在Web开发中,常见的做法如下:
将数据库中读取出来的内容以字节数组的形式存储,字符串型转字节数组的方法是Convert.FromBase64String,然后以二进制写的方法将图片信息写在页面中。主要代码如下:
SWDM dm = new SWDM(); protected void Page_Load(object sender, EventArgs e) { string strSQL = "select picContent from tb_ssxq where OBJECTID=1"; DataSet ds = dm.getsql(strSQL); byte[] byteFileStream = Convert.FromBase64String(ds.Tables[0].Rows[0]["picContent"].ToString()); Response.BinaryWrite(byteFileStream); Response.End(); }
在Silverlight中如何实现呢,其实差不多,只不过在WebService中的方法的返回值要是byte[]类型,然后在Silverlight中利用MemoryStream来接收并存储图片流信息,然后将其作为BitmapImage的Source即可,最后利用Silverlight的Image控件即可显示出该图片。
WebService中的代码如下:
/// <summary> /// 根据险情ID获取实时险情的图片信息 /// </summary> /// <param name="paramCity"></param> /// <returns></returns> [WebMethod(Description = "获取某一个实时险情的图片信息")] public byte[] getSSXPictureQByID(string xqid) { byte[] byteFileStream = null; string strSQL = "select picContent from tb_ssxq where OBJECTID=" + int.Parse(xqid); DataSet ds = dm2.getsql(strSQL); byteFileStream = Convert.FromBase64String(ds.Tables[0].Rows[0]["picContent"].ToString()); return byteFileStream; }
Silverlight中代码:
<Grid x:Name="LayoutRoot" Background="White"> <Border BorderBrush="#FF5BB0FF" BorderThickness="1" Margin="0"> <Image x:Name="Image1" Margin="0" Stretch="None"/> </Border> </Grid>
private void UserControl_Loaded(object sender, RoutedEventArgs e) { //获取险情图片信息 getPictureInfoSoapClient client = new getPictureInfoSoapClient(); client.getSSXPictureQByIDCompleted += new EventHandler<getSSXPictureQByIDCompletedEventArgs>(client_getSSXPictureQByIDCompleted); client.getSSXPictureQByIDAsync(id); } //险情图片 void client_getSSXPictureQByIDCompleted(object sender, getSSXPictureQByIDCompletedEventArgs e) { MemoryStream ms = new MemoryStream(e.Result); BitmapImage image = new BitmapImage(); image.SetSource(ms); this.Image1.Source = image; }