C# character counter when writing to new line
<p>Basically I'm trying to read a really big text file and when the charecters of the line reach X amount write to a new line, but I can't seem to get the character count to work.  Any help is appreciated!</p>

<pre><code>using (FileStream fs = new FileStream(betaFilePath,FileMode.Open))
    using (StreamReader rdr = new StreamReader(fs))
    {
        while (!rdr.EndOfStream)
        {
            string betaFileLine = rdr.ReadLine();
            int stringline = 0;
            if (betaFileLine.Contains("þTEMP"))
            {
                //sb.AppendLine(@"C:\chawkster\workfiles\New Folder\GEL_ALL_PRODUCTS_CONCORD2.DAT");
                string checkline = betaFileLine.Length.ToString();
                foreach (string cl in checkline)
                {
                    stringline++;
                    File.AppendAllText(@"C:\chawkster\workfiles\New Folder\GEL_ALL_PRODUCTS_CONCORD3.DAT", cl);
                    if(stringline == 1200)
                    {
                        File.AppendAllText(@"C:\chawkster\workfiles\New Folder\GEL_ALL_PRODUCTS_CONCORD3.DAT","\n");
                        stringline = 0;
                    }
                }                           
            }
        }
</code></pre>

<p>Error:</p>

<pre><code>foreach (string cl in checkline)
Error   1   Cannot convert type 'char' to 'string'  
</code></pre>
