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Anleitung: Installierte Decoder auflisten

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Möglicherweise möchten Sie die auf einem Computer verfügbaren Bilddecoder auflisten, um festzustellen, ob Ihre Anwendung ein bestimmtes Bilddateiformat lesen kann. Die ImageCodecInfo-Klasse stellt die GetImageDecoders statischen Methoden bereit, sodass Sie bestimmen können, welche Bilddecoder verfügbar sind. GetImageDecoders gibt ein Array von ImageCodecInfo Objekten zurück.

Beispiel

Im folgenden Codebeispiel wird die Liste der installierten Decoder und deren Eigenschaftswerte ausgegeben.

private void GetImageDecodersExample(PaintEventArgs e)
{
    // Get an array of available decoders.
    ImageCodecInfo[] myCodecs;
    myCodecs = ImageCodecInfo.GetImageDecoders();
    int numCodecs = myCodecs.GetLength(0);

    // Set up display variables.
    Color foreColor = Color.Black;
    Font font = new Font("Arial", 8);
    int i = 0;

    // Check to determine whether any codecs were found.
    if (numCodecs > 0)
    {
        // Set up an array to hold codec information. There are 9
        // information elements plus 1 space for each codec, so 10 times
        // the number of codecs found is allocated.
        string[] myCodecInfo = new string[numCodecs * 10];

        // Write all the codec information to the array.
        for (i = 0; i < numCodecs; i++)
        {
            myCodecInfo[i * 10] = "Codec Name = " + myCodecs[i].CodecName;
            myCodecInfo[(i * 10) + 1] = "Class ID = " +
                myCodecs[i].Clsid.ToString();
            myCodecInfo[(i * 10) + 2] = "DLL Name = " + myCodecs[i].DllName;
            myCodecInfo[(i * 10) + 3] = "Filename Ext. = " +
                myCodecs[i].FilenameExtension;
            myCodecInfo[(i * 10) + 4] = "Flags = " +
                myCodecs[i].Flags.ToString();
            myCodecInfo[(i * 10) + 5] = "Format Descrip. = " +
                myCodecs[i].FormatDescription;
            myCodecInfo[(i * 10) + 6] = "Format ID = " +
                myCodecs[i].FormatID.ToString();
            myCodecInfo[(i * 10) + 7] = "MimeType = " + myCodecs[i].MimeType;
            myCodecInfo[(i * 10) + 8] = "Version = " +
                myCodecs[i].Version.ToString();
            myCodecInfo[(i * 10) + 9] = " ";
        }
        int numMyCodecInfo = myCodecInfo.GetLength(0);

        // Render all of the information to the screen.
        int j = 20;
        for (i = 0; i < numMyCodecInfo; i++)
        {
            e.Graphics.DrawString(myCodecInfo[i],
                font,
                new SolidBrush(foreColor),
                20,
                j);
            j += 12;
        }
    }
    else
        e.Graphics.DrawString("No Codecs Found",
            font,
            new SolidBrush(foreColor),
            20,
            20);
}

Private Sub GetImageDecodersExample(ByVal e As PaintEventArgs)
    ' Get an array of available decoders.
    Dim myCodecs() As ImageCodecInfo
    myCodecs = ImageCodecInfo.GetImageDecoders()
    Dim numCodecs As Integer = myCodecs.GetLength(0)

    ' Set up display variables.
    Dim foreColor As Color = Color.Black
    Dim font As New Font("Arial", 8)
    Dim i As Integer = 0

    ' Check to determine whether any codecs were found.
    If numCodecs > 0 Then
        ' Set up an array to hold codec information. There are 9
        ' information elements plus 1 space for each codec, so 10 times
        ' the number of codecs found is allocated.
        Dim myCodecInfo(numCodecs * 10) As String

        ' Write all the codec information to the array.
        For i = 0 To numCodecs - 1
            myCodecInfo((i * 10)) = "Codec Name = " + myCodecs(i).CodecName
            myCodecInfo((i * 10 + 1)) = "Class ID = " + myCodecs(i).Clsid.ToString()
            myCodecInfo((i * 10 + 2)) = "DLL Name = " + myCodecs(i).DllName
            myCodecInfo((i * 10 + 3)) = "Filename Ext. = " + myCodecs(i).FilenameExtension
            myCodecInfo((i * 10 + 4)) = "Flags = " + myCodecs(i).Flags.ToString()
            myCodecInfo((i * 10 + 5)) = "Format Descrip. = " + myCodecs(i).FormatDescription
            myCodecInfo((i * 10 + 6)) = "Format ID = " + myCodecs(i).FormatID.ToString()
            myCodecInfo((i * 10 + 7)) = "MimeType = " + myCodecs(i).MimeType
            myCodecInfo((i * 10 + 8)) = "Version = " + myCodecs(i).Version.ToString()
            myCodecInfo((i * 10 + 9)) = " "
        Next i
        Dim numMyCodecInfo As Integer = myCodecInfo.GetLength(0)

        ' Render all of the information to the screen.
        Dim j As Integer = 20
        For i = 0 To numMyCodecInfo - 1
            e.Graphics.DrawString(myCodecInfo(i), _
                font, New SolidBrush(foreColor), 20, j)
            j += 12
        Next i
    Else
        e.Graphics.DrawString("No Codecs Found", _
            font, New SolidBrush(foreColor), 20, 20)
    End If
End Sub

Kompilieren des Codes

In diesem Beispiel ist Folgendes erforderlich:

Siehe auch