的EntityFramework通過ID

Question

過濾列表，我有這樣的功能：

[HttpPost] 
[Route("")] 
/// <summary> 
/// Create a team 
/// </summary> 
/// <param name="model">The team model</param> 
/// <returns>The modified team model</returns> 
public async Task<IHttpActionResult> Create(TeamBindingViewModel model) 
{ 

    // If our model is invalid, return the errors 
    if (!ModelState.IsValid) 
     return BadRequest(ModelState); 

    // Get all our colours 
    var colours = await this.colourService.GetAllAsync(); 

    // Create our new model 
    var team = new Team() 
    { 
     Name = model.Name, 
     Sport = model.Sport 
    }; 

    // For each colour, Add to our team 
    team.Colours = colours.Join(model.Colours, c => c.Id, m => m.Id, (c, m) => new Colour { Id = c.Id, Hex = c.Hex, Name = c.Name }).ToList(); 

    // Create our team 
    this.service.Create(team); 

    // Save our changes 
    await this.unitOfWork.SaveChangesAsync(); 

    // Assign our Id to our model 
    model.Id = team.Id; 

    // Return Ok 
    return Ok(model); 
} 

如果我運行它，然後進入的EntityFramework新的顏色到數據庫中，而不是引用的顏色。 我知道這是因爲我在我的連接中創建了一個新顏色。 如果我改變我的功能是：

[HttpPost] 
[Route("")] 
/// <summary> 
/// Create a team 
/// </summary> 
/// <param name="model">The team model</param> 
/// <returns>The modified team model</returns> 
public async Task<IHttpActionResult> Create(TeamBindingViewModel model) 
{ 

    // If our model is invalid, return the errors 
    if (!ModelState.IsValid) 
     return BadRequest(ModelState); 

    // Get all our colours 
    var colours = await this.colourService.GetAllAsync(); 

    // Create our new model 
    var team = new Team() 
    { 
     Name = model.Name, 
     Sport = model.Sport 
    }; 

    // For each colour, Add to our team 
    team.Colours = colours; 

    // Create our team 
    this.service.Create(team); 

    // Save our changes 
    await this.unitOfWork.SaveChangesAsync(); 

    // Assign our Id to our model 
    model.Id = team.Id; 

    // Return Ok 
    return Ok(model); 
} 

，一切工作正常。 即在第二片段唯一改變的是：

team.Colours = colours.Join(model.Colours, c => c.Id, m => m.Id, (c, m) => new Colour { Id = c.Id, Hex = c.Hex, Name = c.Name }).ToList(); 

成爲

team.Colours = colours; 

這是從數據庫中檢索列表。 EntityFramework知道這並沒有改變，所以它只是引用顏色而不是創建新的。 如何讓我的過濾列表執行相同的操作？

乾杯， /r3plica

Answer 1

好吧，我知道這很簡單。 我改變了這個問題行：

// For each colour, Add to our team 
team.Colours = colours.Where(m => model.Colours.Any(c => c.Id == m.Id)).ToList();