Linq 学习

        DataTable dt=new DataTable();
        dt.Columns.Add("ID", typeof(int));
        dt.Columns.Add("Age", typeof(int));
        for (int i = 0; i < 10; i++)
        {
            DataRow dr = dt.NewRow();
            dr["ID"] = i + 1;
            dr["Age"] = DateTime.Now.ToString("fff");
            dt.Rows.Add(dr);
        }

        IEnumerable<DataRow> query1 = from contact in dt.AsEnumerable()
                                      where contact.Field<int>("ID") > 5
                                      select contact;

        DataTable contacts1 = query1.CopyToDataTable();

DataTable dtPosts = new DataTable();
using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["StackOverflow"].ConnectionString))
{
    conn.Open();
    using (SqlDataAdapter adapt = new SqlDataAdapter("SELECT TOP 100 Id, Title, Body, CreationDate FROM Posts WHERE Title IS NOT NULL ORDER BY Id", conn))
    {
        adapt.SelectCommand.CommandTimeout = 120;
        adapt.Fill(dtPosts);
    }
}

//use LINQ method syntax to pull the Title field from a DT into a string array...
string[] postSource = dtPosts
                    .AsEnumerable()
                    .Select<System.Data.DataRow, String>(x => x.Field<String>("Title"))
                    .ToArray();

var source = new AutoCompleteStringCollection();
source.AddRange(postSource);
textBox1.AutoCompleteCustomSource = source;
textBox1.AutoCompleteMode = AutoCompleteMode.SuggestAppend;
textBox1.AutoCompleteSource = AutoCompleteSource.CustomSource;