BitmapMetadata.SetQuery(String, Object) 方法

public:
 void SetQuery(System::String ^ query, System::Object ^ value);

[System.Security.SecurityCritical]
public void SetQuery(string query, object value);

public void SetQuery(string query, object value);

[<System.Security.SecurityCritical>]
member this.SetQuery : string * obj -> unit

member this.SetQuery : string * obj -> unit

Public Sub SetQuery (query As String, value As Object)

參數

屬性

SecurityCriticalAttribute

範例

以下程式碼範例示範如何使用此 SetQuery 方法將元資料寫入可攜式網路圖形（PNG）檔案。

Stream^ pngStream = gcnew FileStream("smiley.png", FileMode::Open, FileAccess::ReadWrite, FileShare::ReadWrite);
PngBitmapDecoder^ pngDecoder = gcnew PngBitmapDecoder(pngStream, BitmapCreateOptions::PreservePixelFormat, BitmapCacheOption::Default);
BitmapFrame^ pngFrame = pngDecoder->Frames[0];
InPlaceBitmapMetadataWriter^ pngInplace = pngFrame->CreateInPlaceBitmapMetadataWriter();
if (pngInplace->TrySave())
{
   pngInplace->SetQuery("/Text/Description", "Have a nice day.");
}
pngStream->Close();

Stream pngStream = new System.IO.FileStream("smiley.png", FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
PngBitmapDecoder pngDecoder = new PngBitmapDecoder(pngStream, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default);
BitmapFrame pngFrame = pngDecoder.Frames[0];
InPlaceBitmapMetadataWriter pngInplace = pngFrame.CreateInPlaceBitmapMetadataWriter();
if (pngInplace.TrySave())
{ pngInplace.SetQuery("/Text/Description", "Have a nice day."); }
pngStream.Close();

Dim pngStream As New System.IO.FileStream("smiley.png", FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite)
Dim pngDecoder As New PngBitmapDecoder(pngStream, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.Default)
Dim pngFrame As BitmapFrame = pngDecoder.Frames(0)
Dim pngInplace As InPlaceBitmapMetadataWriter = pngFrame.CreateInPlaceBitmapMetadataWriter()
If pngInplace.TrySave() = True Then
    pngInplace.SetQuery("/Text/Description", "Have a nice day.")
End If
pngStream.Close()

在寫入中繼資料後， GetQuery 該方法會讀取該資料並以文字字串的形式輸出。

// Add the metadata of the bitmap image to the text block.
TextBlock^ myTextBlock = gcnew TextBlock();
myTextBlock->Text = "The Description metadata of this image is: " + pngInplace->GetQuery("/Text/Description")->ToString();

// Add the metadata of the bitmap image to the text block.
TextBlock myTextBlock = new TextBlock();
myTextBlock.Text = "The Description metadata of this image is: " + pngInplace.GetQuery("/Text/Description").ToString();

' Add the metadata of the bitmap image to the text block.
Dim myTextBlock As New TextBlock()
myTextBlock.Text = "The Description metadata of this image is: " + pngInplace.GetQuery("/Text/Description").ToString()

備註

與影像相關的元資料是指描述影像但並非顯示影像所必需的資料。 每種支援的點陣圖影像格式處理元資料的方式不同，但讀寫元資料的功能相同。

Windows Presentation Foundation（WPF）支援以下影像元資料架構：可交換影像檔案（Exif）、tEXt（PNG 文字資料）、影像檔案目錄（IFD）、國際新聞電信理事會（IPTC）及可擴充元資料平台（XMP）。

另請參閱

• 可攜式網路圖形文字資料（tEXt）規範
• 國際新聞電信理事會（IPTC）架構資訊
• Adobe 可擴充元資料平台（XMP）
• EXIF（可交換影像檔案格式）規範