How do I check if the URL entered by user is right format - this is not working

textBox1.Text!= "@" ^ (\b(http | ftp | https):(\/\/|\\\\)[\w\-_]+(\.[\w\-_]+)+([\w\-\.,@?^=% &:/ ~\+#]*[\w\-\@?^=%&/~\+#])?|\bwww\.[^\s])");

private void Button_Click(object sender, EventArgs e)
       {
           richTextBox1.Visible = true;
           richTextBox1.Clear();

            if (textBox1.TextLength == 0 || textBox1.Text!= "@" ^ (\b(http | ftp | https):(\/\/|\\\\)[\w\-_]+(\.[\w\-_]+)+([\w\-\.,@?^=% &:/ ~\+#]*[\w\-\@?^=%&/~\+#])?|\bwww\.[^\s])");

           {
               string message2 = "Status Code";
               string caption2 = "300 Bad Request";
               MessageBoxButtons buttons2 = MessageBoxButtons.OK;
               DialogResult result2;
               result2 = MessageBox.Show(message2, caption2, buttons2);
               richTextBox1.Clear();
           }

           else
           {

                   HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(this.textBox1.Text);

                   using (HttpWebResponse myHttpWebResponse = (HttpWebResponse)myRequest.GetResponse())
                   {
                       if (myHttpWebResponse.StatusCode == HttpStatusCode.OK)
                       {
                           string message = "200 OK";
                           string caption = "Status Code";
                           MessageBoxButtons buttons = MessageBoxButtons.OK;
                           DialogResult result;

                           // Displays the MessageBox.
                           result = MessageBox.Show(message, caption, buttons);

                           Stream streamResponse = myHttpWebResponse.GetResponseStream();

                           // Get stream object
                           StreamReader streamRead = new StreamReader(streamResponse);

                           Char[] readBuffer = new Char[256];
                           // Read from buffer
                           int count = streamRead.Read(readBuffer, 0, 256);
                           while (count > 0)
                           {
                               // get string
                               String resultData = new String(readBuffer, 0, count);

                               // Write the data
                               richTextBox1.Text += (resultData);

                               // Read from buffer
                               count = streamRead.Read(readBuffer, 0, 256);

                           }// Release the response object resources.
                           streamRead.Close();
                           streamResponse.Close();
                           myHttpWebResponse.Close();
                       }