Silverlight中通过调用WebService来显示数据库中以流形式保存的图片

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;
}