10.11

 

今天通一上午的学习，和下午的复习，让我们学会了一些新的知识。比如：

创建DataTable对象有以下几种方式：

通过构造函数创建: 

无参数构造函数：

DataTable table1=New DataTable() ；

有参数构造函数：

DataTable table1=New DataTable(string tableName) ；

 向DataTable对象中添加列对象

DataColumn colUserID = new DataColumn("USER_ID", Type.GetType("System.Int"));

table1.Columns.Add(colCurrency);

DataColumn colUserName= new DataColumn("USER_NAME", Type.GetType("System.String"));

等；

namespace guowuche

{

    

    public partial class _Default : System.Web.UI.Page

    {

        static int i = 0;

        static int a = 0;

        static int b = 0;

        protected void Page_Load(object sender, EventArgs e)

        {

            

        }

        private void AddRows1(DataTable table1)

        {

            DataRow row = table1.NewRow();

            row["商品名"] = "帽子";

            row["商品概述"] = "帽子10元";

            row["商品数量"] = i;

            row["商品总价"] = i * 10;

            table1.Rows.Add(row);

        }

        private void AddRows2(DataTable table1)

        {

            DataRow row1 = table1.NewRow();

            row1["商品名"] = "椅子";

            row1["商品概述"] = "椅子30元";

            row1["商品数量"] = a;

            row1["商品总价"] = a * 30;

            table1.Rows.Add(row1);

        }

        private void AddRows3(DataTable table1)

        {

            DataRow row2 = table1.NewRow();

            row2["商品名"] = "桌子";

            row2["商品概述"] = "桌子70元";

            row2["商品数量"] = b;

            row2["商品总价"] = b * 70;

            table1.Rows.Add(row2);

        }

        private void initTable(DataTable table1)

        {

            DataColumn dc1 = new DataColumn("商品号",

                Type.GetType("System.Int32"));

            dc1.AutoIncrement = true;  //是自动增长列

            dc1.AutoIncrementSeed = 1; //从1开始增长

            dc1.AutoIncrementStep = 1;    //每次长1

            table1.Columns.Add(dc1);

            DataColumn dc2 = new DataColumn();

            dc2.AllowDBNull = false;

            dc2.MaxLength = 10;

            dc2.Unique = true;  //name列不重复

            dc2.ColumnName = "商品名";

            dc2.DataType = typeof(string);

            table1.Columns.Add(dc2);

            DataColumn dc3 = new DataColumn();

            dc3.AllowDBNull = false;

            dc3.MaxLength = 10;

            dc3.Unique = true;  //name列不重复

            dc3.ColumnName = "商品概述";

            dc3.DataType = typeof(string);

            table1.Columns.Add(dc3);

            DataColumn dc4 = new DataColumn("商品数量",

                Type.GetType("System.Int32"));

            table1.Columns.Add(dc4);

            DataColumn dc5 = new DataColumn("商品总价",

                Type.GetType("System.Int32"));

            table1.Columns.Add(dc5);

            table1.PrimaryKey = new DataColumn[] { dc1 };//主键是商品号

        }

        protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)

        {

        }

        

        protected void Button1_Click(object sender, EventArgs e)

        {

            i = i + 1;

            Label1.Text = i.ToString();

            

        }

        protected void Button2_Click(object sender, EventArgs e)

        {

            a = a + 1;

            Label2.Text = a.ToString();

        }

        protected void Button3_Click(object sender, EventArgs e)

        {

            b = b + 1;

            Label3.Text = b.ToString();

        }

        protected void Button4_Click(object sender, EventArgs e)

        {

            DataTable table1 = new DataTable();

            initTable(table1);

            //AddRows(table1);

            if (i > 0)

            {

                AddRows1(table1);

            }

            if (a > 0)

            {

                AddRows2(table1);

            }

            if (b > 0)

            {

                AddRows3(table1);

            }

            table1.AcceptChanges();

            this.GridView1.DataSource = table1;

            this.GridView1.DataBind();

            Label4.Text = "总额为："+(i * 10 + a * 30 + b * 70).ToString()+"元";

        }

    }

}