richtextbox写入SQL的问题

C# code

        private void button1_Click(object sender, EventArgs e)        {            conn.Open();            string sql = "insert into test values('" + richTextBox1.Rtf +"')";            SqlCommand cmd = new SqlCommand(sql, conn);            cmd.ExecuteNonQuery();            cmd = new SqlCommand("select   *   from   test ", conn);            SqlDataReader dr = cmd.ExecuteReader();            while (dr.Read())            {                richTextBox2.Rtf = dr.GetValue(1).ToString();            }            dr.Close();            conn.Close();        }

提示下面语句中'cb'附近有语法错误,是转义字符的问题吗,应该怎么修改?
"insert into test values('{\\rtf1\\ansi\\ansicpg936\\deff0\\deflang1033\\deflangfe2052{\\fonttbl{\\f0\\fnil\\fcharset134 \\'cb\\'ce\\'cc\\'e5;}}\r\n\\viewkind4\\uc1\\pard\\lang2052\\f0\\fs18 1111\\par\r\n}\r\n')"

[解决办法]
richTextBox1.Text？
[解决办法]

探讨

C# code

private void button1_Click(object sender, EventArgs e)
{
conn.Open();
string sql = "insert into test values('" + richTextBox1.Rtf +"')";
S……

[解决办法]
richTextBox1.Rtf.Replace("'","''")

说什么好呢？！凡是不知道将一个单引号变成两个单引号的，连起码的t-sql语法都没有学会，怎么进行数据库编程啊。