Image.PropertyItems 属性
获取存储于该 Image 中的所有属性项（元数据片）。
**命名空间:**System.Drawing
**程序集:**System.Drawing（在 system.drawing.dll 中）
语法
声明
Public ReadOnly Property PropertyItems As PropertyItem()
用法
Dim instance As Image
Dim value As PropertyItem()
value = instance.PropertyItems
public PropertyItem[] PropertyItems { get; }
public:
property array<PropertyItem^>^ PropertyItems {
array<PropertyItem^>^ get ();
}
/** @property */
public PropertyItem[] get_PropertyItems ()
public function get PropertyItems () : PropertyItem[]
属性值
由 PropertyItem 对象组成的一个数组，这些对象分别对应于此图像中存储的每个属性项。
备注
如果图像没有属性项或者图像格式不支持属性项，则 PropertyItems 将返回空数组（即长度为零的数组）。
示例
下面的代码示例演示如何使用 System.Drawing.Imaging.PropertyItem 类和 PropertyItems 属性读取和显示一个图像文件中的元数据。
该示例旨在使用导入 System.Drawing.Imaging 命名空间的 Windows 窗体。将该代码粘贴到窗体中，并将路径更改为 fakePhoto.jpg，以指向系统中的一个图像文件。处理窗体的 Paint 事件时，调用 ExtractMetaData 方法，将 e 作为 PaintEventArgs 传递。
Private Sub ExtractMetaData(ByVal e As PaintEventArgs)
Try
'Create an Image object.
Dim theImage As Image = New Bitmap("c:\fakePhoto.jpg")
'Get the PropertyItems property from image.
Dim propItems As PropertyItem() = theImage.PropertyItems
'Set up the display.
Dim font As New font("Arial", 10)
Dim blackBrush As New SolidBrush(Color.Black)
Dim X As Integer = 0
Dim Y As Integer = 0
'For each PropertyItem in the array, display the id, type, and length.
Dim count As Integer = 0
Dim propItem As PropertyItem
For Each propItem In propItems
e.Graphics.DrawString("Property Item " + count.ToString(), _
font, blackBrush, X, Y)
Y += font.Height
e.Graphics.DrawString(" iD: 0x" & propItem.Id.ToString("x"), _
font, blackBrush, X, Y)
Y += font.Height
e.Graphics.DrawString(" type: " & propItem.Type.ToString(), _
font, blackBrush, X, Y)
Y += font.Height
e.Graphics.DrawString(" length: " & propItem.Len.ToString() & _
" bytes", font, blackBrush, X, Y)
Y += font.Height
count += 1
Next propItem
font.Dispose()
Catch ex As ArgumentException
MessageBox.Show("There was an error. Make sure the path to the image file is valid.")
End Try
End Sub
private void ExtractMetaData(PaintEventArgs e)
{
try
{
// Create an Image object.
Image theImage = new Bitmap("c:\\fakePhoto.jpg");
// Get the PropertyItems property from image.
PropertyItem[] propItems = theImage.PropertyItems;
// Set up the display.
Font font1 = new Font("Arial", 10);
SolidBrush blackBrush = new SolidBrush(Color.Black);
int X = 0;
int Y = 0;
// For each PropertyItem in the array, display the id,
// type, and length.
int count = 0;
foreach ( PropertyItem propItem in propItems )
{
e.Graphics.DrawString("Property Item " +
count.ToString(), font1, blackBrush, X, Y);
Y += font1.Height;
e.Graphics.DrawString(" ID: 0x" +
propItem.Id.ToString("x"), font1, blackBrush, X, Y);
Y += font1.Height;
e.Graphics.DrawString(" type: " +
propItem.Type.ToString(), font1, blackBrush, X, Y);
Y += font1.Height;
e.Graphics.DrawString(" length: " +
propItem.Len.ToString() +
" bytes", font1, blackBrush, X, Y);
Y += font1.Height;
count += 1;
}
font1.Dispose();
}
catch(Exception)
{
MessageBox.Show("There was an error." +
"Make sure the path to the image file is valid.");
}
}
private:
void ExtractMetaData( PaintEventArgs^ e )
{
try
{
// Create an Image object.
Image^ theImage = gcnew Bitmap( "c:\\fakePhoto.jpg" );
// Get the PropertyItems property from image.
array<PropertyItem^>^propItems = theImage->PropertyItems;
// Set up the display.
System::Drawing::Font^ font1 = gcnew System::Drawing::Font( "Arial",10 );
SolidBrush^ blackBrush = gcnew SolidBrush( Color::Black );
int X = 0;
int Y = 0;
// For each PropertyItem in the array, display the id,
// type, and length.
int count = 0;
System::Collections::IEnumerator^ myEnum = propItems->GetEnumerator();
while ( myEnum->MoveNext() )
{
PropertyItem^ propItem = safe_cast<PropertyItem^>(myEnum->Current);
e->Graphics->DrawString( String::Format( "Property Item {0}", count ), font1, blackBrush, (float)X, (float)Y );
Y += font1->Height;
e->Graphics->DrawString( String::Format( " ID: 0x{0}", propItem->Id.ToString( "x" ) ), font1, blackBrush, (float)X, (float)Y );
Y += font1->Height;
e->Graphics->DrawString( String::Format( " type: {0}", propItem->Type ), font1, blackBrush, (float)X, (float)Y );
Y += font1->Height;
e->Graphics->DrawString( String::Format( " length: {0} bytes", propItem->Len ), font1, blackBrush, (float)X, (float)Y );
Y += font1->Height;
count += 1;
}
delete font1;
}
catch ( Exception^ )
{
MessageBox::Show( "There was an error."
"Make sure the path to the image file is valid." );
}
}
private void ExtractMetaData(PaintEventArgs e)
{
try {
// Create an Image object.
Image theImage = new Bitmap("c:\\fakePhoto.jpg");
// Get the PropertyItems property from image.
PropertyItem propItems[] = theImage.get_PropertyItems();
// Set up the display.
Font font1 = new Font("Arial", 10);
SolidBrush blackBrush = new SolidBrush(Color.get_Black());
int X = 0;
int Y = 0;
// For each PropertyItem in the array, display the id,
// type, and length.
int count = 0;
//foreach (PropertyItem propItem in propItems)
for (int iCtr = 0; iCtr < propItems.length; iCtr++) {
PropertyItem propItem = propItems[iCtr];
e.get_Graphics().DrawString("Property Item "
+ System.Convert.ToString(count), font1, blackBrush, X, Y);
Y += font1.get_Height();
e.get_Graphics().DrawString(" ID: 0x"
+ ((System.Int32)propItem.get_Id()).ToString("x"), font1,
blackBrush, X, Y);
Y += font1.get_Height();
e.get_Graphics().DrawString(" type: "
+ System.Convert.ToString(propItem.get_Type()), font1,
blackBrush, X, Y);
Y += font1.get_Height();
e.get_Graphics().DrawString(" length: "
+ System.Convert.ToString(propItem.get_Len()) + " bytes",
font1, blackBrush, X, Y);
Y += font1.get_Height();
count += 1;
}
font1.Dispose();
}
catch (System.Exception exp) {
MessageBox.Show(("There was an error."
+ "Make sure the path to the image file is valid."));
}
} //ExtractMetaData
平台
Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition
.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。
版本信息
.NET Framework
受以下版本支持：2.0、1.1、1.0
请参见
参考
Image 类
Image 成员
System.Drawing 命名空间