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new with delegates and lambda expressions [closed]

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Basically I want to create a method that can return a string message regarding on what currently happening inside a method
example:
public MainMethod()
{
//Execute One
//Execute Two
//Execute Three
}
upon using it I'm thinking of like this
something = delegate (string message) {console.writeline("{0}",message)};
the output would be
Execute One
Execute Two
Execute Three
Is this possible using delegate or lambda? if yes can I ask for an example on how I should correctly implement this? if no please help me with alternative.
Thanks

Use Func and Action. They make interacting with delegates much easier. Funcs have return values, Actions do not:
public MainMethod()
{
Action<string> writerAction = (message) => Console.WriteLine(message);
writerAction("Execute One");
writerAction("Execute Two");
writerAction("Execute Three");
}

Check if any form fields have changed upon saving asp.net c# [closed]

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I've got a large .net form with hundreds of input fields, sometimes users navigate off the form page without saving, what's the best way to check if a field value has changed when they try to navigate away? some c# function or javascript?

Don't take the control out of the users hand :-)
Ask him on exit, if he wants to save the changes. Maybe he did some changes by mistake, which you don't want to save.
You can achieve this by Javascript/Jquery. Something like:
$(document).ready(function() {
formmodified=0;
$('form *').change(function(){
formmodified=1;
});
window.onbeforeunload = confirmExit;
function confirmExit() {
if (formmodified == 1) {
return "New information not saved. Do you wish to leave the page?";
}
}
$("input[name='commit']").click(function() {
formmodified = 0;
});
});

C# How to pause program [closed]

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I have simple question. How do I pause program? I want to change pictures very slowly.
My code:
private void button2_Click(object sender, EventArgs e){
Image picture1 = Program.Properties.Resources.picture1;
Image picture2 = Program.Properties.Resources.picture2;
Button1.Image = picture1
//Here I want pause
Button1.Image = picture2
}

If you want procedural code (like in your example), without timers and without locking the UI:
await Task.Delay(1000)

You can use Threads or Timers.
http://msdn.microsoft.com/en-us/library/swx5easy.aspx
http://programmingbaba.com/how-to-stop-system-threading-timer-in-c-do-net/
Or you can use Sleep method to puase your program.
http://www.dotnetperls.com/sleep

What's desirable about callback functions when you can make a regular function call? [closed]

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I'm new to programming and I've noticed that callback functions are passed in as parameters to other functions
Otherfunction(argument,callbackfunction(code...code))
This seems cumbersome no? Why not just do the following:
Otherfunction(argument)
{
callbackfunction();
}
Callbackfunction()
{
//callback function is defined here.
}
Why inundate the parameter list of a function with a callback?

If you don't pass in the callback function, then the called function needs to know which function to call. This severely limits its reuse. Passing in a callback function also allows you to modify its behavior.
Consider the following:
void DoSomethingAndNotify(Action<string> notifyCallback)
{
// Do something
...
string result = "something was done";
notifyCallback(result);
}
void EmailNotifier(string message)
{
// Send message via email
}
void ConsoleNotifier(string message)
{
Console.WriteLine(message);
}
Then you can "do something" with different types of notifications, and you can add new notification types without ever having to change DoSomethingAndNotify().

Best way to do a multithread foreach loop [closed]

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I have a send email method with a foreach, like this:
static void Main(string[] args)
{
foreach(var user in GetAllUsers())
{
SendMail(user.Email);
}
}
I need to improve that method. Using a multithread, because i dont want to wait the SendMail method executes each time for each user.
Any sugestions to do that?
Thanks

Try using a parallel foreach. I.e.
Parallel.ForEach(GetAllUsers(), user=>
{
SendMail(user.Email);
});

You can try something like this
private void Send()
{
Parallel.Foreach(GetAllUsers(), user =>
{
SendMail(user.Email);
});
}

I think the easiest way to do this would be thread pooling. .Net makes this pretty easy and you can read more about it here.