C# string extract tag method

This extracts a tagged string. For example, string findTagValue = extractTag ("Foo", "", ""); This would fetch Foo.

    private string extractTag(string original, string beginTag, string endTag)
    {
        string retVal = string.Empty;
        int begin = original.IndexOf(beginTag);
        int end = -1;
        if (begin > 0)
        {
            end = original.IndexOf(endTag, begin);
        }
        if ((begin > 0))
        {
            if ((end > begin))
            {
                retVal = original.Substring((begin+beginTag.Length), (end - begin-endTag.Length));
            }
        }
        return retVal;
    }