求高手完善 dataGridView 代码.

问题：
1.此代码第一次修改正常.
2.保存后再次修改，就会提示：违反并发性: UpdateCommand 影响了预期 1 条记录中的 0 条GOOGLE了下大多是说
1.表里设置了自动编号的ID为主键（经过修改尝试--和此处无关）
2.无空值（也没关系）请教，稍稍改动下代码帮我完善这个GridView吧！Winform里关键代码        SqlConnection EGG;
        SqlDataAdapter adapter;
        private void Form1_Load(object sender, EventArgs e)
        {                   
            // TODO: 这行代码将数据加载到表“eGG1.Curriculum”中。您可以根据需要移动或移除它。
            this.curriculumTableAdapter.Fill(this.eGG1.Curriculum);
            EGG = new SqlConnection("server=localhost;database=EGG;uid=sa;pwd=111111");
            SqlDataAdapter sda = new SqlDataAdapter("select * from Curriculum", EGG);
            DataSet ds = new DataSet();
            sda.Fill(ds);
            dataGridView1.DataSource = ds.Tables[0];
            dataGridView1.RowHeadersVisible = false;
            for (int i = 0; i < dataGridView1.ColumnCount; i++)
            {
                dataGridView1.Columns[i].Width = 84;
            }
            dataGridView1.Columns[0].ReadOnly = false;
            button1.Enabled = true ;          
        }        private DataTable dbEGG(string strSql)
        {
            this.EGG.Open();
            this.adapter = new SqlDataAdapter(strSql, EGG);
            DataTable dtSelect = new DataTable();
            int rnt = this.adapter.Fill(dtSelect);
            EGG.Close();          
            return dtSelect;
        }        private Boolean dbUpdate()
        {
            string strSpl = "select * from Curriculum";
            DataTable dbUpdate = new DataTable();
            dbUpdate = this.dbEGG(strSpl);
            dbUpdate.Rows.Clear();
            DataTable dtShow = new DataTable();
            dtShow = (DataTable)this.dataGridView1.DataSource;
            for (int i = 0; i < dtShow.Rows.Count; i++)
            {
                dbUpdate.ImportRow(dtShow.Rows[i]);
            }
            try
            {
                this.EGG.Open();
                SqlCommandBuilder CommandBuilder;
                CommandBuilder = new SqlCommandBuilder(this.adapter);
                this.adapter.Update(dbUpdate);
                this.EGG.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message.ToString());
                return false;
            }
            dbUpdate.AcceptChanges();
            return true;
        }        private void button3_Click(object sender, EventArgs e)
        {           
            if (dbUpdate())
            {
                MessageBox.Show("修改成功！");
            }
            
        }