Metafile 类

定义图形图元文件。图元文件包含描述一系列图形操作的记录，这些操作可以被记录（构造）和被回放（显示）。此类不能继承。

**命名空间:**System.Drawing.Imaging
**程序集:**System.Drawing（在 system.drawing.dll 中）

语法

声明
<SerializableAttribute> _
Public NotInheritable Class Metafile
    Inherits Image
用法
Dim instance As Metafile

[SerializableAttribute] 
public sealed class Metafile : Image

[SerializableAttribute] 
public ref class Metafile sealed : public Image

/** @attribute SerializableAttribute() */ 
public final class Metafile extends Image

SerializableAttribute 
public final class Metafile extends Image

备注

使用 Save 方法将图形图像保存为 Windows 图元文件格式 (WMF) 或增强型图元文件格式 (EMF) 文件时，结果文件将另存为可移植网络图形 (PNG) 文件。发生此行为是由于 .NET Framework 的 GDI+ 组件没有可用来将文件另存为 .wmf 或 .emf 文件的编码器。

示例

下面的代码示例演示如何创建 Metafile 并使用 PlayRecord 方法。

Imports System
Imports System.Drawing
Imports System.Drawing.Imaging
Imports System.Windows.Forms
' for Marshal.Copy
Imports System.Runtime.InteropServices


Public Class Form1
    Inherits Form
    Private metafile1 As Metafile
    Private metafileDelegate As Graphics.EnumerateMetafileProc
    Private destPoint As Point
    
    Public Sub New() 
        metafile1 = New Metafile("C:\test.wmf")
        metafileDelegate = New Graphics.EnumerateMetafileProc(AddressOf MetafileCallback)
        destPoint = New Point(20, 10)
    
    End Sub
    
    Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs) 
        e.Graphics.EnumerateMetafile(metafile1, destPoint, metafileDelegate)
    
    End Sub
    
    Private Function MetafileCallback(ByVal recordType As _
        EmfPlusRecordType, ByVal flags As Integer, ByVal dataSize As Integer, _
        ByVal data As IntPtr, ByVal callbackData As PlayRecordCallback) As Boolean

        Dim dataArray As Byte() = Nothing
        If data <> IntPtr.Zero Then

            ' Copy the unmanaged record to a managed byte buffer 
            ' that can be used by PlayRecord.
            dataArray = New Byte(dataSize) {}
            Marshal.Copy(data, dataArray, 0, dataSize)
        End If

        metafile1.PlayRecord(recordType, flags, dataSize, dataArray)
        Return True

    End Function
    
    Shared Sub Main() 
        Application.Run(New Form1())
    End Sub

End Class

using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Windows.Forms;

// for Marshal.Copy
using System.Runtime.InteropServices; 

public class Form1 : Form
{
    private Metafile metafile1;
    private Graphics.EnumerateMetafileProc metafileDelegate;
    private Point destPoint;
    public Form1()
    {
        metafile1 = new Metafile(@"C:\Test.wmf");
        metafileDelegate = new Graphics.EnumerateMetafileProc(MetafileCallback);
        destPoint = new Point(20, 10);
    }
    protected override void OnPaint(PaintEventArgs e)
    {
        e.Graphics.EnumerateMetafile(metafile1, destPoint, metafileDelegate);
    }
    private bool MetafileCallback(
       EmfPlusRecordType recordType,
       int flags,
       int dataSize,
       IntPtr data,
       PlayRecordCallback callbackData)
    {
        byte[] dataArray = null;
        if (data != IntPtr.Zero)
        {
            // Copy the unmanaged record to a managed byte buffer 
            // that can be used by PlayRecord.
            dataArray = new byte[dataSize];
            Marshal.Copy(data, dataArray, 0, dataSize);
        }

        metafile1.PlayRecord(recordType, flags, dataSize, dataArray);

        return true;
    }

    static void Main()
    {
        Application.Run(new Form1());
    }
}

继承层次结构

System.Object
   System.MarshalByRefObject
     System.Drawing.Image
      System.Drawing.Imaging.Metafile

线程安全

此类型的任何公共静态（Visual Basic 中的 Shared）成员都是线程安全的，但不保证所有实例成员都是线程安全的。

平台

Windows 98、Windows 2000 SP4、Windows Millennium Edition、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

Metafile 成员
System.Drawing.Imaging 命名空间