在更新查询期间，它抛出NotSupportedException

我正在处理windows存储应用程序中的SQLite。我正在使用更新表中的值

var tagPage = db.QueryAsync<MyModel>("UPDATE MyModel SET Tag =2 WHERE id = 1");
db.UpdateAsync(tagPage);

它通过方法在SQLite.cs类上抛出NotSupportedException

public int Update(object obj, Type objType)
{
    if (obj == null || objType == null)
        {
            return 0;
        }
        var map = GetMapping(objType);
        var pk = map.PK;
        if (pk == null)
        {
            throw new NotSupportedException("Cannot update " + map.TableName + ": it has no PK");
        }
        var cols = from p in map.Columns
                   where p != pk
                   select p;
        var vals = from c in cols
                   select c.GetValue(obj);
        var ps = new List<object>(vals);
        ps.Add(pk.GetValue(obj));
        var q = string.Format("update '"{0}'" set {1} where {2} = ? ", map.TableName, string.Join(",", (from c in cols
                                                                                                        select "'"" + c.Name + "'" = ? ").ToArray()), pk.Name);
        return Execute(q, ps.ToArray());
}

因为我认为它不会得到素数，我在表中提供了素数。我尝试了异步和等待，但没有用，为什么会发生这种情况？请帮我

public class MyModel
{
    [PrimaryKey, AutoIncrement]
    public int Id { get; set; }
    public int Tag { get; set; }        
    public string Foo { get; set; }
}