//Datatable 的用法 /* * 1、基本的DataTable列行增加 * 2、排序、篩選等用法 * 3、xml之間的轉化 * 4、Json之間的轉換 * 5、list之間的轉換 * 6、實體類之間的轉換 */
今天把常用的Datatable整理了一下,雖然平時經常用這個,但是沒有總結過,這次剛好有點時間做個筆記;
先看第一個:
DataTable dt = new DataTable(); dt.Columns.Add("ID",typeof(int)); dt.Columns.Add("Name",typeof(string)); dt.Columns.Add("Sex",typeof(string)); DataRow dr = dt.NewRow(); dr["ID"] = "1"; dr["Name"] = "張三"; dr["Sex"] = "男"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["ID"] = "2"; dr["Name"] = "李四"; dr["Sex"] = "男"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["ID"] = "12"; dr["Name"] = "旺旺"; dr["Sex"] = "男"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["ID"] = "22"; dr["Name"] = "王五"; dr["Sex"] = "男"; dt.Rows.Add(dr); dr = dt.NewRow(); dr["ID"] = "32"; dr["Name"] = "趙六"; dr["Sex"] = "男"; dt.Rows.Add(dr);
第二個:按照其中已知的某一列排序(根據實際列的類型需要修改代碼)
static public DataTable DtSortA(DataTable Dt, string column) { DataTable dtNew = Dt.Clone(); dtNew.Columns[column].DataType = typeof(DateTime); foreach (DataRow s in Dt.Rows) { dtNew.ImportRow(s);//導入舊數據 } dtNew.DefaultView.Sort = column + " desc"; dtNew = dtNew.DefaultView.ToTable(); return dtNew; } static public DataTable DtSortB(DataTable Dt, string column) { DataTable dtNew = Dt.Clone(); foreach (DataRow item in Dt.AsEnumerable().OrderByDescending(a => Convert.ToDateTime(a[column]))) { dtNew.ImportRow(item); } return dtNew; }
DataTable dt_order_soon = dt_invest.Clone();//克隆表 if (dt_invest != null && dt_invest.Rows.Count > 0) { DataRow[] dt_soon = dt_invest.Select("1=1");//篩選條件 for (int e = 0; e < dt_soon.Length; e++) { var day = new JBLProCompute.InComeCount().ReturnDays(DateTime.Now, Convert.ToDateTime(dt_soon[e]["DateOver"].ToString())); if (day >= 0 && day <= 7) { dt_order_soon.ImportRow(dt_soon[e]); } }
}
DataTable dt = new DataTable(); dt.Columns.Add("ID", typeof(int));//Type.GetType("System.String") dt.Columns.Add("Name",typeof(string)); dt.Columns.Add("Sex",typeof(string)); DataRow dr = dt.NewRow(); dr["ID"] = "1"; dr["Name"] = "張三"; dr["Sex"] = "男"; dt.Rows.Add(dr); DataTable ddt = new DataTable(); //輸出指定的列數據 ddt= dt.DefaultView.ToTable(false,new string[] {"ID","Name"});
第三:
DataTable dt = new DataTable(); dt.Columns.Add("ID", typeof(int));//Type.GetType("System.String") dt.Columns.Add("Name",typeof(string)); dt.Columns.Add("Sex",typeof(string)); DataRow dr = dt.NewRow(); dr["ID"] = "1"; dr["Name"] = "張三"; dr["Sex"] = "男"; dt.Rows.Add(dr);////想要輸出xml格式,當前的Datatable表必須要有表名 dt.TableName = "myData";//添加Datatable表名才能輸出xml格式 System.IO.StringWriter dsw = new System.IO.StringWriter(); System.Xml.XmlTextWriter xw = new System.Xml.XmlTextWriter(dsw); dt.WriteXml(xw); string s = dsw.ToString(); //將xml格式轉成Datatable格式,直接是xml格式的字符串最外層是根節點,第二層是表名,三層是字段和數據 string strxml = @"<xml><Login><ID>1</ID><Name>小明</Name></Login><Login><ID>2</ID><Name>小萬</Name></Login></xml>";
//第二種是文件讀入xml
XmlDocument docddd=new XmlDocument();
docddd.Load(Server.MapPath("/datatable.xml"));
DataTable dt_xml = ConvertXMLToDataSet(docddd.InnerXml).Tables[0];