「EntityType沒有定義密鑰」，但我加了[Key]，爲什麼？

Question

我有這樣一個模型類：

public class Task 
{ 
    [Key] 
    public int TaskId; 

    public string TaskDescription; 
    public DateTime StartTime; 
    public DateTime FinishTime; 
    public bool isActive; 
} 

和下表中的數據庫：

CREATE TABLE [dbo].[Tasks] 
(
    [TaskId] INT NOT NULL PRIMARY KEY IDENTITY, 
    [TaskDescription] NVARCHAR(max) NOT NULL, 
    [StartTime] DATE NOT NULL, 
    [FinishTime] DATE NOT NULL, 
    [isActive] BIT NOT NULL DEFAULT 1 
) 

編譯後，我得到這個錯誤：

An exception of type 'System.Data.Entity.ModelConfiguration.ModelValidationException' occurred in EntityFramework.dll but was not handled in user code

Additional information:

One or more validation errors were detected during model generation:

Planner.Domain.Concrete.Task: : EntityType 'Task' has no key defined. Define the key for this EntityType. Tasks: EntityType: EntitySet 'Tasks' is based on type 'Task' that has no keys defined.

如何解決一？

Answer 1

請添加get和set訪問器。像這樣。

[Key] 
    public int TaskId {get; set;} 
    public string TaskDescription {get; set;} 
    public DateTime StartTime {get; set;} 
    public DateTime FinishTime {get; set;} 
    public bool isActive {get; set;}