c# – 如何在使用MEF的插件DLL的元数据中包含图像？
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C#.NET 4.0 WinForms
我开始实现this tutorial中的MEF示例代码,该代码描述了为元数据创建自定义ExportAttribute属性.在我尝试在元数据中包含资源文件中的图像之前,一切都在顺利进行.目标是将每个插件DLL的标题,描述和图标提取为元数据,以便在主程序中构建插件菜单. 我现在得到编译错误：
所以现在我有一个问题,需要弄清楚： 1)如何在属性中包含图像？ 要么 2)如何在不使用属性的情况下在MEF中包含元数据？ 这是我正在使用的代码： 在合同类中： // Metadata contract interface
public interface IPlugInMetadata
{
string PlugInTitle { get; }
string PlugInDescription { get; }
Image PlugInIcon { get; }
}
// Plug-In contract interface
public interface IPlugIn
{
void StartPlugIn(object systemObject);
void StopPlugin();
}
插件DLL中的自定义属性： [MetadataAttribute]
[AttributeUsage(AttributeTargets.Class,AllowMultiple = false)]
public class PluginMetadataAttribute : ExportAttribute
{
public string title { get; set; }
public string description { get; set; }
public Image icon { get; set; }
public PluginMetadataAttribute(string plugInTitle,string plugInDescription,Image plugInIcon)
: base(typeof(IPlugInMetadata))
{
title = plugInTitle;
description = plugInDescription;
icon = plugInIcon;
}
}
最后,Plug-In DLL中的Program类： [Export(typeof(IPlugIn))]
[PluginMetadata(ResourceFile.PlugInTitle,ResourceFile.PlugInDescription,ResourceFile.PlugInIcon24)]
public class Program : IPlugIn
{
public void StartPlugIn(object systemObject)
{
Console.WriteLine("Start Plug-In: " + ResourceFile.PlugInTitle);
}
public void StopPlugin()
{
Console.WriteLine("Stop Plug-In: " + ResourceFile.PlugInTitle);
}
}
这条线产生错误. [PluginMetadata(ResourceFile.PlugInTitle,ResourceFile.PlugInIcon24)] 显然,ResourceFile不被视为常量,但是我如何将图像用作元数据,或者这是不可能的？ (请注意,图像设置为“嵌入.resx”) 感谢您的任何帮助或建议！ 解决方法
找到了解决方案：
好的,据我所知,你不能在MEF元数据中使用图像或图标.但是,您可以为DLL文件指定一个图标,就像为EXE文件一样.然后可以使用.NET类型中内置的静态方法读取图标： Icon MyDLLIcon = Icon.ExtractAssociatedIcon(DLLFilePath); 我仍然不确定为什么你可以将资源文件中的字符串作为MEF元数据返回,而不是嵌入的图标或图像. 由于我一直试图拼凑一个功能性的示例程序,该程序现在提供带有图标的插件菜单几天,我想我会发布代码,以防它帮助其他任何人. 这是一个功能齐全的示例项目,具有以下功能： >旨在成为包含5个项目的单一解决方案(MainProgram,ContractInterfaces,PlugInA,PlugInB,PlugInC) 我为每个DLL分配了一个不同的Icon(来自旧的Visual Studio 6 Common Graphics Misc文件夹) 从DLL插件中提取图标以创建ListView,并且一旦它们启动(在双击ListView中的每个插件项之后),DLL就会创建文档框并将其发布到GUI. 将以下代码添加到名为“MainProgram”的全新C#WinForm项目中(我使用的是VS 2010)： 由于某种原因,Code Sample解析器不喜欢Using语句,因此它们作为要点： >使用系统; public partial class Form1 : Form
{
// Prerequisites to run:
// 1) Project,Add Reference,Projects,ContractInterface
// 2) Project,.NET,System.ComponentModel.Composition
[ImportMany(typeof(IPlugIn))]
private IEnumerable<Lazy<IPlugIn,IPlugInMetadata>> LoadedPlugIns;
List<PlugInInfo> AvailablePlugIns = null;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender,EventArgs e)
{
// Get a list of the available Plug-Ins
AvailablePlugIns = GetPlugInList();
// Prepare an ImageList to hold the DLL icons
ImageList ImgList = new ImageList();
ImgList.ColorDepth = ColorDepth.Depth32Bit;
ImgList.ImageSize = new Size(32,32);
// Populate ImageList with Plug-In Icons
foreach (var item in AvailablePlugIns)
{
ImgList.Images.Add(item.PlugInIcon.ToBitmap());
}
// Assign the ImageList to the ListView
listView1.LargeImageList = ImgList;
int imageIndex = 0;
// Create the ListView items
foreach (var item in AvailablePlugIns)
{
listView1.Items.Add(item.PlugInTitle,imageIndex);
imageIndex++;
}
listView1.MouseDoubleClick += new MouseEventHandler(listView1_MouseDoubleClick);
}
void listView1_MouseDoubleClick(object sender,MouseEventArgs e)
{
// Get the Plug-In index number
int plugInNum = listView1.SelectedItems[0].Index;
PlugInInfo selectedPlugIn = AvailablePlugIns[plugInNum];
// Call the StartPlugIn method in the selected Plug-In.
// Lazy Instantiation will fully load the Assembly here
selectedPlugIn.PlugIn.StartPlugIn(this);
Console.WriteLine("Plug-In Title: {0}",selectedPlugIn.PlugInTitle);
Console.WriteLine("Plug-In Description: {0}",selectedPlugIn.PlugInDescription);
Console.WriteLine("Plug-In Version: {0}",selectedPlugIn.PlugInVersion);
Console.WriteLine();
}
private List<PlugInInfo> GetPlugInList()
{
// Create a List to hold the info for each plug-in
List<PlugInInfo> plugInList = new List<PlugInInfo>();
// Set Plug-In folder path to same directory level as Solution
string plugInFolderPath = System.IO.Path.Combine(Application.StartupPath,@"......Plug-Ins");
// Test if the Plug-In folder exists
if (!Directory.Exists(plugInFolderPath))
{
// Plug-In Folder is missing,so try to create it
try
{ Directory.CreateDirectory(plugInFolderPath); }
catch
{ MessageBox.Show("Failed to create Plug-In folder","Folder Creation Error:",MessageBoxButtons.OK,MessageBoxIcon.Exclamation); }
}
try
{
// Create a catalog of plug-ins
var catalog = new DirectoryCatalog(plugInFolderPath,"*.dll");
AggregateCatalog plugInCatalog = new AggregateCatalog();
plugInCatalog.Catalogs.Add(catalog);
CompositionContainer container = new CompositionContainer(plugInCatalog);
// This line will fetch the metadata from each plug-in and populate LoadedPlugIns
container.ComposeParts(this);
// Save each Plug-Ins metadata
foreach (var plugin in LoadedPlugIns)
{
PlugInInfo info = new PlugInInfo();
info.PlugInTitle = plugin.Metadata.PlugInTitle;
info.PlugInDescription = plugin.Metadata.PlugInDescription;
info.PlugInVersion = plugin.Metadata.PlugInVersion;
info.PlugIn = plugin.Value;
plugInList.Add(info);
}
int index = 0;
// Extract icons from each Plug-In DLL and store in Plug-In list
foreach (var filePath in catalog.LoadedFiles)
{
plugInList[index].PlugInIcon = Icon.ExtractAssociatedIcon(filePath);
index++;
}
}
catch (FileNotFoundException fex)
{
Console.WriteLine("File not found exception : " + fex.Message);
}
catch (CompositionException cex)
{
Console.WriteLine("Composition exception : " + cex.Message);
}
catch (DirectoryNotFoundException dex)
{
Console.WriteLine("Directory not found exception : " + dex.Message);
}
return plugInList;
}
}
public class PlugInInfo
{
public string PlugInTitle { get; set; }
public string PlugInDescription { get; set; }
public string PlugInVersion { get; set; }
public Icon PlugInIcon { get; set; }
public IPlugIn PlugIn { get; set; }
}
现在将一个名为“listView1”的ListView控件添加到主窗体,并将其保存到窗体的右侧.插件中动态创建的TextBox将显示在左侧. 接下来添加一个名为“ContractInterfaces”的类项目,然后包含以下代码： >使用System.Windows.Forms; // Prerequisites to run:
// 1) Project,"System.Windows.Forms"
public interface IPlugIn
{
void StartPlugIn(Form mainForm);
}
public interface IPlugInMetadata
{
string PlugInTitle { get; }
string PlugInDescription { get; }
string PlugInVersion { get; }
}
接下来添加一个名为“PlugInA”的类项目,然后包含以下代码： >使用系统; // Prerequisites to run:
// 1) Project,"ContractInterface"
// 2) Project,"System.Windows.Forms"
// 3) Project,"System.ComponentModel.Composition"
// 4) Project,Properties,Build Events,Post-Build event command line:
// xcopy "$(ProjectDir)$(OutDir)$(TargetFileName)" "$(SolutionDir)Plug-Ins" /Y
// 5) Project,Run the post-build event:,Always
// 6) Project,Application,Icon and manifest,[Select an icon]
[Export(typeof(IPlugIn))]
[PluginMetadata]
public class Program : IPlugIn
{
private Form MainForm;
public void StartPlugIn(Form mainForm)
{
MainForm = mainForm;
// Place a TextBox on the Main Form
TextBox textBox = new TextBox();
textBox.Text = "PlugInA";
MainForm.Controls.Add(textBox);
textBox.Width = 65;
textBox.Height = 20;
textBox.Top = 0;
textBox.Left = 0;
}
}
// Create a custom strong-typed Metadata Attribute for MEF
[MetadataAttribute]
[AttributeUsage(AttributeTargets.Class,AllowMultiple = false)]
public class PluginMetadataAttribute : ExportAttribute
{
public string PlugInTitle { get; set; }
public string PlugInDescription { get; set; }
public object PlugInVersion { get; set; }
public PluginMetadataAttribute()
: base(typeof(IPlugInMetadata))
{
PlugInTitle = "Plug-In A";
PlugInDescription = "This is Plug-In A";
PlugInVersion = "1.0.0.0";
}
}
接下来添加一个名为“PlugInB”的类项目,然后包含以下代码： >使用系统; // Prerequisites to run:
// 1) Project,[Select an icon]
[Export(typeof(IPlugIn))]
[PluginMetadata]
public class Program : IPlugIn
{
private Form MainForm;
public void StartPlugIn(Form mainForm)
{
MainForm = mainForm;
// Place a TextBox on the Main Form
TextBox textBox = new TextBox();
textBox.Text = "PlugInB";
MainForm.Controls.Add(textBox);
textBox.Width = 65;
textBox.Height = 20;
textBox.Top = 30;
textBox.Left = 0;
}
}
// Create a custom strong-typed Metadata Attribute for MEF
[MetadataAttribute]
[AttributeUsage(AttributeTargets.Class,AllowMultiple = false)]
public class PluginMetadataAttribute : ExportAttribute
{
public string PlugInTitle { get; set; }
public string PlugInDescription { get; set; }
public object PlugInVersion { get; set; }
public PluginMetadataAttribute()
: base(typeof(IPlugInMetadata))
{
PlugInTitle = "Plug-In B";
PlugInDescription = "This is Plug-In B";
PlugInVersion = "1.0.0.1";
}
}
接下来添加一个名为“PlugInC”的类项目,然后包含以下代码： >使用系统; // Prerequisites to run:
// 1) Project,[Select an icon]
[Export(typeof(IPlugIn))]
[PluginMetadata]
public class Program : IPlugIn
{
private Form MainForm;
public void StartPlugIn(Form mainForm)
{
MainForm = mainForm;
// Place a TextBox on the Main Form
TextBox textBox = new TextBox();
textBox.Text = "PlugInC";
MainForm.Controls.Add(textBox);
textBox.Width = 65;
textBox.Height = 20;
textBox.Top = 60;
textBox.Left = 0;
}
}
// Create a custom strong-typed Metadata Attribute for MEF
[MetadataAttribute]
[AttributeUsage(AttributeTargets.Class,AllowMultiple = false)]
public class PluginMetadataAttribute : ExportAttribute
{
public string PlugInTitle { get; set; }
public string PlugInDescription { get; set; }
public object PlugInVersion { get; set; }
public PluginMetadataAttribute()
: base(typeof(IPlugInMetadata))
{
PlugInTitle = "Plug-In C";
PlugInDescription = "This is Plug-In C";
PlugInVersion = "1.0.0.2";
}
}
解决方案应如下所示： 右键单击Solution,然后选择“Project Dependencies …”.设置依赖项如下： > MainProgram – 取决于 – ContractInterface 右键单击解决方案,然后选择“项目构建顺序…”.构建顺序应如下所示： > ContractInterface 构建并运行该程序.您应该看到3个DLL文件被复制到与解决方案文件(* .sln)相同的目录级别的新“Plug-Ins”文件夹中.如果没有,请检查项目构建顺序,依赖项,以及您是否根据上面插件代码中的注释输入了构建后事件.如果文件在那里,则应在带有插件条目的表单中填充ListView.双击每个ListView条目以启动插件. 玩得开心,我希望这有助于某人…. （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |