Creating a DataColumn and Adding It to a DataTable : DataTable « ADO.Net « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. ADO.Net
3. DataTable

using System;
using System.Data;

    class Program
    {
        static void Main(string[] args)
        {
            DataTable dt = new DataTable();

            DataColumn col1 = dt.Columns.Add();
            col1.ColumnName= "First Column";
            col1.DataType = typeof(int);
            col1.DefaultValue = 0;
            col1.Unique = true;
            col1.AllowDBNull = false;

            DataColumn col2 = new DataColumn();
            col2.ColumnName = "Second Column";
            col2.DataType = typeof(string);
            col2.MaxLength = 50;
            dt.Columns.Add(col2);

            dt.Columns.Add("Column-3", typeof(string)).MaxLength = 50;

            DataColumn col4 = new DataColumn("Column-4");
            DataColumn col5 = new DataColumn("Column-5", typeof(int));
            dt.Columns.AddRange(new DataColumn[] { col4, col5 });

            Console.WriteLine("DataTable has {0} DataColumns named:",dt.Columns.Count);
            foreach (DataColumn col in dt.Columns)
                Console.WriteLine("\t{0}", col.ColumnName);
        }
    }