While I agree in general with Jon Skeet, there was an interesting presentation by Mads Torgensen demonstrating how async/await can be used to simplify such scenarios (using the techniques mentioned by Jon). After all, isn't that the same as with enumerators - we can write own enumerator class using state like index etc., but we almost never do that and use iterator blocks instead.
Anyway, here is the async/await technique we were talking about.
First, the reusable part:
public static class Utils
{
public static Task WhenClicked(this Button button)
{
var tcs = new TaskCompletionSource<object>();
EventHandler onClick = null;
onClick = (sender, e) =>
{
button.Click -= onClick;
tcs.TrySetResult(null);
};
button.Click += onClick;
return tcs.Task;
}
}
and your code using it (note that you need to mark your method as async)
foreach (string s in List)
{
txtName.Text = s;
await yourButton.WhenClicked();
}
Sample test putting it all together:
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace Samples
{
static class Test
{
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
var form = new Form();
var txtName = new TextBox { Parent = form, Top = 8, Left = 8 };
var buttonNext = new Button { Parent = form, Top = txtName.Bottom + 8, Left = 8, Text = "Next" };
form.Load += async (sender, e) =>
{
var List = new List<string> { "A", "B", "C", "D " };
foreach (string s in List)
{
txtName.Text = s;
await buttonNext.WhenClicked();
}
txtName.Text = "";
buttonNext.Enabled = false;
};
Application.Run(form);
}
}
public static class Utils
{
public static Task WhenClicked(this Button button)
{
var tcs = new TaskCompletionSource<object>();
EventHandler onClick = null;
onClick = (sender, e) =>
{
button.Click -= onClick;
tcs.TrySetResult(null);
};
button.Click += onClick;
return tcs.Task;
}
}
}
