Datatable learning

 

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Text;
  4 using System.Data;
  5 
  6 namespace DatatablesColumnsRows
  7 {
  8     class Program
  9     {
 10         static void Main(string[] args)
 11         {
 12             DataTable dt = new DataTable();
 13 
 14             //code format 01
 15             DataColumn dc01 = new DataColumn("StrVal", typeof(string));
 16             dt.Columns.Add(dc01);
 17 
 18             //code format 02
 19             DataColumn dc02 = new DataColumn();
 20             dc02.ColumnName = "IntVal";
 21             dc02.DataType = typeof(int);
 22             dt.Columns.Add(dc02);
 23 
 24             DataColumn dc03 = new DataColumn();
 25             dc03.DataType = System.Type.GetType("System.Decimal");
 26             dc03.AllowDBNull = false;
 27             dc03.Caption = "DclVal";
 28             dc03.ColumnName = "DclVal";
 29             dc03.DefaultValue = 1;
 30             dt.Columns.Add(dc03);
 31 
 32             //code format 03
 33             dt.Columns.Add("ObjVal");
 34 
 35             //code format 04
 36             dt.Columns.Add("DTimeVal", typeof(DateTime));
 37 
 38             //code format new row.
 39             DataRow dr = dt.NewRow();
 40             dr["StrVal"] = "AAA";
 41             dr["DclVal"] = -123456789.0123;
 42             dr["IntVal"] = 123;
 43             dr["ObjVal"] = 123.456;
 44             dr["DTimeVal"] = DateTime.Now;
 45             dt.Rows.Add(dr);
 46 
 47             DataRow r;
 48             for (int i = 0; i < 10; i++)
 49             {
 50                 r = dt.NewRow();
 51                 r["IntVal"] = i + 1;
 52 
 53                 // Be sure to add the new row to the 
 54                 // DataRowCollection. 
 55                 dt.Rows.Add(r);
 56             }
 57 
 58             Console.WriteLine("---------show value by rows-----------------");
 59             foreach (DataRow row in dt.Rows)
 60             {
 61                 foreach (DataColumn column in dt.Columns)
 62                 {
 63                     Console.WriteLine(row[column]);
 64                 }
 65             }
 66 
 67             Console.WriteLine("---------show value by row count-----------------");
 68             for (int i = 0; i < dt.Rows.Count; i++)
 69             {
 70                 Console.WriteLine(dt.Columns[0].ToString() + " - " + dt.Rows[i]["StrVal"].ToString());
 71                 Console.WriteLine(dt.Columns[1].ToString() + " - " + dt.Rows[i]["IntVal"].ToString());
 72                 Console.WriteLine(dt.Columns[2].ToString() + " - " + dt.Rows[i]["DclVal"].ToString());
 73                 Console.WriteLine(dt.Columns[3].ToString() + " - " + dt.Rows[i]["ObjVal"].ToString());
 74                 Console.WriteLine(dt.Columns[4].ToString() + " - " + dt.Rows[i]["DTimeVal"].ToString());
 75             }
 76 
 77             Console.WriteLine("---------show value by DataColumnCollection------");
 78             DataColumnCollection clms = dt.Columns;
 79             foreach (DataColumn column in clms)
 80             {
 81                 Console.WriteLine("Column Name: " + column.ColumnName);
 82                 Console.WriteLine("Column Type: " + column.DataType);
 83             }
 84 
 85             Console.WriteLine("---------copy table------");
 86             DataTable dtCopy = dt.Copy();
 87             foreach (DataRow tempDr in dtCopy.Rows)
 88             {
 89                 Console.WriteLine(tempDr[0].ToString());
 90                 Console.WriteLine(tempDr[1].ToString());
 91                 Console.WriteLine(tempDr[2].ToString());
 92                 Console.WriteLine(tempDr[3].ToString());
 93                 Console.WriteLine(tempDr[4].ToString());
 94             }
 95 
 96 
 97             Console.WriteLine("---------clone table------");
 98             DataTable dtClone = dt.Clone();
 99             foreach (DataRow tmpDr in dtClone.Rows)
100             {
101                 Console.WriteLine(tmpDr[0].ToString());
102                 Console.WriteLine(tmpDr[1].ToString());
103                 Console.WriteLine(tmpDr[2].ToString());
104                 Console.WriteLine(tmpDr[3].ToString());
105                 Console.WriteLine(tmpDr[4].ToString());
106             }
107             DataColumnCollection clms2 = dtClone.Columns;
108             foreach (DataColumn column2 in clms2)
109             {
110                 Console.WriteLine("Column Name: " + column2.ColumnName);
111                 Console.WriteLine("Column Type: " + column2.DataType);
112             }
113 
114 
115             DataRow row2;
116             int RowCount = dtClone.Rows.Count;
117             int ColCount = dtClone.Rows.Count;
118             for (int rowIndex = 1; rowIndex <= RowCount; rowIndex++)
119             {
120                 row2 = dtClone.NewRow();
121                 for (int i = 1; i <= ColCount; i++)
122                 {
123                     row2["ColString" + i.ToString()] = string.Concat(rowIndex.ToString(), ".", i.ToString());
124                     row2["ColInt" + i.ToString()] = rowIndex * 1000 + i;
125                 }
126                 dtClone.Rows.Add(row2);
127             }
128 
129             foreach (DataRow tmpDr in dtClone.Rows)
130             {
131                 Console.WriteLine(tmpDr[0].ToString());
132                 Console.WriteLine(tmpDr[1].ToString());
133                 Console.WriteLine(tmpDr[2].ToString());
134                 Console.WriteLine(tmpDr[3].ToString());
135                 Console.WriteLine(tmpDr[4].ToString());
136             }
137 
138             Console.ReadLine();
139 
140         }
141     }
142 }