(11)Sort row
dt.DefaultView.Sort = "ID ,Name ASC";
dt=dt.DefaultView.ToTable();
(12)Bind DataTable
//绑定的其实是DefaultView
gvTestDataTable.DataSource = dt;
gvTestDataTable.DataBind();
(13)judge the DataTable’s Column name is a string
//判断一个字符串是否为DataTable的列名
dtInfo.Columns.Contains("AX");
(14)DataTable convert to XML and XML convert to DataTable
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; } |
(15)在DataTable中执行查询返回DataTable;
方法1:
// <summary>
// 执行DataTable中的查询返回新的DataTable
// </summary>
// dt 是源数据DataTable
// condition 是查询条件
DataTable newdt = new DataTable();
newdt = dt.Clone(); // 克隆dt 的结构,包括所有 dt 架构和约束,并无数据;
DataRow[] rows = dt.Select(conditions); // 从dt 中查询符合条件的记录;
foreach (DataRow row in rows) // 将查询的结果添加到dt中;
{
newdt.Rows.Add(row.ItemArray);
}
方法2:
DataTable newdt = new DataTable();
newdt=dt.Clone();
DataRow[] dr = dt.Select(condition);
for(int i=0;i<dr.Length;i++)
{
newdt.ImportRow((DataRow)dr[i]);
}
方法3:
DataTable newdt = new DataTable();
dt.DefaultView.RowFilter = "conditions";
newdt =dt.DefaultView.ToTable();
(16)删除DataTable中的行:
删除DataTable中的行三种方法:(DataTable.Rows.Remove(DataRow dr)、DataTable.Rows.RemoveAt(i)、DataRow.Delete())
删除DataTable中的行要注意索引问题,一般有两种方法:
1】用for循环时,注意计数器初始值为表长,自减循环。DataTable.Rows.RemoveAt(i)就要注意。
2】用DataTable的Select方法,注意该方法的参数是字符串筛选器
3】Delete()之后需要datatable.AccepteChanges()方法确认完全删除,因为Delete()只是将相应列的状态标志为删除,还可以通过datatable.RejectChanges()回滚,使该行取消删除。若要删除多行,可以连续用Delete(),然后采用AccepteChanges()方法确认删除。