Question

我在数据库中有想要异步加载到图片框中的图像。我该怎么做？现在我有：

byte[] byteBLOBData = new byte[0];
byteBLOBData = (byte[])ds.Tables["magazine_images"].Rows[c - 1]["image"];
MemoryStream stmBLOBData = new MemoryStream(byteBLOBData);
pictureBox1.Image = Image.FromStream(stmBLOBData);
pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;
labelMsg.Text = "Picture loaded successfully.";

我想做：

pictureBox1.LoadAsync("What should I put here?");

我正在使用MySQL数据库和Visual Studio 2010 C＃

Answer 1

不要将字节加载到图像中，这会破坏您尝试实现的目的......（请注意，将图像转换为临时文件是一种快速的方法。这里有很多额外的考虑因素，当你完成时删除临时文件至少是这样的。

byte[] byteBLOBData = (byte[])ds.Tables["magazine_images"].Rows[c - 1]["image"];
string tempImageFileName = Path.Combine(Path.GetTempPath(), Path.GetTempFileName() + ".jpg");
using( FileStream fileStream = new FileStream(tempImageFileName, FileMode.OpenOrCreate, FileAccess.ReadWrite) ) {
    using( BinaryWriter writer = new BinaryWriter(fileStream) ) {
        writer.Write(byteBLOBData);
    }
}

pictureBox1.LoadCompleted += LoadCompleted;
pictureBox1.WaitOnLoad = false;
pictureBox1.LoadAsync(tempImageFileName);

...

private static void LoadCompleted( object sender, AsyncCompletedEventArgs e ) {
    if( e.Error != null ) {
        // will get this if there's an error loading the file
    } if( e.Cancelled ) {
        // would get this if you have code that calls pictureBox1.CancelAsync()
    } else {
        // picture was loaded successfully
    }
}

另见LoadProgressChanged事件

我想使用LoadAsync和MemoryStream将数据库中的图像加载到图片框中

1 个答案: