我想在XAML中绑定一个以varbinary类型保存在数据库中的图像。我能做到吗？
例如Northwind DataBase中的图片字段。
感谢
编辑1：）
我为转换图像字段编写此代码（Northwind DataBase中的Categories表中的图片字段），但每次出现异常时：
class ImageConverter : IValueConverter
{
object IValueConverter.Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (value == null) { return null; }
var image = (System.Drawing.Image)value;
var bitmap = new System.Windows.Media.Imaging.BitmapImage();
bitmap.BeginInit();
MemoryStream memoryStream = new MemoryStream();
image.Save(memoryStream, ImageFormat.Bmp);
memoryStream.Seek(0, System.IO.SeekOrigin.Begin);
bitmap.StreamSource = memoryStream;
bitmap.EndInit();
return bitmap;
}
object IValueConverter.ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new Exception("The method or operation is not implemented.");
}
}
并且：
class ImageConverter : IValueConverter
{
object IValueConverter.Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (value != null && value is byte[])
{
byte[] bytes = value as byte[];
MemoryStream stream = new MemoryStream(bytes);
BitmapImage image = new BitmapImage();
image.BeginInit();
image.StreamSource = stream;
image.EndInit();
return image;
}
return null;
}
object IValueConverter.ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new Exception("The method or operation is not implemented.");
}
}
和例外：
Provide value on 'System.Windows.Markup.StaticResourceHolder' threw an exception.
答案 0 :(得分：4)
如果从数据库获取字节数组，则无需将其转换为图像或位图图像... 您可以将图像的Source属性绑定到字节数组.wpf在内部处理字节数组，它将字节数组转换为图像...
修改
如果您仍想将字节数组转换为位图图像，则此方法是经过测试的方法
public BitmapImage ImageFromBytearray(byte[] imageData)
{
if (imageData == null)
return null;
MemoryStream strm = new MemoryStream();
strm.Write(imageData, 0, imageData.Length);
strm.Position = 0;
System.Drawing.Image img = System.Drawing.Image.FromStream(strm);
BitmapImage bitmapImage = new BitmapImage();
bitmapImage.BeginInit();
MemoryStream memoryStream = new MemoryStream();
img.Save(memoryStream, System.Drawing.Imaging.ImageFormat.Bmp);
memoryStream.Seek(0, SeekOrigin.Begin);
bitmapImage.StreamSource = memoryStream;
bitmapImage.EndInit();
return bitmapImage;
}
我使用上述方法创建了一个样本...
Xaml代码：
<Window x:Class="WpfApplication1.ImageFromByteArray"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="ImageFromByteArray" Height="300" Width="300" Name="Root">
<Grid>
<Image Source="{Binding ImageSource,ElementName=Root}" Height="300" Width="300" RenderOptions.BitmapScalingMode="HighQuality"/>
</Grid>
</Window>
代码背后
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using System.IO;
namespace WpfApplication1
{
/// <summary>
/// Interaction logic for ImageFromByteArray.xaml
/// </summary>
public partial class ImageFromByteArray : Window
{
public byte[] ByteArray
{
get
{
return (byte[])GetValue(ByteArrayProperty);
}
set
{
SetValue(ByteArrayProperty, value);
}
}
// Using a DependencyProperty as the backing store for ByteArray. This enables animation, styling, binding, etc...
public static readonly DependencyProperty ByteArrayProperty =
DependencyProperty.Register("ByteArray", typeof(byte[]), typeof(ImageFromByteArray));
public BitmapImage ImageSource
{
get { return (BitmapImage)GetValue(ImageSourceProperty); }
set { SetValue(ImageSourceProperty, value); }
}
// Using a DependencyProperty as the backing store for ImageSource. This enables animation, styling, binding, etc...
public static readonly DependencyProperty ImageSourceProperty =
DependencyProperty.Register("ImageSource", typeof(BitmapImage), typeof(ImageFromByteArray), new UIPropertyMetadata(null));
public ImageFromByteArray()
{
InitializeComponent();
Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog();
if (dlg.ShowDialog().GetValueOrDefault())
{
FileStream fs = new FileStream(dlg.FileName, FileMode.Open, FileAccess.Read);
ByteArray = new byte[fs.Length];
fs.Read(ByteArray, 0, System.Convert.ToInt32(fs.Length));
fs.Close();
ImageSource = ImageFromBytearray(ByteArray);
}
}
public BitmapImage ImageFromBytearray(byte[] imageData)
{
if (imageData == null)
return null;
MemoryStream strm = new MemoryStream();
strm.Write(imageData, 0, imageData.Length);
strm.Position = 0;
System.Drawing.Image img = System.Drawing.Image.FromStream(strm);
BitmapImage bitmapImage = new BitmapImage();
bitmapImage.BeginInit();
MemoryStream memoryStream = new MemoryStream();
img.Save(memoryStream, System.Drawing.Imaging.ImageFormat.Bmp);
memoryStream.Seek(0, SeekOrigin.Begin);
bitmapImage.StreamSource = memoryStream;
bitmapImage.EndInit();
return bitmapImage;
}
}
}
希望这会对你有帮助......
答案 1 :(得分：0)