Samples 5,546 Reputation points

2021-08-04T20:09:29.223+00:00

It does not know what you need to do. We assume it offered you the opportunity to add the Using directive but you chose to create the class instead. So you have learned from this. Now you know not to add a class when the class should already exist and you have learned that you often need to add a Using directive.

Answer 2

Sam of Simple Samples 5,546

Are you missing a using directive or an assembly reference?

Do you have the following at the beginning of your program (file)?

using System.Text;

If not then add that.

Seph 6 Reputation points

2021-08-04T19:43:45.657+00:00

When I add using System.Text it just turns into gray text and tells me that using directive is unnecessary. It doesn't change the append not being a thing.

Answer 3

Timon Yang-MSFT 9,606

Did you define a class called StringBuilder yourself?

Hold down the Ctrl key and click on the class to see where the program will jump to?

Or hover your mouse over this class to see if it is a System.Text.StringBuilder like the picture below:

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Answer 4

Karen Payne MVP 35,586 Volunteer Moderator

What happens with using

System.Text.StringBuilder builder = new StringBuilder();
builder.Append("Hello");

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StringBuilder does not contain a definition for Append

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