Description, methods, and sample locks

It should be noted that the locking mechanism is implemented service locks LockService that stores information about the selected data object to the lock in the data store. This is to protect against changes in the data object, even if it is being edited by another user.

However, there are situations when it is convenient temporarily to protect any data object from being modified, for example, from the change in error from any other place in the program. In this case, instead of using the service of locks, you can apply described in this article method.

When using the described method, information on lock is stored directly in the instance of data object: lock setting will not affect other instances of the object.

Usage example: in a Windows application lock is set in this manner for the data object, if it opens the edit form and the user does not have authority to modify the object.

blocking Methods in the DataObject

To lock you need to call the data object method DataObject#LockObject with any key block (any value of any type).

Unblock can call the method DataObject#LockObject passing the same key. Thus, to unlock the object only knowing the key lock that prevents accidental changes to the object data.

All the time while the object is locked, the property IsReadOnly returns true and protected (protected) method of the data object throws an exception CheckReadOnly DataObjectIsReadOnlyException. Accordingly, checking for blockages, the programmer must either hold «outside» data object with a call to IsReadOnly properties, or add properties inside of the data object before changing values in the method call CheckReadOnly. You should not abuse this opportunity (add CheckReadOnly in many places), as this will cause a performance drop when accessing the properties - it is better to explicitly check IsReadOnly.

Example

using System;
using ICSSoft.STORMNET;

namespace Locking
{
	public class MyDataObject:DataObject
	{
		private string fMyAttr;

		public virtual string MyAttr
		{
			get
			{
				return fMyAttr;
			}
			set
			{
				fMyAttr=value;
			}
		}
	}

	public class MyOverridedDataObject:MyDataObject
	{
		public override string MyAttr
		{
			set
			{
				CheckReadOnly();
				base.MyAttr = value;
			}
		}

	}

	class Class1
	{

		private static MyDataObject my = new MyDataObject();
		private static  MyOverridedDataObject myover = new MyOverridedDataObject();

		private static void prv_PrintObjects()
		{
			Console.WriteLine("my.MyAttr={0}, myover.MyAttr={1}", my.MyAttr, myover.MyAttr);
		}

		[STAThread)
		static void Main(string[) args)
		{
			my.MyAttr = "STORM.NET";
			myover.MyAttr = "STORM.NET";

			prv_PrintObjects();

			my.LockObject(1);
			myover.LockObject(2);
			//Necessary for my clear test 
			if (my.IsReadOnly) 
			{
				Console.WriteLine("my Locked");
			}
			else
			{
				my.MyAttr = "STORM.NET Framework";
			}

			//For myover - no 
			try
			{
				myover.MyAttr= "STORM.NET Framework";
			}
			catch (Exception exc)
			{
				Console.WriteLine(exc.Message);
			}

			prv_PrintObjects();

			my.UnLockObject(1);
			myover.UnLockObject(2);

			my.MyAttr = "STORM.NET Framework";
			myover.MyAttr= "STORM.NET Framework";

			prv_PrintObjects();

			Console.WriteLine("\n\n\press Enter to exit.");
			Console.Read();
		}
	}
}
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