将新字段离子添加到我的绑定对象时，DbContext 因 InvalidOperationException 而失败

Question

所以这是我的 binding 类型：

public class ClipboardItem : INotifyPropertyChanged
    {        
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        private int id { get; set; }
        private string text;
        private string name;        
        private string processName;
        private string time;

        public ClipboardItem(int id, string text, string name, string processName, string time, bool isPinned)
        {
            this.id = id;
            this.text = text;
            this.name = "";          
            this.processName = processName;
            this.time = time;
        }
}

DbContext

public class ClipboardItemContext : DbContext
    {
        public DbSet<ClipboardItem> Clipboards { get; set; }
        public string DbPath { get; }

        public ClipboardItemContext()
        {
            var folder = Environment.SpecialFolder.LocalApplicationData;
            var path = Environment.GetFolderPath(folder);
            DbPath = System.IO.Path.Join(path, "clipboards.db"); 
            Database.EnsureCreated();
        }

        // The following configures EF to create a Sqlite database file in the
        // special "local" folder for your platform.
        protected override void OnConfiguring(DbContextOptionsBuilder options) => options.UseSqlite($"Data Source={DbPath}");

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {

            modelBuilder.Entity<ClipboardItem>().HasKey(p => new { p.Id });
        }
    }

所以这很好用，我可以 add、read、update 和 delete 我的 DB.

项目

现在我想在 binding type 中添加新字段：

private bool isPinned;

我的Ctor

public ClipboardItem(int id, string text, string name, string processName, string time, bool isPinned)
        {
            this.id = id;
            this.text = text;
            this.name = "";          
            this.processName = processName;
            this.time = time;
            this.isPinned= isPinned;
            Properties.Settings.Default.ItemIndex++;
        }

在再次运行我的应用程序之前，我删除了我的 .db 文件，因为这个新字段，当我尝试启动我的应用程序时，我得到了这个 exception:

System.InvalidOperationException: 'No suitable constructor was found for entity type 'ClipboardItem'. The following constructors had parameters that could not be bound to properties of the entity type: cannot bind 'isPinned' in 'ClipboardItem(int id, string text, string name, string processName, string time, bool isPinned)'.'

我的 DB 似乎不接受这个新字段，我也尝试添加不同的 type 例如 int 或 string 但我还是一样错误。

当我删除这个新字段时，我的 .db 创建了我的 application 运行ning.

Answer 1

Sqlite does not have a separate Boolean storage class. Instead, Boolean values are stored as integers 0 (false) and 1 (true)

只需将您的字段映射为整数，

[Column(TypeName = "INTEGER")]
public bool isPinned;

或者你可以用OnModelCreating来做，

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
     modelBuilder.Entity<ClipboardItem>().HasKey(p => new { p.Id });
     modelBuilder.Entity<ClipboardItem>().Property(p => p.isPinned)    
                                            .HasConversion(x => x ? 1 : 0,       
                                                           x => (x == 1));
}

将新字段离子添加到我的绑定对象时，DbContext 因 InvalidOperationException 而失败

DbContext failed with InvalidOperationException when add new field ionto my binding object

c#

dbcontext