* Batch actions for visible books: 'remove from library' complete

* refactor entity properties into extension methods
* refactor shared simple message boxes => MessageBoxLib

Source/LibationWinForms/MessageBoxLib.cs

@@ -0,0 +1,72 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Windows.Forms;
+using DataLayer;
+using Dinah.Core.Logging;
+using LibationWinForms.Dialogs;
+using Serilog;
+
+namespace LibationWinForms
+{
+    public static class MessageBoxLib
+	{
+		/// <summary>
+		/// Logs error. Displays a message box dialog with specified text and caption.
+		/// </summary>
+		/// <param name="text">The text to display in the message box.</param>
+		/// <param name="caption">The text to display in the title bar of the message box.</param>
+		/// <param name="exception">Exception to log</param>
+		/// <returns>One of the System.Windows.Forms.DialogResult values.</returns>
+		public static DialogResult ShowAdminAlert(string text, string caption, Exception exception)
+		{
+			try
+			{
+				Serilog.Log.Logger.Error(exception, "Alert admin error: {@DebugText}", new { text, caption });
+			}
+			catch { }
+
+			using var form = new MessageBoxAlertAdminDialog(text, caption, exception);
+			return form.ShowDialog();
+		}
+
+		public static void VerboseLoggingWarning_ShowIfTrue()
+		{
+			// when turning on debug (and especially Verbose) to share logs, some privacy settings may not be obscured
+			if (Log.Logger.IsVerboseEnabled())
+				MessageBox.Show(@"
+Warning: verbose logging is enabled.
+
+This should be used for debugging only. It creates many
+more logs and debug files, neither of which are as
+strictly anonymous.
+
+When you are finished debugging, it's highly recommended
+to set your debug MinimumLevel to Information and restart
+Libation.
+".Trim(), "Verbose logging enabled", MessageBoxButtons.OK, MessageBoxIcon.Warning);
+		}
+
+		public static DialogResult ShowConfirmationDialog(IEnumerable<LibraryBook> libraryBooks, string format, string title)
+		{
+			if (libraryBooks is null || !libraryBooks.Any())
+				return DialogResult.Cancel;
+
+			var count = libraryBooks.Count();
+
+			string thisThese = count > 1 ? "these" : "this";
+			string bookBooks = count > 1 ? "books" : "book";
+			string titlesAgg = libraryBooks.AggregateTitles();
+
+			var message
+				= string.Format(format, $"{thisThese} {count} {bookBooks}")
+				+ $"\r\n\r\n{titlesAgg}";
+			return MessageBox.Show(
+				message,
+				title,
+				MessageBoxButtons.YesNo,
+				MessageBoxIcon.Question,
+				MessageBoxDefaultButton.Button1);
+		}
+	}
+}