.net 动态加载Dll - icyjiang - 博客园

来源： .net 动态加载Dll – icyjiang – 博客园

在程序正在使用的过程中，常常需要升级DLL。这时，如果dll已经被主程序引用，则无法修改，这样的需求应该很常见。换个角度，可以理解成程序的升级或者修改Bug的功能。

以下通过动态的加载Dll来解决这个问题。

整个思路的前提是，动态调用的东西和前台需要的功能通过代理IBaseInterface连接起来，也就是说动态dll里面的类和Proxy都需要实现这个接口。

namespace BaseInterface
{
public interface IBaseInterface
{
string GetString();
}
}

核心代码：Proxy.dll

<pre>namespace Proxy
{
    internal class AppDomainCore
    {
        public AppDomain DefaultAppDomain { get; private set; }
        public string DefaultAppDomainName { get; private set; }

        public AppDomainCore(string appDomainName)
        {
            DefaultAppDomainName = appDomainName;
            AppDomainSetup setup = new AppDomainSetup();
            setup.ApplicationBase = AppDomain.CurrentDomain.BaseDirectory;
            setup.ConfigurationFile = AppDomain.CurrentDomain.SetupInformation.ConfigurationFile;

            Evidence evidence = new Evidence(AppDomain.CurrentDomain.Evidence);
            DefaultAppDomain = AppDomain.CreateDomain(appDomainName, evidence, setup);
        }

        public bool ClearAppDomain()
        {
            try
            {
                AppDomain.Unload(DefaultAppDomain);
                DefaultAppDomain = null;
                return true;
            }
            catch { return false; }
        }

        ~AppDomainCore()
        {
            ClearAppDomain();
        }
    }
}</pre>
<div class="cnblogs_code_toolbar"><span class="cnblogs_code_copy"><a title="复制代码"><img src="http://www.mikel.cn/wp-content/uploads/2015/05/copycode30.gif" alt="复制代码" data-bd-imgshare-binded="1" /></a></span>namespace Proxy
{
internal class AssemblyCore
{
public string ActivedAssemblyName { get; private set; }
public string CurrentType { get; private set; }
public FileInfo DefaultAssemblyFile { get; private set; }

public AssemblyCore(string assemblyName, string type)
{
ActivedAssemblyName = assemblyName;
CurrentType = type;

try
{
DefaultAssemblyFile = new FileInfo(assemblyName);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
}</div>
<div class="cnblogs_code_toolbar"></div>
<div class="cnblogs_code_toolbar">namespace Proxy
{
public class Proxy : BaseInterface.IBaseInterface
{
AssemblyCore _assemblyCore;
AppDomainCore _appDomainCore;

public string DefaultAssemblyName { get { return _assemblyCore.ActivedAssemblyName; } }
public string DefaultAppDomainName { get { return _appDomainCore.DefaultAppDomainName; } }

public Proxy(string assemblyName, string typeName, string appDomainName)
{
_assemblyCore = new AssemblyCore(assemblyName, typeName);
_appDomainCore = new AppDomainCore(appDomainName);
}

public void UnLoad()
{
_appDomainCore.ClearAppDomain();
}

BaseInterface.IBaseInterface _proxy;
public string GetString()
{
if (_proxy == null)
_proxy = _appDomainCore.DefaultAppDomain.CreateInstanceFromAndUnwrap(
_assemblyCore.ActivedAssemblyName, _assemblyCore.CurrentType)
as BaseInterface.IBaseInterface;
return _proxy.GetString();
}
}
}</div>
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