DataTable类Clone方法与Copy方法的区别分析

datatable.clone 方法：克隆 datatable 的结构，包括所有 datatable 架构和约束。

datatable.copy 方法：复制该 datatable 的结构和数据。

我们可以编写如下的程序，进行验证：

        static string connstr = "server=.\\sqlexpress;initial catalog=hr;integrated security=true";

        static void clone()
        {
            using (sqlconnection conn = new sqlconnection(connstr))
            {
                string sql = "select * from emp";
                sqldataadapter da = new sqldataadapter(sql, conn);
                datatable dt = new datatable();
                da.fill(dt);
                datatable dtclone = dt.clone();
                print(dtclone);
            }
        }

        private static void print(datatable dtclone)
        {
            foreach (datacolumn col in dtclone.columns)
            {
                console.write(col.datatype+"\t");
            }
            console.writeline();
            foreach (datarow row in dtclone.rows)
            {
                console.write(row[0] + "\t" + row[1] + "\t" + row[2] + "\n");
            }
            console.writeline();
        }
        static void main(string[] args)
        {
            clone();//仅仅复制表结构
            copy();//复制表结构及数据
            console.readkey();
        }

        private static void copy()
        {
            using (sqlconnection conn = new sqlconnection(connstr))
            {
                string sql = "select * from emp";
                sqldataadapter da = new sqldataadapter(sql, conn);
                datatable dt = new datatable();
                da.fill(dt);
                datatable dtcopy = dt.copy();
                print(dtcopy);
            }
        }
    }