How to use regular expression with a string array

Question

I have a string array

string [] ar = { "net" , "com" , "org"};

and I want the label writes "true" when the user enter a website example ends with a string in the array

I tried this:

   private void timer1_Tick(object sender, EventArgs e)
    {
        foreach ( string ex in ar)
        {
            if (Regex.IsMatch(txtbox.Text, @"^(www\.)([\w]+)\.(" + ex + ")$"))
            {
                lbl.Text = "True";
            }
            else
            {
                lbl.Text = "False";
            }
        }
    }

When I write for example "www.google.com", the label still writes false. Only when I write "www.google.org" the label writes true.

Try lbl.Text = ar.Any(ex => Regex.IsMatch(txtbox.Text, @"^(www\.)([\w]+)\.(" + ex + ")$"))) ? "True" : "False"; instead — juharr
– juharr, Commented Oct 22, 2015 at 15:22

Anton Gogolev · Accepted Answer · 2015-10-22 15:19:27Z

7

You'll need to stop your foreach iteration as soon as you hit the first match. Or, better yet,

lbl.Text = ar.Any(s => Regex.IsMatch(txtbox.Text, "..." + s + "...")) ? "True" : "False"

Plus, be careful with timers in a WinForms applications: you can only safely use System.Windows.Forms.Timer, not System.Threading.Timer.

answered Oct 22, 2015 at 15:19

Anton Gogolev

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Comments

Nazir Ullah · Accepted Answer · 2015-10-22 15:38:28Z

0

You are using foreach loop which are completing its all ittrations, so when ittration is compare with your condition then remove the control from loop e.g. org at the last of array index thatswhy it found at last of the lopp ittrations, edit your code as.

 foreach ( string ex in ar)
        {
            if (Regex.IsMatch(txtbox.Text, @"^(www\.)([\w]+)\.(" + ex + ")$"))
            {
                lbl.Text = "True";
                return;
            }
            else
            {
                lbl.Text = "False";
            }
        }

answered Oct 22, 2015 at 15:38

Nazir Ullah

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