C#中DataTable的一些常用操作

1protected void Page_Load(object sender, EventArgs e)
2    {
3        //①Create a DataTable
4        DataTable dt = new DataTable("Table_AX");
5
6        //②Add columns for DataTable
7        //Method 1
8        dt.Columns.Add("column0", System.Type.GetType("System.String"));
9        //Method 2
10        DataColumn dc = new DataColumn("column1", System.Type.GetType("System.Boolean"));
11        dt.Columns.Add(dc);
12
13        //③Add rows for DataTable
14        //★Initialize the row
15        DataRow dr = dt.NewRow();
16        dr["column0"] = "AX";
17        dr["column1"] = true;
18        dt.Rows.Add(dr);
19        //★Doesn't initialize the row
20        DataRow dr1 = dt.NewRow();
21        dt.Rows.Add(dr1);
22
23        //④Select row
24        //Search the second row 如果没有赋值,则用is null来select
25        DataRow[] drs = dt.Select("column1 is null");
26        DataRow[] drss = dt.Select("column0 = 'AX'");
27
28
29        //⑤Copy DataTable include data
30        DataTable dtNew = dt.Copy();
31
32        //⑥Copy DataTable only scheme
33        DataTable dtOnlyScheme = dt.Clone();
34
35        //⑦Operate one row
36        //★都是对dt的操作
37        //Method 1
38        DataRow drOperate = dt.Rows[0];
39        drOperate["column0"] = "AXzhz";
40        drOperate["column1"] = false;
41        //Method 2
42        drOperate[0] = "AXzhz";
43        drOperate[1] = false;
44        //Method 3
45        dt.Rows[0]["column0"] = "AXzhz";
46        dt.Rows[0]["column1"] = false;
47        //Method 4
48        dt.Rows[0][0] = "AXzhz";
49        dt.Rows[0][1] = false;
50
51        //⑧Evaluate another DataTable's row to current Datatable
52        dtOnlyScheme.Rows.Add(dt.Rows[0].ItemArray);
53
54        //⑨Use Rowstate
55        //■■■■■■■■■■■■■■■■■■■■■■■■■■■■
56        //不知道怎么才能使Row的State变为DataRowState.Deleted
57        //More further,怎样设置Row的State
58        //■■■■■■■■■■■■■■■■■■■■■■■■■■■■
59        if (dt.Rows[0].RowState == DataRowState.Unchanged)
60        {
61            //Your logic
62        }
63
64        //⑩Convert to string
65        System.IO.StringWriter sw = new System.IO.StringWriter();
66        System.Xml.XmlTextWriter xw = new System.Xml.XmlTextWriter(sw);
67        dt.WriteXml(xw);
68        string s = sw.ToString();
69
70        //ⅰ.string convert to DataTable【Doesn't achieve it】
71        //■■■■■■■■■■■■■■■■■■■■■■■■■■■■
72        //没有把string成功转换为DataTable        ■■已实现,参见追加■■
73        //■■■■■■■■■■■■■■■■■■■■■■■■■■■■
74        //DataTable dtConvert = new DataTable();
75        //System.IO.StringReader stream = new System.IO.StringReader(s);
76        //System.Xml.XmlReader xtr = new System.Xml.XmlTextReader(stream);
77        //dtConvert.ReadXml(xtr);
78
79        //ⅱ.Filter DataTable
80        //It's so strange that the second row has been filtered
81        //the second row show in GridView never
82        //It means null field will be filter always.
83        //Filter the all conditions
84        dt.DefaultView.RowFilter = "column1 <> true";
85        //dt.DefaultView.RowFilter = "column1 = true";
86
87        dt.DefaultView.RowStateFilter = DataViewRowState.Added;
88
89        //ⅲ.Sort row
90        //Stupid method
91        DataRow[] drsss = dt.Select(String.Empty, "column0 DESC , column1 ASC");
92        //Clever method
93        dt.DefaultView.Sort = "column0 , column1 ASC";
94
95        //ⅳ.Bind DataTable
96        //绑定的其实是DefaultView
97        gvTestDataTable.DataSource = dt;
98        gvTestDataTable.DataBind();
99    }
100
101	//【追加】判断一个字符串是否为DataTable的列名
102	dtInfo.Columns.Contains("AX");
103	//【追加】DataTable与XML的转换
104	protected void Page_Load(object sender, EventArgs e)
105	{
106		DataTable dt_AX = new DataTable();
107
108		//dt_AX.Columns.Add("Sex", typeof(System.Boolean));
109		//DataRow dr = dt_AX.NewRow();
110		//dr["Sex"] = true;
111		//dt_AX.Rows.Add(dr);
112
113		string xml=ConvertBetweenDataTableAndXML_AX(dt_AX);
114		DataTable dt = ConvertBetweenDataTableAndXML_AX(xml);
115	}
116
117	public string ConvertBetweenDataTableAndXML_AX(DataTable dtNeedCoveret)
118	{
119		System.IO.TextWriter tw = new System.IO.StringWriter();
120		//if TableName is empty, WriteXml() will throw Exception.
121		dtNeedCoveret.TableName=dtNeedCoveret.TableName.Length==0?"Table_AX":dtNeedCoveret.TableName;
122		dtNeedCoveret.WriteXml(tw);
123		dtNeedCoveret.WriteXmlSchema(tw);
124		return tw.ToString();
125	}
126
127	public DataTable ConvertBetweenDataTableAndXML_AX(string xml)
128	{
129		System.IO.TextReader trDataTable = new System.IO.StringReader(xml.Substring(0, xml.IndexOf("<?xml")));
130		System.IO.TextReader trSchema = new System.IO.StringReader(xml.Substring(xml.IndexOf("<?xml")));
131		DataTable dtReturn = new DataTable();
132		dtReturn.ReadXmlSchema(trSchema);
133		dtReturn.ReadXml(trDataTable);
134		return dtReturn;
135	}
136	//【追加】排序的好方法
137	dt.DefaultView.Sort = "ID ,Name ASC";
138	dt=dt.DefaultView.ToTable();