如何：列出已安装的解码器
更新：2007 年 11 月
可能需要列出计算机可用的图像解码器，以确定应用程序是否可以读取某种特定的图像文件格式。 ImageCodecInfo 类提供了 GetImageDecoders 静态方法，以便您可以确定有哪些图像解码器可供使用。GetImageDecoders 返回 ImageCodecInfo 对象数组。
示例
下面的代码示例输出已安装的解码器及其属性值的列表。
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
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);
}
编译代码
此示例需要：
Windows 窗体应用程序。
PaintEventArgs，它是 PaintEventHandler 的一个参数。