C＃Windows表单登录程序

Question

Im looking to create a simple windows login form i have the files loading form a text file on my c drive, but when i compare the string the the list i have create and its not working correctly this is my code

    private void button1_Click(object sender, EventArgs e)
    {
        const string f = "C:/Users.txt";

        List<string> lines = new List<string>();

        string userNameInput = Convert.ToString(userBox);

        using (StreamReader r = new StreamReader(f))
        {

            string line;
            while ((line = r.ReadLine()) != null)
            {
                lines.Add(line);
            }
        }
        for (int i = 0; i < lines.Count; i++)
        {
            MessageBox.Show(lines[i]);
            MessageBox.Show(userNameInput);
            if (lines[i] == userNameInput)
            {
                MessageBox.Show("correct");
            }
            else
            {
                MessageBox.Show("Not Correct");
            }

        }
    }
}

}

Answer 1

You can do as below

if (File.ReadAllLines("C:/Users.txt").Select(x=>x.Trim()).Contains(userBox.Text.Trim()))
{
    MessageBox.Show("correct");
}
else
{
    MessageBox.Show("Not Correct");
}

What it does is read all lines from your file and trim each line and compare with input text. if there is matching line you will receive message as correct

Answer 2

You could simply a bit with:

        const string f = @"C:\Users.txt";
        string[] lines = System.IO.File.ReadAllLines(f);
        if (Array.IndexOf(lines, userBox.Text) != -1)
        {
            MessageBox.Show("correct");
        }
        else
        {
            MessageBox.Show("Not Correct");
        }

Answer 3

Why use this?

string userNameInput = Convert.ToString(userBox);

This could be used and is easier to get the text of the textBox by its self.

string userNameInput = userBox.text;

And this should should help with what you need.

const string f = "C:/Users.txt";
string file = System.IO.File.ReadAllText(f);

string[] strings = Regex.Split(file.TrimEnd(), @"\r\n");

foreach (String str in strings)
{
    // Do something with the string. Each string comes in one at a time.
    // So this will be run like for but is simple, and easy for one object.
    // str = the string of the line.
    // I shall let you learn the rest it is fairly easy. here is one tip
    lines.Add(str);
}
// So something with lines list

I hope I had helped!