实体框架：如何在一列中使用两个记录

Question

I'm creating a simply database with Entity Framework using ASP.NET, i have class "Graphics" and class "InputOutput". I want to set in Initializer two records from InputOutput to Graphics one column.

Graphics.cs

public class Graphics
    {
        public int GraphicsID { get; set; }
        public int ProducerID { get; set; }
        public int InputOutputID { get; set; }

        public string Name { get; set; }
        public string TypeOfConnection { get; set; }
        public string ProducerOfChipset { get; set; }
        public string TypOfMemory { get; set; }
        public string CoreSpeed { get; set; }
        public string MemoryClock { get; set; }
        public string MultiCardsTech { get; set; }
        public string HDCP { get; set; }
        public string CUDA { get; set; }
        public string VRReady { get; set; }
        public string TypeOfCooling { get; set; }

        public string Size { get; set; }

        public ICollection<InputOutput> InputOutput { get; set; }
        public ICollection<Producer> Producer { get; set; }
        public ICollection<LaptopProduct> LaptopProduct { get; set; }

    }

InputOutput.cs

public class InputOutput
    {
        public int InputOutputID { get; set; }
        public string Name { get; set; }

        public ICollection<Graphics> Graphics { get; set; }
    }

And from Initializer:

var inputoutputs = new List<InputOutput>
            {
                new InputOutput { Name = "DVI"},
                new InputOutput { Name = "HDMI"},
                new InputOutput { Name = "VGA"}
            };

var graphics = new List<Graphics>
            {
                new Graphics { Name="GTX 1080", ProducerID=4, InputOutputID = "HERE ? What should i write to set 2 properties?" },
                new Graphics { Name="GTX 1070", ProducerID=4},
                new Graphics { Name="GTX 1080Ti", ProducerID=4},
            };

I want to display GTX1080 with eg two ports HDMI and VGA but i can only set one property to InputOutputID.

Answer 1

In your initializer you can reference your previous list inputoutputs .

var graphics = new List<Graphics>
            {
                new Graphics { Name="GTX 1080", ProducerID=4, InputOutputID = inputoutput[0].InputOutputId, InputOutput = 
                   new List<InputOutput> { 
                           inputoutputs[0], inputoutputs[1] 
                   },
                new Graphics { Name="GTX 1070", ProducerID=4},
                new Graphics { Name="GTX 1080Ti", ProducerID=4},
            };

However, since this is a many to many, I'm not sure how the InputOutputID column is going to be used. You need the junction table to get the items you need.

Here's an example of many to many in EF. http://www.entityframeworktutorial.net/code-first/configure-many-to-many-relationship-in-code-first.aspx

Note, each table only have the collection to each other and none of the other table's ID attributes.

I also subscribe to making my many to many tables explicit in my ORM mappings. AKA - I actually create the junction table in EF code. Jimmy Bogard has a great example and reasons for this.