Use a String from a "try catch" in another "try catch"

Question

Hello,
how can I use a String inside a "try catch" outside in another "try catch"?
I need the string "server_token_string".

string server_token_string;

                try
                {
                    using (StreamReader sr = new StreamReader(@$"{localappdata}\Liquid Aqua\API\server_token.txt", Encoding.Default))
                    {
                        StringBuilder server_tokens = new StringBuilder();

                        // schreibt Zeile für Zeile auf den StringBuilder bis das Ende der Datei erreicht ist
                        while (!sr.EndOfStream)
                            server_tokens.AppendLine(sr.ReadLine()); fortschritt_label.Content = "Reading Server File..."; progress_bar.Value = 6;
                        server_token_string = server_tokens.ToString();
                    }
                }
                catch
                {

                }


                //Überprüfung Token
                try
                {
                    if (server_token_string.Contains(token_eingabe))

Answer 1

As long as the string is declared outside of the try/catch blocks and you initialize the string, then all should be fine:

string server_token_string = null;

try
{
    ...
    server_token_string = "ackbar";
}
catch
{
    ...
}

try
{
    ...
    if (server_token_string != null && server_token_string.Contains("ack"))
    {
    }
}
catch
{
    ...
}

Answer 2

When we use class members (property and field), we don't need to assign initial values to them, it will be done automatically. But local variables are different from class members, you must manually assign values to them.

I think this may have misled you.

When an exception occurs in the first try block, the code may not reach the 12th line of the displayed code, which will cause the server_token_string to be in an uninitialized state, so it cannot be used in the second try block.

Take a look at the explanation in this link to understand why it is designed this way:
Are C# uninitialized variables dangerous?

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