private void Form1_Load(object sender, EventArgs e)
        {
            conn = new SqlConnection("server=.;uid=sa;pwd=;database=Book");
            sda = new SqlDataAdapter("select * from BookInfo",conn);
            sda.Fill(ds, "BookInfo");
            this.dataGridView1.DataSource = ds.Tables[0].DefaultView;

            if (ds.Tables["BookInfo"].Rows.Count == 0)
            {
                this.btnUpdate.Enabled = false;
                this.btnDel.Enabled = false;
            }
        }

        private void btnAdd_Click(object sender, EventArgs e)
        {

            string insCmd = "Insert into BookInfo values(@BookName,@BookAuthor,@BookPrice)";
            //初始化InsertCommand
            sda.InsertCommand = new SqlCommand(insCmd, conn);

            //声明参数并制定数据库的列和版本
            param = sda.InsertCommand.Parameters.Add("@BookName", SqlDbType.VarChar);
            param.SourceColumn = "BookName";
            param.SourceVersion = DataRowVersion.Current;

            param = sda.InsertCommand.Parameters.Add("@BookAuthor", SqlDbType.VarChar);
            param.SourceColumn = "BookAuthor";
            param.SourceVersion = DataRowVersion.Current;

            param = sda.InsertCommand.Parameters.Add("@BookPrice", SqlDbType.Decimal);
            param.SourceColumn = "BookPrice";
            param.SourceVersion = DataRowVersion.Current;

            //如果数据集已更改，则插入记录
            if (ds.HasChanges())
            {
                try
                {
                    //DataAdapter 的 Update() 方法将调用 InsertCommand
                    sda.Update(ds, "BookInfo");
                    MessageBox.Show("信息已插入");
                    this.btnUpdate.Enabled = true;
                    this.btnDel.Enabled = true;
                }
                catch (SqlException ex)
                {
                    MessageBox.Show(ex.Message);
                }

            }
            else
            {
                MessageBox.Show("提供详细信息以添加新记录");
            }


信息始终不能成功录入  最终显示"提供详细信息添加"  代码能编译成功
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