Power of lambda

Lambda is like sudo make me sandwich:  ^_^

string prefix = "tm";

this.GetAllControls().OfType<CheckBox>()
    .Where(cx => cx.Name.Substring(0, 2) == prefix)
    .ForEach(cx => cx.Visible = false); // do something here in ForEach

The above code reads as: prepare me a list of checkbox which starts with letters tm, and i'll do something on those checkboxes. You can concentrate on things you want to do.

I'll make it myself(without lambda):

string prefix = "tm";

foreach(Control cx in this.GetAllControls())
{
    if (cx is CheckBox && cx.Name.Substring(0, 2) == prefix)
    {
        // payload here, er.. do something here
        (cx as CheckBox).Visible = false; 
    }
    
    // who can be possibly sure that prefix wasn't altered here
    // prefix = "ax";
}

The above code reads as: i'm looking at all controls, check if control is checkbox and starts with letters tm, then i'll do something on that checkbox. And because it is loop, programmers tend to re-read the loop header's condition if all corner cases are covered.

Suppress Crystal Report Viewer's Main Report Tab

public static void SuppressReportTabs(
    this CrystalDecisions.Windows.Forms.CrystalReportViewer crv)
{
    foreach (System.Windows.Forms.Control control in crv.Controls)
        if (control is CrystalDecisions.Windows.Forms.PageView)
        {
            var tab = 
                (control as CrystalDecisions.Windows.Forms.PageView)
                .Controls[0] as System.Windows.Forms.TabControl;

            tab.ItemSize = new System.Drawing.Size(0, 1);
            tab.SizeMode = System.Windows.Forms.TabSizeMode.Fixed;
            tab.Appearance = System.Windows.Forms.TabAppearance.Buttons;
        }
} 

Updating a Data Source with a Dataset

my answer on stackoverflow question Updating a Data Source with a Dataset:

[WebMethod]
public bool SecureUpdateDataSet(DataSet delta)
{

     string connStr = WebConfigurationManager.ConnectionStrings["Employees"].ConnectionString;

     using(var conn = new SqlConnection(connStr))
     {
        conn.Open();

        string sql = "select * from tab1 where 1 = 0";

        var da = new SqlDataAdapter(sql, conn);

        var builder = new SqlCommandBuilder(ad);

        da.InsertCommand = builder.GetInsertCommand();
        da.UpdateCommand = builder.GetUpdateCommand();
        da.DeleteCommand = builder.GetDeleteCommand();

        da.Update(delta);

        return true;

    }
    return false;
}

Hello World

using System;
namespace Craft
{
    public class Mate
    {
        public static void Main() 
        {
            Console.WriteLine("Hello World!");
        }
    }
}