DataTable使用

==========  方法一

DataTable  tblDatas = newDataTable("Datas");

DataColumn dc = null;

//赋值给dc，是便于对每一个datacolumn的操作

dc =tblDatas.Columns.Add("ID",Type.GetType("System.Int32"));

dc.AutoIncrement= true;//自动增加

dc.AutoIncrementSeed = 1;//起始为1

dc.AutoIncrementStep = 1;//步长为1

dc.AllowDBNull = false;//

dc = tblDatas.Columns.Add("Product",Type.GetType("System.String"));

dc = tblDatas.Columns.Add("Version",Type.GetType("System.String"));

dc = tblDatas.Columns.Add("Description",Type.GetType("System.String"));

DataRow newRow;

newRow = tblDatas.NewRow();

newRow["Product"] = "大话西游";

newRow["Version"] = "2.0";

newRow["Description"] = "我很喜欢";

tblDatas.Rows.Add(newRow);

newRow = tblDatas.NewRow();

newRow["Product"] = "梦幻西游";

newRow["Version"] = "3.0";

newRow["Description"] = "比大话更幼稚";

tblDatas.Rows.Add(newRow);

==========  方法二

DataTable tblDatas = newDataTable("Datas");

tblDatas.Columns.Add("ID", Type.GetType("System.Int32"));

tblDatas.Columns[0].AutoIncrement = true;

tblDatas.Columns[0].AutoIncrementSeed = 1;

tblDatas.Columns[0].AutoIncrementStep = 1;

tblDatas.Columns.Add("Product",Type.GetType("System.String"));

tblDatas.Columns.Add("Version",Type.GetType("System.String"));

tblDatas.Columns.Add("Description",Type.GetType("System.String"));

tblDatas.Rows.Add(newobject[]{null,"a","b","c"});

tblDatas.Rows.Add(newobject[] { null, "a", "b", "c" });

tblDatas.Rows.Add(new object[] { null, "a", "b", "c" });

tblDatas.Rows.Add(new object[] { null, "a", "b", "c" });

tblDatas.Rows.Add(new object[] { null, "a", "b", "c" });

==========  方法三

DataTable table = new DataTable ();

//创建table的第一列

DataColumn priceColumn = new DataColumn();

//该列的数据类型

priceColumn.DataType = System.Type.GetType("System.Decimal");

//该列得名称

priceColumn.ColumnName = "price";

//该列得默认值

priceColumn.DefaultValue =50;

// 创建table的第二列

DataColumn taxColumn = new DataColumn();

taxColumn.DataType = System.Type.GetType("System.Decimal");

//列名

taxColumn.ColumnName = "tax";

//设置该列得表达式，用于计算列中的值或创建聚合列

taxColumn.expression_r_r = "price *0.0862";

// Create third column.

DataColumn totalColumn = new DataColumn();

totalColumn.DataType = System.Type.GetType("System.Decimal");

totalColumn.ColumnName = "total";

//该列的表达式，值是得到的是第一列和第二列值得和

totalColumn.expression_r_r = "price + tax";

// 将所有的列添加到table上

table.Columns.Add(priceColumn);

table.Columns.Add(taxColumn);

table.Columns.Add(totalColumn);

//创建一行

DataRow row = table.NewRow();

//将此行添加到table中

table.Rows.Add(row);

//将table放在试图中

DataViewview = new DataView(table);

dg.DataSource = view;

dg.DataBind();