PngBitmapDecoder 构造函数

定义

命名空间:: System.Windows.Media.Imaging

程序集:: PresentationCore.dll

重要

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初始化的新 PngBitmapDecoder实例。

重载

名称	说明
PngBitmapDecoder(Stream, BitmapCreateOptions, BitmapCacheOption)	PngBitmapDecoder使用指定的`createOptions`和 `cacheOption`。
PngBitmapDecoder(Uri, BitmapCreateOptions, BitmapCacheOption)	用PngBitmapDecoder指定的Uri`createOptions`和 `cacheOption`。

PngBitmapDecoder(Stream, BitmapCreateOptions, BitmapCacheOption)

PngBitmapDecoder使用指定的createOptions和 cacheOption。

public:
 PngBitmapDecoder(System::IO::Stream ^ bitmapStream, System::Windows::Media::Imaging::BitmapCreateOptions createOptions, System::Windows::Media::Imaging::BitmapCacheOption cacheOption);

[System.Security.SecurityCritical]
public PngBitmapDecoder(System.IO.Stream bitmapStream, System.Windows.Media.Imaging.BitmapCreateOptions createOptions, System.Windows.Media.Imaging.BitmapCacheOption cacheOption);

public PngBitmapDecoder(System.IO.Stream bitmapStream, System.Windows.Media.Imaging.BitmapCreateOptions createOptions, System.Windows.Media.Imaging.BitmapCacheOption cacheOption);

[<System.Security.SecurityCritical>]
new System.Windows.Media.Imaging.PngBitmapDecoder : System.IO.Stream * System.Windows.Media.Imaging.BitmapCreateOptions * System.Windows.Media.Imaging.BitmapCacheOption -> System.Windows.Media.Imaging.PngBitmapDecoder

new System.Windows.Media.Imaging.PngBitmapDecoder : System.IO.Stream * System.Windows.Media.Imaging.BitmapCreateOptions * System.Windows.Media.Imaging.BitmapCacheOption -> System.Windows.Media.Imaging.PngBitmapDecoder

Public Sub New (bitmapStream As Stream, createOptions As BitmapCreateOptions, cacheOption As BitmapCacheOption)

参数

bitmapStream: Stream

要解码的位图流。

createOptions: BitmapCreateOptions

位图图像的初始化选项。

cacheOption: BitmapCacheOption

用于位图图像的缓存方法。

属性: SecurityCriticalAttribute

例外

ArgumentNullException

值为 bitmapStreamnull.

FileFormatException

该 bitmapStream 图像不是可移植网络图形（PNG）编码的图像。

示例

下面的代码示例演示如何创建文件流中的实例并使用 PngBitmapDecoder 实例。解码的图像用作控件的 Image 源。


// Open a Stream and decode a PNG image
Stream^ imageStreamSource = gcnew FileStream("smiley.png", FileMode::Open, FileAccess::Read, FileShare::Read);
PngBitmapDecoder^ decoder = gcnew PngBitmapDecoder(imageStreamSource, BitmapCreateOptions::PreservePixelFormat, BitmapCacheOption::Default);
BitmapSource^ bitmapSource = decoder->Frames[0];

// Draw the Image
Image^ myImage = gcnew Image();
myImage->Source = bitmapSource;
myImage->Stretch = Stretch::None;
myImage->Margin = System::Windows::Thickness(20);


// Open a Stream and decode a PNG image
Stream imageStreamSource = new FileStream("smiley.png", FileMode.Open, FileAccess.Read, FileShare.Read);
PngBitmapDecoder decoder = new PngBitmapDecoder(imageStreamSource, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
BitmapSource bitmapSource = decoder.Frames[0];

// Draw the Image
Image myImage = new Image();
myImage.Source = bitmapSource;
myImage.Stretch = Stretch.None;
myImage.Margin = new Thickness(20);

' Open a Stream and decode a PNG image
Dim imageStreamSource As New FileStream("smiley.png", FileMode.Open, FileAccess.Read, FileShare.Read)
Dim decoder As New PngBitmapDecoder(imageStreamSource, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default)
Dim bitmapSource As BitmapSource = decoder.Frames(0)

' Draw the Image
Dim myImage As New Image()
myImage.Source = bitmapSource
myImage.Stretch = Stretch.None
myImage.Margin = New Thickness(20)

注解

OnLoad如果要在创建解码器后关闭bitmapStream缓存选项。默认 OnDemand 缓存选项将保留对流的访问，直到需要位图并由垃圾回收器处理清理。

适用于

PngBitmapDecoder(Uri, BitmapCreateOptions, BitmapCacheOption)

用PngBitmapDecoder指定的UricreateOptions和 cacheOption。

public:
 PngBitmapDecoder(Uri ^ bitmapUri, System::Windows::Media::Imaging::BitmapCreateOptions createOptions, System::Windows::Media::Imaging::BitmapCacheOption cacheOption);

[System.Security.SecurityCritical]
public PngBitmapDecoder(Uri bitmapUri, System.Windows.Media.Imaging.BitmapCreateOptions createOptions, System.Windows.Media.Imaging.BitmapCacheOption cacheOption);

public PngBitmapDecoder(Uri bitmapUri, System.Windows.Media.Imaging.BitmapCreateOptions createOptions, System.Windows.Media.Imaging.BitmapCacheOption cacheOption);

[<System.Security.SecurityCritical>]
new System.Windows.Media.Imaging.PngBitmapDecoder : Uri * System.Windows.Media.Imaging.BitmapCreateOptions * System.Windows.Media.Imaging.BitmapCacheOption -> System.Windows.Media.Imaging.PngBitmapDecoder

new System.Windows.Media.Imaging.PngBitmapDecoder : Uri * System.Windows.Media.Imaging.BitmapCreateOptions * System.Windows.Media.Imaging.BitmapCacheOption -> System.Windows.Media.Imaging.PngBitmapDecoder

Public Sub New (bitmapUri As Uri, createOptions As BitmapCreateOptions, cacheOption As BitmapCacheOption)

参数

bitmapUri: Uri

用于 Uri 标识要解码的位图。

createOptions: BitmapCreateOptions

位图图像的初始化选项。

cacheOption: BitmapCacheOption

用于位图图像的缓存方法。

属性: SecurityCriticalAttribute

例外

ArgumentNullException

值为 bitmapUrinull.

FileFormatException

该 bitmapUri 图像不是可移植网络图形（PNG）编码的图像。

示例

下面的代码示例演示如何创建一个实例并使用 PngBitmapDecoder a.Uri 解码的图像用作控件的 Image 源。


// Open a Uri and decode a PNG image
System::Uri^ myUri = gcnew System::Uri("smiley.png", UriKind::RelativeOrAbsolute);
PngBitmapDecoder^ decoder2 = gcnew PngBitmapDecoder(myUri, BitmapCreateOptions::PreservePixelFormat, BitmapCacheOption::Default);
BitmapSource^ bitmapSource2 = decoder2->Frames[0];

// Draw the Image
Image^ myImage2 = gcnew Image();
myImage2->Source = bitmapSource2;
myImage2->Stretch = Stretch::None;
myImage2->Margin = System::Windows::Thickness(20);


// Open a Uri and decode a PNG image
Uri myUri = new Uri("smiley.png", UriKind.RelativeOrAbsolute);
PngBitmapDecoder decoder2 = new PngBitmapDecoder(myUri, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
BitmapSource bitmapSource2 = decoder2.Frames[0];

// Draw the Image
Image myImage2 = new Image();
myImage2.Source = bitmapSource2;
myImage2.Stretch = Stretch.None;
myImage2.Margin = new Thickness(20);

' Open a Uri and decode a PNG image
Dim myUri As New Uri("smiley.png", UriKind.RelativeOrAbsolute)
Dim decoder2 As New PngBitmapDecoder(myUri, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default)
Dim bitmapSource2 As BitmapSource = decoder2.Frames(0)

' Draw the Image
Dim myImage2 As New Image()
myImage2.Source = bitmapSource2
myImage2.Stretch = Stretch.None
myImage2.Margin = New Thickness(20)

适用于

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