Error concatenating string from path

Question

In this program right at the beginning has a function that creates a folder in the user’s documents to save some information

Giving a research I came to the conclusion that it should stay like this:

    static int PrepararTerreno()
    {
        string Diretorio = ("C://Users//{0}//Documents//Cadastro",Environment.UserName);
        Directory.CreateDirectory (Diretorio);
        return 0;
    }

It is for the program to see the user name and insert there in the middle of the string for the folder to be created in the documents of the user who opened the program.

But when I run the program the Visual studio gives this error:

CS0029 Cannot implicitly convert type "(string, string Username)" to "string"

Answer 1

This job is a little weird. If you are practicing then it would be interesting to practice what is most important and at the same time easier because it is not even programming itself. If you make a mistake that’s how you always do it.

The function name is not good because it doesn’t say what it really does. Unless she does something that is not yet in the code, but in this case a comment would be good, comments serve precisely for this.

The same goes for the return, if it will return something that is fixed, then it is better to return nothing, unless you will do other things later, and again a comment would be fine.

It makes no sense to use // in the text, or uses \\ or uses /. To \\ is necessary because the bar alone is an escape character since the backslash is used for formatting. Using the backslash can use the @ so you don’t have to duplicate it.

Can use interpolation there and avoid further headaches.

The mistake is that it is creating a tuple (example, another, one more, the last) composed of an object string and other object string with a name. And declared a variable of type string only (which is obviously not a tuple, is incompatible).

The statement is correct, the assignment is wrong. The parentheses left there make all the difference by creating a different kind, so I always talk:

Even the space in the function name is unnecessary, does not give an error, but gives a wrong indication, it looks like you are grouping expressions or creating a tuple instead of using a function. It sounds silly but the code is less readable. Even if it works not everything is right, get used to doing right and not just working. The worst mistakes are the ones the compiler doesn’t complain about.

And the variable isn’t even necessary.

Would be better off:

static void PrepararTerreno() => Directory.CreateDirectory($"C:/Users/{Environment.UserName}/Documents/Cadastro");

Or

static void PrepararTerreno() => Directory.CreateDirectory($@"C:\Users\{Environment.UserName}\Documents\Cadastro");

Or else

static void PrepararTerreno() => Directory.CreateDirectory($"C:\\Users\\{Environment.UserName}\\Documents\\Cadastro");

I put in the Github for future reference.

Answer 2

About Error CS0029:

The compiler requires an explicit conversion. For example, it may be need to convert a value r to the same type as a value l. Or, you must provide conversion routines to support certain operator burden.

You need to tell the compiler that you want that output in a specific way, in this case in the string format.

You could do as @Augusto Vasques quoted in the comment using the string.Format:

string diretorio = string.Format("C://Users//{0}//Documents//Cadastro", Environment.UserName);

or using the string.Concat:

string diretorio = string.Concat("C://Users//", Environment.UserName, "//Documents//Cadastro");

There are several ways to build a string, so if you want more definitions about concatenação de string you can have a quick summary on What is the most appropriate way to concatenate strings? here in the forum or consult official documentation.