C# - Process.Start - using global variable as password - "cannot convert from 'string' to 'System.Security.SecureString'

Question

I designed a login form and wanted the username and password entered to be stored as variables I could call in other forms (overall program is a collection of .exe files and powershell scripts that I want to run as the username and password initially entered in my login form).

At the start of the program I created "global variables" using this code:

class usernameGlobalVariable
    {
        public static string var = "";
    }
    class passwordGlobalVariable
    {
        public static string var = "";
    }

In the login form I stored the username and password entered into these global variables this way:

private void usernameTextBox_TextChanged(object sender, EventArgs e)
    {
        usernameGlobalVariable.var = usernameTextBox.Text;
    }


    private void passwordTextBox_TextChanged(object sender, EventArgs e)
    {
        passwordGlobalVariable.var = passwordTextBox.Text;
    }

When I want to start a process I call it using this code (to run it as the username and password stored by the login form):

string fileName = "c:\\hdatools\\Ping2.exe";
string arguments = "";
string domain = "vantage";
private void Button2_Click(object sender, EventArgs e)
    {

    Process.Start(
    fileName,
    arguments,
    usernameGlobalVariable.var,
    passwordGlobalVariable.var,
    domain);

    }

The main error I get is on the line passwordGlobalVariable.var, The error says

Argument 4: cannot convert from 'string' to 'System.Security.SecureString'

I've tried different ways to try to convert `passwordGlobalVariable.var' to a secure string, or to give another string variable its contents and then render that variable as a secure string. I've finally run out of ideas. Thanks in advance for the help.

Why do you use a reserved keyword to name a variable? This is very confusing and misleading. An example to not follow. — Steve
– Steve, Commented Jun 18, 2014 at 21:07

Yair Nevet · Accepted Answer · 2014-06-19 16:08:44Z

3

Argument 4: cannot convert from 'string' to 'System.Security.SecureString'

because var is a string and not a SecureString, look:

class passwordGlobalVariable
{
   public static string var = "";
}

So change it to:

class passwordGlobalVariable
{
   public static SecureString var;
}

And later on, change your passwordTextBox_TextChanged event-handler to convert your password string into a SecureString:

private void passwordTextBox_TextChanged(object sender, EventArgs e)
{
   SecureString passWord = new SecureString();
   foreach (char c in passwordTextBox.Text.ToCharArray())
   {
     passWord.AppendChar(c);
   }

    passwordGlobalVariable.var = passWord;
}

A small side-note: Refrain from using the var word because one can be confused with the C#'s var contextual keyword.

edited Jun 19, 2014 at 16:08

answered Jun 18, 2014 at 20:50

Yair Nevet

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6 Comments

superKing Over a year ago

@Yair Nevet thanks! unfortunately it does not like my quotes. It underlines my "" and the error says Cannot implicitly convert type 'string to 'System.Security.SecureString'

superKing Over a year ago

@Yair Nevet thanks again--I changed that and it underlines passWord on the line passwordGlobalVariable.var = passWord; Error says **Argument 4: cannot convert from 'string' to 'System.Security.SecureString'

Yair Nevet Over a year ago

@superKing you should have no string fields in your data structures.

superKing Over a year ago

@YairNevet you are the man! That certainly did the trick and I hope others can benefit from this answer. I would vote it up if I had enough points. For some reason someone voted down my question. No idea why...anyway thanks again, bud! :D

Yair Nevet Over a year ago

@asadali it is not needed since var is a contextual keyword and not a completly reserved one.

|

Matt · Accepted Answer · 2014-06-18 20:51:27Z

2

The code below create a SecureString from the string var:

   SecureString passWord = new SecureString();
   foreach (char c in var.ToCharArray())
                  passWord.AppendChar(c);

answered Jun 18, 2014 at 20:51

Matt

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2 Comments

superKing Over a year ago

thanks (and sorry as i'm new to coding) but will this make a new variable called passWord? Should I use the passWord variable to store the text in the password field? Will this variable be available globally? Thanks again

Matt Over a year ago

You can keep use the SecureString to store the passoword.

Carlos Rodriguez · Accepted Answer · 2014-06-18 20:51:36Z

0

var secureUsername = new SecureString();
foreach (char c in usernameGlobalVariable.var)
{
    secureUsername.AppendChar(c);
}

var securePassword = new SecureString();
foreach (char c in passwordGlobalVariable.var)
{
    securePassword.AppendChar(c);
}

This will give you two SecureStrings that you can pass into the Process.Start method

answered Jun 18, 2014 at 20:51

Carlos Rodriguez

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2 Comments

superKing Over a year ago

thank you--I tried this, but it underlines var saying A namespace cannot directly contain members such as fields or methods It also underlines SecureString and says Expected class, delegate, enum, interface, or struct

Yair Nevet Over a year ago

Process.Start overloads accepts only one SecureString and it should be a password and not a username.

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