BitmapImage.BeginInit 方法

定義

表示 BitmapImage 初始化開始。Signals the start of the BitmapImage initialization.

public:
 virtual void BeginInit();
public void BeginInit ();
abstract member BeginInit : unit -> unit
override this.BeginInit : unit -> unit
Public Sub BeginInit ()

實作

例外狀況

BitmapImage 目前正在起始。The BitmapImage is currently being initialized. 已經呼叫 BeginInit()BeginInit() has already been called.

-或--or- BitmapImage 已經完成初始化。The BitmapImage has already been initialized.

範例

下列範例示範如何BitmapImage BeginInit使用和EndInit方法, 初始化具有一組屬性的。The following example demonstrates how to initialize a BitmapImage with a set of properties by using the BeginInit and EndInit methods.

// Define a BitmapImage.
Image myImage = new Image();
BitmapImage bi = new BitmapImage();

// Begin initialization.
bi.BeginInit();

// Set properties.
bi.CacheOption = BitmapCacheOption.OnDemand;
bi.CreateOptions = BitmapCreateOptions.DelayCreation;
bi.DecodePixelHeight = 125;
bi.DecodePixelWidth = 125;
bi.Rotation = Rotation.Rotate90;
MessageBox.Show(bi.IsDownloading.ToString());
bi.UriSource = new Uri("smiley.png", UriKind.Relative);

// End initialization.
bi.EndInit();
myImage.Source = bi;
myImage.Stretch = Stretch.None;
myImage.Margin = new Thickness(5);
' Define a BitmapImage.
Dim myImage As New Image()
Dim bi As New BitmapImage()

' Begin initialization.
bi.BeginInit()

' Set properties.
bi.CacheOption = BitmapCacheOption.OnDemand
bi.CreateOptions = BitmapCreateOptions.DelayCreation
bi.DecodePixelHeight = 125
bi.DecodePixelWidth = 125
bi.Rotation = Rotation.Rotate90
MessageBox.Show(bi.IsDownloading.ToString())
bi.UriSource = New Uri("smiley.png", UriKind.Relative)

' End initialization.
bi.EndInit()
myImage.Source = bi
myImage.Stretch = Stretch.None
myImage.Margin = New Thickness(5)

備註

必須在和BeginInit EndInit呼叫之間進行屬性初始化。Property initialization must be done between BeginInit and EndInit calls. BitmapImage一旦初始化之後, 屬性變更就會被忽略。Once the BitmapImage has been initialized, property changes are ignored.

適用於

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