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Guide pratique pour répertorier les décodeurs installés

  • Article

Vous pouvez répertorier les décodeurs d’images disponibles sur un ordinateur pour déterminer si votre application peut lire un format de fichier image particulier. La classe ImageCodecInfo fournit les méthodes statiques GetImageDecoders afin de déterminer les décodeurs d’images disponibles. GetImageDecoders retourne un tableau d’objets ImageCodecInfo.

Exemple

L’exemple de code suivant génère la liste des décodeurs installés et leurs valeurs de propriété.

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

Compilation du code

Cet exemple nécessite :

Voir aussi