Silverlight &Windows phone7 中使用Isolated Storage存储与读取图片
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1.将ImageSource转化成WriteableBitmap
var bitmap= new System.Windows.Media.Imaging.WriteableBitmap((System.Windows.Media.Imaging.BitmapSource)this.imgCreatedTag.Source);
2.代码：
///
<summary>
///
载入指定名称的图片
///
</summary>
///
<param name="fileName"></param>
///
<returns>
返回指定文件的byte[]流
</returns>
private
static
byte
[] _LoadIfExists(
string
fileName)
{
byte
[] retVal;
using
(IsolatedStorageFile iso
=
IsolatedStorageFile.GetUserStoreForApplication())
{
if
(iso.FileExists(fileName))
{
using
(IsolatedStorageFileStream stream
=
iso.OpenFile(fileName, FileMode.Open))
{
retVal
=
new
byte
[stream.Length];
stream.Read(retVal,
0
, retVal.Length);
}
}
else
{
retVal
=
new
byte
[
0
];
}
}
return
retVal;
}
///
<summary>
///
保存byte[]流到Storage
///
</summary>
///
<param name="buffer"></param>
///
<param name="fileName"></param>
private
static
void
_SaveToDisk(
byte
[] buffer,
string
fileName)
{
using
(IsolatedStorageFile iso
=
IsolatedStorageFile.GetUserStoreForApplication())
{
using
(
IsolatedStorageFileStream stream
=
new
IsolatedStorageFileStream(fileName, FileMode.CreateNew,
iso))
{
stream.Write(buffer,
0
, buffer.Length);
}
}
}
///
<summary>
///
从Storage获取图片
///
</summary>
///
<param name="buffer">
图片的byte[]流
</param>
///
<returns></returns>
private
static
WriteableBitmap _GetImage(
byte
[] buffer)
{
int
width
=
buffer[
0
]
*
256
+
buffer[
1
];
int
height
=
buffer[
2
]
*
256
+
buffer[
3
];
long
matrixSize
=
width
*
height;
WriteableBitmap retVal
=
new
WriteableBitmap(width, height);
int
bufferPos
=
4
;
for
(
int
matrixPos
=
0
; matrixPos
<
matrixSize; matrixPos
++
)
{
int
pixel
=
buffer[bufferPos
++
];
pixel
=
pixel
<<
8
|
buffer[bufferPos
++
];
pixel
=
pixel
<<
8
|
buffer[bufferPos
++
];
pixel
=
pixel
<<
8
|
buffer[bufferPos
++
];
retVal.Pixels[matrixPos]
=
pixel;
}
return
retVal;
}
///
<summary>
///
将图片转换成byte[]流
///
</summary>
///
<param name="bitmap"></param>
///
<returns></returns>
private
static
byte
[] _GetSaveBuffer(WriteableBitmap bitmap)
{
long
matrixSize
=
bitmap.PixelWidth
*
bitmap.PixelHeight;
long
byteSize
=
matrixSize
*
4
+
4
;
byte
[] retVal
=
new
byte
[byteSize];
long
bufferPos
=
0
;
retVal[bufferPos
++
]
=
(
byte
)((bitmap.PixelWidth
/
256
)
&
0xff
);
retVal[bufferPos
++
]
=
(
byte
)((bitmap.PixelWidth
%
256
)
&
0xff
);
retVal[bufferPos
++
]
=
(
byte
)((bitmap.PixelHeight
/
256
)
&
0xff
);
retVal[bufferPos
++
]
=
(
byte
)((bitmap.PixelHeight
%
256
)
&
0xff
);
for
(
int
matrixPos
=
0
; matrixPos
<
matrixSize; matrixPos
++
)
{
retVal[bufferPos
++
]
=
(
byte
)((bitmap.Pixels[matrixPos]
>>
24
)
&
0xff
);
retVal[bufferPos
++
]
=
(
byte
)((bitmap.Pixels[matrixPos]
>>
16
)
&
0xff
);
retVal[bufferPos
++
]
=
(
byte
)((bitmap.Pixels[matrixPos]
>>
8
)
&
0xff
);
retVal[bufferPos
++
]
=
(
byte
)((bitmap.Pixels[matrixPos])
&
0xff
);
}
return
retVal;
}