Question

今天我正在处理如何将字节数组保存到SQLite数据库的问题。当我将base []保存到数据库时，它看起来像持有该数组的属性，但实际上它不保存到数据库，当我在设备上重新启动应用程序时。也许我必须在将byte []转换为base 64之前将其转换为数据库？如果是的话，我怎么能这样做？也许还有另一种方法保存到sqlite数据库，而不转换为base64？

这是我的对象类：

public class Unit
    {
        [PrimaryKey, AutoIncrement]
        public int Id { get; set; }
        public bool IsStarted { get; set; }
        public byte[] CImage { get; set; }
    }

这里我从图库中选择图片并设置为可绑定值：

IGalleryImageService galleryService = Xamarin.Forms.DependencyService.Get<IGalleryImageService>();
            galleryService.ImageSelected += (o, imageSourceEventArgs) =>
            {
                ActiveP.CImageBindable = imageSourceEventArgs.ImageSource;

                MemoryStream st = new MemoryStream(imageSourceEventArgs.ImageSource);
                ImageSource imgSource = ImageSource.FromStream(() => st);
                (ActiveP.Page as PTemplate).CImage.Source = imgSource;
            };
            galleryService.SelectImage();

这是我正在更新数据库或将对象插入数据库的其他Unit类：

     private void UpdateObjectToDB()
     {
        PUnit pUinit = new PUnit()
        {
            Id = this.Id,
            IsStarted = this.IsStarted,
            CImage = this.CImage 
        };
        App.database.Update(pUinit);
    }

    public int InsertObjectToDB()
    {
        PUnit pUnit = new PUnit()
        {
            IsStarted = this.IsStarted,
            CCImage = this.CImage
        };
        return App.database.AddItem(pUnit);
}

我必须转换哪些内容以及如何实现？感谢您的回答或建议。

Answer 1

好吧，我通过将此类属性更改为字符串类型来解决问题：

public class Unit
    {
        [PrimaryKey, AutoIncrement]
        public string CImageBase64 { get; set; }
    }

然后在其他单元类中我更改了可绑定数据类型：

public string CImageBindable
        {
            get
            {
                return base.CImageBase64;
            }
            set
            {
                base.CImageBase64 = value;
                OnPropertyChanged(nameof(CImageBindable));
            }
        }

在这里我转换为64基地

    if (this.P.CImageBindable == null)
    {
        CImage.Source = "img.png";
    }
    else
    {
        var imageBytes = Convert.FromBase64String(this.P.CImageBindable);

        MemoryStream st = new MemoryStream(imageBytes);
        ImageSource imgSource = ImageSource.FromStream(() => st);
        CImage.Source = imgSource;
    }

图片选择也被转换：

IGalleryImageService galleryService = Xamarin.Forms.DependencyService.Get<IGalleryImageService>();
            galleryService.ImageSelected += (o, imageSourceEventArgs) =>
            {
                ActiveParking.CImageBindable = Convert.ToBase64String(imageSourceEventArgs.ImageSource);
                MemoryStream st = new MemoryStream(imageSourceEventArgs.ImageSource);
                ImageSource imgSource = ImageSource.FromStream(() => st);
                (ActiveParking.Page as PTemplate).CImage.Source = imgSource;
            };
            galleryService.SelectImage();

Answer 2

你可以试试这个

     private void UpdateObjectToDB()
     {
        PUnit pUinit = new PUnit()
        {
            Id = this.Id,
            IsStarted = this.IsStarted,
            CImage = Encoding.ASCII.GetBytes(this.CImage) 
        };
        App.database.Update(pUinit);
    }

    public int InsertObjectToDB()
    {
        PUnit pUnit = new PUnit()
        {
            IsStarted = this.IsStarted,
            CCImage = Encoding.ASCII.GetBytes(this.CImage)
        };
        return App.database.AddItem(pUnit);
}

Xamarin表单，如何将byte []保存到SQLite数据库？

2 个答案: