C# 手动编写 DataSet，DataTable 及遍历DataSet中的数据

一。手动编写DataSet：

   有时候不想从数据库导出 DataSet，或者有其他的需要，要将数据库里的DataSet包装成另一个样子，这个时候，了解DataSet的内部结构就非常必要。DataSet的构造也比较简单：

   一个DataSet里头有很多 DataTable

   一个DataTable里头有很多  DataColumn 和很多 DataRow

   从名字就能猜到它们大概是干什么的。。

   ok，举例说明吧~

 

   private DataSet CreatTable()

        {

            //创建一个Table 和 DataSet

            DataTable table = new DataTable();

            DataSet ds = new DataSet();

            //创建一个列

            DataColumn column1 = new DataColumn();

            column1.DataType = System.Type.GetType("System.String");

            column1.ColumnName = "Periord";

            //创建一个列

            DataColumn column2 = new DataColumn();

            column2.DataType = System.Type.GetType("System.Int32");

            column2.ColumnName = "Total";

            //

            //把列添加进去

            table.Columns.Add(column1);

            table.Columns.Add(column2);

            //创建一个行

            DataRow row1 = table.NewRow();

            row1["Periord"] = "Monday";

            row1["Total"] = 0;

            DataRow row2 = table.NewRow();

            row2["Periord"] = "Tuesday";

            row2["Total"] = 0;

            DataRow row3 = table.NewRow();

            row3["Periord"] = "Wednesday";

            row3["Total"] = 0;

            DataRow row4 = table.NewRow();

            row4["Periord"] = "Thursday";

            row4["Total"] = 0;

            DataRow row5 = table.NewRow();

            row5["Periord"] = "Friday";

            row5["Total"] = 0;

            DataRow row6 = table.NewRow();

            row6["Periord"] = "Saturday";

            row6["Total"] = 0;

            DataRow row7 = table.NewRow();

            row7["Periord"] = "Sunday";

            row7["Total"] = 0;

            //把行添加进去

            table.Rows.Add(row1);

            table.Rows.Add(row2);

            table.Rows.Add(row3);

            table.Rows.Add(row4);

            table.Rows.Add(row5);

            table.Rows.Add(row6);

            table.Rows.Add(row7);

            //把 Table添加到 DataSet 里面去

            ds.Tables.Add(table);

            return ds;

        }

二。遍历DataSet中的元素

   贴一个不错的网上的代码

   DataSet2 ds = new DataSet2();

   SqlDataAdapter da1 = new SqlDataAdapter(str, conn);

   da1.Fill(ds, "table");  

   //已经装载到DataSet数据集中了   

   for (int k = 0; k < ds.Tables["table"].Rows.Count; k++)

                {

                    for (int j = 0; j < ds.Tables["table"].Columns.Count; j++)

                    {

                        if (ds.Tables["table"].Rows[k]["emergency"].ToString().Trim() == "1")

                        {

                            ds.Tables["table"].Rows[k]["emergency"] = "合格";

                        }

                        else if (ds.Tables["table"].Rows[k]["emergency"].ToString().Trim() == "0")

                        {

                            //emergency = "处置";

                            ds.Tables["table"].Rows[k]["emergency"] = "处置";

                        }

                    }

                } 

   ds.AcceptChanges();