C# – .NET Load assemblies at runtime Again

assembliescnetreflection

I posted a similar question a time ago. I need to load an assembly at runtime.

This is easy if I know the absolute path of the dll at runtime.

But I dont 🙁 The assembly.Load() or LoadFromFile() fails if the file is not in the application root.

The only thing I have is the dll name. The dll could be located in the root, system32 or in even in the GAC.

Is it possible for .net to automatically determine where the dll is at, like for example :
it should first look in the root. If its not there move on to the system folders, else try the GAC.

EDITED

I am using plug-in architecture. I do not need to register the dll. I have a multi user application. I have a applications table containing information regarding applications. Each application has a dll path associated with it, containing certain algorithms associated with that app. Hope this helps.

Best Answer

When the current application looks for assemblies, it looks in several locations (bin folder, gac, etc..) if it can not find one, then the developer needs to manually tell the application where to look. You can do this by intercepting the AssemblyResolve event, and using the event args to tell the CLR where your assembly is.

AppDomain.CurrentDomain.AssemblyResolve += CurrentDomain_AssemblyResolve;
....................
Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
{
   var strTempAssmbPath=
          Path.GetFullPath("C:\\Windows\\System32\\" + args.Name.Substring(0,  args.Name.IndexOf(",")) + ".dll");

   var strTempAssmbPath2=
          Path.GetFullPath("C:\\Windows\\" + args.Name.Substring(0,  args.Name.IndexOf(",")) + ".dll");


    if (File.Exists(strTempAssmbPath))
            return Assembly.LoadFrom(strTempAssmbPath);

    if (File.Exists(strTempAssmbPath2))
            return Assembly.LoadFrom(strTempAssmbPath2);
}

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C# – Sending email in .NET through Gmail

Be sure to use System.Net.Mail, not the deprecated System.Web.Mail. Doing SSL with System.Web.Mail is a gross mess of hacky extensions.

using System.Net;
using System.Net.Mail;

var fromAddress = new MailAddress("from@gmail.com", "From Name");
var toAddress = new MailAddress("to@example.com", "To Name");
const string fromPassword = "fromPassword";
const string subject = "Subject";
const string body = "Body";

var smtp = new SmtpClient
{
    Host = "smtp.gmail.com",
    Port = 587,
    EnableSsl = true,
    DeliveryMethod = SmtpDeliveryMethod.Network,
    UseDefaultCredentials = false,
    Credentials = new NetworkCredential(fromAddress.Address, fromPassword)
};
using (var message = new MailMessage(fromAddress, toAddress)
{
    Subject = subject,
    Body = body
})
{
    smtp.Send(message);
}

Additionally go to the Google Account > Security page and look at the Signing in to Google > 2-Step Verification setting.

If it is enabled, then you have to generate a password allowing .NET to bypass the 2-Step Verification. To do this, click on Signing in to Google > App passwords, select app = Mail, and device = Windows Computer, and finally generate the password. Use the generated password in the fromPassword constant instead of your standard Gmail password.
If it is disabled, then you have to turn on Less secure app access, which is not recommended! So better enable the 2-Step verification.

C# – How to get the path of the assembly the code is in

I've defined the following property as we use this often in unit testing.

public static string AssemblyDirectory
{
    get
    {
        string codeBase = Assembly.GetExecutingAssembly().CodeBase;
        UriBuilder uri = new UriBuilder(codeBase);
        string path = Uri.UnescapeDataString(uri.Path);
        return Path.GetDirectoryName(path);
    }
}

The Assembly.Location property sometimes gives you some funny results when using NUnit (where assemblies run from a temporary folder), so I prefer to use CodeBase which gives you the path in URI format, then UriBuild.UnescapeDataString removes the File:// at the beginning, and GetDirectoryName changes it to the normal windows format.

Best Answer

Related Solutions

C# – Sending email in .NET through Gmail

C# – How to get the path of the assembly the code is in

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