ISaveContext Interface

.NET Standard 2.x

Represents the save context when saving the data changes to the database.

It provides a series of methods for reading or manipulating the save context.

Namespace: SnapObjects.Data

Assembly: SnapObjects.Data.dll

Syntax

  public interface ISaveContext;

Properties

Name	Returns Type	Description
Count	int	Gets the number of the added values in the context of saving the data.
LastDbResult	IDbResult	Gets the result of the most recent operation that uses the model to save data to the database.
Names	IReadOnlyList<string>	Gets the name of all of the added values.

Method

Name	Returns Type	Description
Add(string name, object value)	void	Adds a value of any data type and its name to the save context.
CancelSave()	void	Cancels the operation that is currently being executed to save the data to the database.
Contains(string name)	bool	Returns whether the save context contains the specified value.
Get(string name)	object	Gets the specified value from the save context.
Remove(string name)	void	Removes the specified value from the save context.
RemoveAll()	void	Removes all of the added values from the save context.

Examples

The following code example demonstrates how to use ISaveContext to read and manipulate the save context when saving the student.

using Appeon.ApiDoc.Models.School;
using System;

namespace Appeon.ApiDoc.ISaveContextExamples
{
    public class ISaveContextExample
    {
        private SchoolContext _context;

        public ISaveContextExample(SchoolContext dataContext)
        {
            // Sets the data context.
            _context = dataContext;
        }

        public void Example()
        {
            var mapper = _context.SqlModelMapper;

            // Sets the properties for the new student.
            var newStudent = new Person()
            {
                LastName = "Senior",
                FirstName = "Letitia",
                EnrollmentDate = new DateTime(2019, 1, 1),
                Discriminator = "Student"
            };

            // Tracks the Insert operation for the new student.
            mapper.TrackCreate(newStudent);

            // Adds names to Save Context in an Action.
            mapper.Track((saveContext) =>
            {
                // Adds a value to Save Context.
                saveContext.Add("newPersonID", newStudent.PersonID);

                // Gets the last database result from Save Context.
                var lastResult = saveContext.LastDbResult;
                saveContext.Add("Affected", lastResult.AffectedCount);

                // Shows how many names were added in Save Context.
                Console.WriteLine("{0} Names:",
                    saveContext.Count);

                // Lists the names added in Save Context.
                foreach (string name in saveContext.Names)
                {
                    Console.WriteLine(name);
                }
            });

            // Reads and removes names in another Action.
            mapper.Track((saveContext) =>
            {
                // Checks if it contains a name.
                Console.WriteLine("Check if it contains 'newPersonID': {0}",
                    saveContext.Contains("newPersonID"));

                // Gets the value.
                int newID = (int)saveContext.Get("newPersonID");
                Console.WriteLine("The Person ID generated by the database is {0}.",
                    newID);

                // Removes a name.
                saveContext.Remove("newPersonID");

                // Removes all names.
                saveContext.RemoveAll();

                // Cancels the save operation and roll back the database transaction.
                saveContext.CancelSave();
            });

            var dbResult = mapper.SaveChanges();

            Console.WriteLine("Check if the SaveChanges method was cancelled: {0}",
               dbResult.Cancelled);

            /* The code produces the following output:
            
            2 Names:
            newPersonID
            Affected
            Check if it contains 'newPersonID': True
            The Person ID generated by the database is 75.
            Check if the SaveChanges method was cancelled: True
            */
        }
    }
}

Example Refer To

Model Class: Student