C#中DataTable的一些常用操作

  protected void Page_Load(object sender, EventArgs e)    {        //①Create a DataTable        DataTable dt = new DataTable("Table_AX");        //②Add columns for DataTable        //Method 1        dt.Columns.Add("column0", System.Type.GetType("System.String"));        //Method 2        DataColumn dc = new DataColumn("column1", System.Type.GetType("System.Boolean"));        dt.Columns.Add(dc);        //③Add rows for DataTable        //★Initialize the row        DataRow dr = dt.NewRow();        dr["column0"] = "AX";        dr["column1"] = true;        dt.Rows.Add(dr);        //★Doesn't initialize the row        DataRow dr1 = dt.NewRow();        dt.Rows.Add(dr1);        //④Select row        //Search the second row 如果没有赋值,则用is null来select        DataRow[] drs = dt.Select("column1 is null");        DataRow[] drss = dt.Select("column0 = 'AX'");        //⑤Copy DataTable include data        DataTable dtNew = dt.Copy();        //⑥Copy DataTable only scheme        DataTable dtOnlyScheme = dt.Clone();        //⑦Operate one row        //★都是对dt的操作        //Method 1        DataRow drOperate = dt.Rows[0];        drOperate["column0"] = "AXzhz";        drOperate["column1"] = false;        //Method 2        drOperate[0] = "AXzhz";        drOperate[1] = false;        //Method 3        dt.Rows[0]["column0"] = "AXzhz";        dt.Rows[0]["column1"] = false;        //Method 4        dt.Rows[0][0] = "AXzhz";        dt.Rows[0][1] = false;        //⑧Evaluate another DataTable's row to current Datatable        dtOnlyScheme.Rows.Add(dt.Rows[0].ItemArray);        //⑨Use Rowstate        //■■■■■■■■■■■■■■■■■■■■■■■■■■■■        //不知道怎么才能使Row的State变为DataRowState.Deleted        //More further,怎样设置Row的State        //■■■■■■■■■■■■■■■■■■■■■■■■■■■■        if (dt.Rows[0].RowState == DataRowState.Unchanged)        {            //Your logic        }        //⑩Convert to string        System.IO.StringWriter sw = new System.IO.StringWriter();        System.Xml.XmlTextWriter xw = new System.Xml.XmlTextWriter(sw);        dt.WriteXml(xw);        string s = sw.ToString();        //ⅰ.string convert to DataTable【Doesn't achieve it】        //■■■■■■■■■■■■■■■■■■■■■■■■■■■■        //没有把string成功转换为DataTable        ■■已实现,参见追加■■        //■■■■■■■■■■■■■■■■■■■■■■■■■■■■        //DataTable dtConvert = new DataTable();        //System.IO.StringReader stream = new System.IO.StringReader(s);        //System.Xml.XmlReader xtr = new System.Xml.XmlTextReader(stream);        //dtConvert.ReadXml(xtr);        //ⅱ.Filter DataTable        //It's so strange that the second row has been filtered        //the second row show in GridView never        //It means null field will be filter always.        //Filter the all conditions        dt.DefaultView.RowFilter = "column1 <> true";        //dt.DefaultView.RowFilter = "column1 = true";        dt.DefaultView.RowStateFilter = DataViewRowState.Added;        //ⅲ.Sort row        //Stupid method        DataRow[] drsss = dt.Select(String.Empty, "column0 DESC , column1 ASC");        //Clever method        dt.DefaultView.Sort = "column0 , column1 ASC";        //ⅳ.Bind DataTable        //绑定的其实是DefaultView        gvTestDataTable.DataSource = dt;        gvTestDataTable.DataBind();    }//【追加】判断一个字符串是否为DataTable的列名dtInfo.Columns.Contains("AX");//【追加】DataTable与XML的转换protected void Page_Load(object sender, EventArgs e){DataTable dt_AX = new DataTable();//dt_AX.Columns.Add("Sex", typeof(System.Boolean));//DataRow dr = dt_AX.NewRow();//dr["Sex"] = true;//dt_AX.Rows.Add(dr);string xml=ConvertBetweenDataTableAndXML_AX(dt_AX);DataTable dt = ConvertBetweenDataTableAndXML_AX(xml);}public string ConvertBetweenDataTableAndXML_AX(DataTable dtNeedCoveret){System.IO.TextWriter tw = new System.IO.StringWriter();//if TableName is empty, WriteXml() will throw Exception.dtNeedCoveret.TableName=dtNeedCoveret.TableName.Length==0?"Table_AX":dtNeedCoveret.TableName;dtNeedCoveret.WriteXml(tw);dtNeedCoveret.WriteXmlSchema(tw);return tw.ToString();}public DataTable ConvertBetweenDataTableAndXML_AX(string xml){System.IO.TextReader trDataTable = new System.IO.StringReader(xml.Substring(0, xml.IndexOf("<?xml")));System.IO.TextReader trSchema = new System.IO.StringReader(xml.Substring(xml.IndexOf("<?xml")));DataTable dtReturn = new DataTable();dtReturn.ReadXmlSchema(trSchema);dtReturn.ReadXml(trDataTable);return dtReturn;}//【追加】排序的好方法dt.DefaultView.Sort = "ID ,Name ASC";dt=dt.DefaultView.ToTable();