修改内存表中的数据

#region 创建内存表
/// <summary>
/// 创建内存表
/// </summary>
public static void CreateTable(string TableName)
{
    DataTable GoodsTable=new DataTable();
    GoodsTable.Columns.Add(new DataColumn("Rid",typeof(int)));
    GoodsTable.Columns.Add(new DataColumn("GoodsName",typeof(string)));
    GoodsTable.Columns.Add(new DataColumn("GoodsNum",typeof(string)));
    GoodsTable.Columns.Add(new DataColumn("Attribute",typeof(string)));
    GoodsTable.Columns.Add(new DataColumn("Description",typeof(string)));
    GoodsTable.Columns.Add(new DataColumn("State",typeof(string)));

    GoodsTable.Columns["Rid"].AllowDBNull=false;
    GoodsTable.Columns["Rid"].AutoIncrement=true;
    GoodsTable.Columns["Rid"].AutoIncrementSeed=0;
    GoodsTable.Columns["Rid"].AutoIncrementStep=1;
    GoodsTable.Columns["Rid"].Unique=true;

    System.Web.HttpContext.Current.Session[TableName]=GoodsTable;
    GoodsTable.Dispose();
}
#endregion

#region 修改内存表数据的状态信息
public void UpdateRows(string TableName,string Rid,string State)
{
    if(System.Web.HttpContext.Current.Session[TableName]!=null)
    {
        DataTable Dt=(DataTable)System.Web.HttpContext.Current.Session[TableName];
        for(int i=0;i<Dt.Rows.Count;i++)
        {
            if(Dt.Rows[i][0].ToString()==Rid)
                        {
                Dt.Rows[i][5]=State;  //这一处该怎么修改，才可以更新内存表中的数据？
                           }
        }
        System.Web.HttpContext.Current.Session[TableName]=Dt;
        Dt.Dispose();
    }
}
#endregion

用SqlDataAdapter.Update 方法或 
 DataTable.AcceptChanges方法可更新表数据

Dt.AcceptChange(); 
 加上这个方法


//----------------------------------------------------------------------------------------------
DataTable myTable=DS.Tables["表名"];     --->添加
  DataRow myNewRow=myTable.NewRow();
  myNewRow["你要添加的列名"]="值";
  myNewRow["你要添加的列名"]="值";
  myTable.Rows.Add(myNewRow);
  dg2.DataSource=myTable.DefaultView;
  dg2.DataBind(); //将新添的数据邦定


DataRow[] myNewRow2=myTable.Select("id_jldw=11 AND name_jldw='内容'");   ----->修改
  //myNewRow2[0]["要修改的列名"]=值;
  myNewRow2[0]["要修改的列名"]=值;
  myNewRow2[0]["要修改的列名"]=值;
  dg3.DataSource=myTable.DefaultView;
  dg3.DataBind();//将新添的数据邦定



   myTable.Rows[0].Delete();//删除第一行             ---->删除
  dg4.DataSource=myTable.DefaultView;
  dg4.DataBind();
//---------------------------------------------------------------------------------------------------

DataTable workTable  = new DataTable();
workTable.Columns.Add("LastName", typeof(String));

workTable.ColumnChanged += 
  new DataColumnChangeEventHandler(OnColumnChanged);

DataRow workRow = workTable.NewRow();
workRow[0] = "Smith";
workTable.Rows.Add(workRow);

workRow.BeginEdit();
// Causes the ColumnChanged event to write a message and cancel the edit.
workRow[0] = "";     
workRow.EndEdit();

// Displays "Smith, New".
Console.WriteLine("{0}, {1}", workRow[0], workRow.RowState);  

protected static void OnColumnChanged(
  Object sender, DataColumnChangeEventArgs args)
{
  if (args.Column.ColumnName == "LastName")
    if (args.ProposedValue.ToString() == "")
    {
      Console.WriteLine("Last Name cannot be blank. Edit canceled.");
      args.Row.CancelEdit();
    }
}
//--------------------------------------------------------------------------------------------------
for (int i = 0; i < DataTable.Rows.Count; i++)
            ...{
                 DataRow dt = DataTable.Rows[i];
                 dt.BeginEdit();
                 dt["Column"] = "value";
                 dt.EndEdit();
             }

//-----------------------------------------------------------------------------------------------------

添加： 

DataTable cart = new DataTable();
        if (Session["shopingcar"] == null)
        {
            cart.Columns.Add("商品编号", typeof(int));
            cart.Columns.Add("商品名称", typeof(string));
            cart.Columns.Add("商品单价", typeof(double));
            cart.Columns.Add("商品数量", typeof(int));
            Session["shopingcar"] = cart;
        }
        cart = (DataTable)Session["shopingcar"];
        DataRow dr = cart.NewRow();
        dr["商品编号"] = model.ID;
        dr["商品名称"] = model.产品名称;
        dr["商品单价"] = double.Parse(model.价格);
        dr["商品数量"] = 1;
        cart.Rows.Add(dr);

 

修改：

必须这样：
DataRow   row=myTable.Rows[0];
row.BeginEdit();
row.[ "userName "]= "aa ";
row[ "pwd "]= "121 ";
row.EndEdit();

 

删除某行
代码如下：
删除第二行
myTable.Rows.RemoveAt(1);

//--------------------------------------------------------------------------------------------------------------

有时需要在内存中创建一个临时表，用以实现特殊的显示和查询要求，而Datatable 就是经常用到的一个工具，以下是本人的一些测试代码，实现了Datatable的动态创建和查询、修改，由于时间仓促，写得比较乱，不过懂asp.net 和 C#的应该也能看懂，凑合着看吧，希望对大家有所帮助。

 using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class Datatable : System.Web.UI.Page
{
    protected DataTable dtYxzt;
    protected DataRow row;
    protected DataRow[] rows;
    private bool IsExist(int id1, int id2)
    {      
        rows = dtYxzt.Select("id1=" + id1 + " and id2=" + id2);
        if (rows.Length > 0)
            return true ;
        else
            return false;
    }
    protected void Page_Load(object sender, EventArgs e)
    {
        Int16 id1, id2;
        dtYxzt = new DataTable("yxzt");
        dtYxzt.Columns.Add("id1", typeof(Int16));
        dtYxzt.Columns.Add("id2", typeof(Int16));
        dtYxzt.Columns.Add("sglx", typeof(string));
        dtYxzt.Columns.Add("cb", typeof(string));
        dtYxzt.Columns.Add("wsg", typeof(Int32));
        dtYxzt.Columns.Add("zzsg", typeof(Int32));
        dtYxzt.Columns.Add("sgwc", typeof(Int32));

        row = dtYxzt.NewRow();
        row["id1"] = 1;
        row["id2"] = 1;
        row["sglx"] = "新井射孔";
        row["cb"] = "采油二厂";
        row["wsg"] = 66;
        row["zzsg"] = 66;
        row["sgwc"] = 66;
        dtYxzt.Rows.Add(row);
        row = dtYxzt.NewRow();
        row["id1"] = 1;
        row["id2"] = 2;
        row["sglx"] = "新井射孔2";
        row["cb"] = "采油二厂2";
        row["wsg"] = 66;
        row["zzsg"] = 66;
        row["sgwc"] = 66;
        dtYxzt.Rows.Add(row);
        row = dtYxzt.NewRow();
        row["id1"] = 1;
        row["id2"] = 3;
        row["sglx"] = "新井射孔3";
        row["cb"] = "采油二厂3";
        row["wsg"] = 66;
        row["zzsg"] = 66;
        row["sgwc"] = 66;
        dtYxzt.Rows.Add(row);
        dtYxzt.AcceptChanges();