Check Particulare file Format are in the Folder using C#.Net

public static int chknofiles;

public static bool chkfileextention(string filepath, string fileextension)
        {

            string[] fsDir = Directory.GetFiles(filepath);
            foreach (string f in fsDir)
            {
                string fName = f.Substring(filepath.Length + 1);
                string[] fileExt = fName.Split('.');
                if (fileExt[1] == fileextension)
                {
                    chknofiles = chknofiles + 1;
                }
            }
            if (chknofiles > 1)
            {
                chkfileextension = true;
            }
            else
            {
                chkfileextension = false;
            }
            return chkfileextension;
        }

 bool chk = chkfileextention(txtBrowsFile.Text, "pcl");
            if (chk)
            {
                MessageBox.Show("true");

            }
            else
            {
                   MessageBox.Show("false");
            }