如何使用ASP.NET MVC在数据库中存储多个选中的Checkbox值

Question

I am developing a project using ASP MVC and stored procedures (SQL Server), I want to store checked checkbox items in database. I've tried to add a List<string> type in model in order to access these value and then store them in the database.

The problem that the relational databases are designed specifically to store one value per row/column combination. In order to store more than one value, I must serialize my list into a single value for storage, then deserialize it upon retrieval.

That's my view markup:

               <h6>Items</h6>
                    <ul>
                        <li>
                            <label class="anim">
                                <input type="checkbox" class="checkbox" value="Soups" name="Items">
                                <span>Soups</span>
                            </label>
                        </li>
                        <li>
                            <label class="anim">
                                <input type="checkbox" class="checkbox" value="Burger" name="Items" >
                                <span>Burger</span>
                            </label>
                        </li>
                        <li>
                            <label class="anim">
                                <input type="checkbox" class="checkbox" value="Drinks" name="Items">
                                <span>Drinks</span>
                            </label>
                        </li>
                        <li>
                            <label class="anim">
                                <input type="checkbox" class="checkbox" value="Desserts" name="Items">
                                <span>Desserts</span>
                            </label>
                        </li>
                    </ul>

Method AddBestellung :

try
{
    using (SqlConnection con = new SqlConnection(Connection()))
    {
        using (SqlCommand cmd = new SqlCommand("AddNewBestellung", con))
        {
            foreach(var item in bs.Items)
            {
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.AddWithValue("@Items", item);
            }

            // Another saved parameters...

            con.Open();
            int i = cmd.ExecuteNonQuery();
            con.Close();

            if (i >= 1)
                return true;
            else
                return false;
        }
    }
}
catch(Exception ex)
{
    string e = ex.Message;
    return false;
}

private static string Connection()
{
    return ConfigurationManager.ConnectionStrings["deliverycon"].ToString();
}

Model:

public List<string> Items { get; set; }

Answer 1

You shouldn't serialize/deserialize. This will be painful to use afterward.

Imagine you need to retrieve objects that have items 1 and 5 checked. If it's serialized as a string it's less efficient and easy that to store it as follow.

Let's say you have a "Person" table and you want to check the list of "Consoles" they own.

You'll have table person :

• id int primary key
• Name varchar not null

and the table console

• id int primary_key
• name varchar not null

and the table to store the console owned :

owned_console

• id int primary key
• person_id int (foreign key => person(id))
• console_id int (foreign key => console(id))

In your code, you will insert a record per checkbox checked.

Person:

• (1)Thomas
• (2)Pierre

Console:

• (1)NES
• (2)MegaDrive
• (3)NeoGeo

owned_console:

• (1)(1)
• (1)(2)

• (1)(3)

• (2)(1)

• (2)(1)

And then you can do things like :

SELECT * 
FROM   person p
INNER  JOIN owned_console oc
ON     p.id = oc.person_id
WHERE  oc.console_id IN (3,1);

Answer 2

Flags Enumeration -

[Flags]
public enum ItemStorage
{
    Soups = 1,
    Burger = 2,
    Drinks = 4,
    Dessert = 8,
    Cheese = 16
}

I added the Cheese just to emphasise the binary nature of the Flags enum.

And here's your other code -

public class Stuff
{
    private List<string> Items;
    private static string Connection()
    {
        return ConfigurationManager.ConnectionStrings["deliverycon"].ToString();
    }

    public bool DoStuff()
    {
        try
        {
            using (SqlConnection con = new SqlConnection(Connection()))
            {
                using (SqlCommand cmd = new SqlCommand("AddNewBestellung", con))
                {

                    cmd.Parameters.AddWithValue("@Items", (int)ConstuctEnumValueFromList(Items));
                    //other saved parameters...

                    con.Open();
                    int i = cmd.ExecuteNonQuery();
                    con.Close();

                    if (i >= 1)
                        return true;
                    else
                        return false;
                }
            }
        }
        catch (Exception ex)
        {
            string e = ex.Message;
            return false;
        }
    }

    private ItemStorage ConstuctEnumValueFromList(List<string> list)
    {
        var result = new ItemStorage();
        if (list.Any())
        {
            var separatedList = string.join(",", list)
            bool success = Enum.TryParse<ItemStorage>(separatedList, out result)
        }
        return result;
    }
}

In this case, you can simply store the Items field as a single integer and cast it back to ItemStorage when retrieving like so -

int i = 1 + 2 + 4 + 8;
var items = (ItemStorage)i;
Console.WriteLine(items.ToString());

This should give you "Soups, Burger, Drinks, Desserts";

Answer 3

XML Serialization

First, make sure you're familiar with this document . This method requires that you store your Items collection to an XML column in SQL Server. It also has the advantage that you can query against that column, provided you're not afraid of SQLXML and XPath. Many developers are.

Once you have that, everything looks very similar (if a little simpler).

public class Stuff
{
    private List<string> Items;
    private static string Connection()
    {
        return ConfigurationManager.ConnectionStrings["deliverycon"].ToString();
    }

    public bool DoStuff()
    {
        try
        {
            using (SqlConnection con = new SqlConnection(Connection()))
            {
                using (SqlCommand cmd = new SqlCommand("AddNewBestellung", con))
                {

                    cmd.Parameters.AddWithValue("@Items", ConstructXmlFromList(Items));
                    //other saved parameters...

                    con.Open();
                    int i = cmd.ExecuteNonQuery();
                    con.Close();

                    if (i >= 1)
                        return true;
                    else
                        return false;
                }
            }
        }
        catch (Exception ex)
        {
            string e = ex.Message;
            return false;
        }
    }

    public static T FromXML<T>(string xml)
    {
        using (var stringReader = new StringReader(xml))
        {
            var serializer = new XmlSerializer(typeof(T));
            return (T)serializer.Deserialize(stringReader);
        }
    }

    public string ToXML<T>(T obj)
    {
        using (var stringWriter = new StringWriter(new StringBuilder()))
        {
            var xmlSerializer = new XmlSerializer(typeof(T));
            xmlSerializer.Serialize(stringWriter, obj);
            return stringWriter.ToString();
        }
    }

    private string ConstructXmlFromList(List<string> list)
    {
        return ToXML(list);
    }
}

And again, it's easy to rehydrate the XML fragment into the List<string> that you started with. You'd simply use

var myList = FromXML<List<string>>(fieldValue);