Getting a list of DLLs currently loaded in a process C#

There exists the Process.Modules property which you can enumerate all Modules (exe and .dll's) loaded by the process.

foreach (var module in proc.Modules)
{
   Console.WriteLine(string.Format("Module: {0}", module.FileName));
}

Per the ProcessModule class which gives you the properties of a specific module.

The Process.Modules solution is NOT sufficient when running a 64-bit program and trying to collect all modules from a 32-bit process. By default, a 64-bit program will only work on a 64-bit process, and a 32-bit program will only work on a 32-bit processes.

For a solution that works for "AnyCPU", "x86", and "x64", see below. Simply call the CollectModules function with the target process. Note: A 32-bit program cannot collect modules from a 64-bit process.

public List<Module> CollectModules(Process process)
{
        List<Module> collectedModules = new List<Module>();

        IntPtr[] modulePointers = new IntPtr[0];
        int bytesNeeded = 0;

        // Determine number of modules
        if (!Native.EnumProcessModulesEx(process.Handle, modulePointers, 0, out bytesNeeded, (uint)Native.ModuleFilter.ListModulesAll))
        {
            return collectedModules;
        }

        int totalNumberofModules = bytesNeeded / IntPtr.Size;
        modulePointers = new IntPtr[totalNumberofModules];

        // Collect modules from the process
        if (Native.EnumProcessModulesEx(process.Handle, modulePointers, bytesNeeded, out bytesNeeded, (uint)Native.ModuleFilter.ListModulesAll))
        {
            for (int index = 0; index < totalNumberofModules; index++)
            {
                StringBuilder moduleFilePath = new StringBuilder(1024);
                Native.GetModuleFileNameEx(process.Handle, modulePointers[index], moduleFilePath, (uint)(moduleFilePath.Capacity));

                string moduleName = Path.GetFileName(moduleFilePath.ToString());
                Native.ModuleInformation moduleInformation = new Native.ModuleInformation();
                Native.GetModuleInformation(process.Handle, modulePointers[index], out moduleInformation, (uint)(IntPtr.Size * (modulePointers.Length)));

                // Convert to a normalized module and add it to our list
                Module module = new Module(moduleName, moduleInformation.lpBaseOfDll, moduleInformation.SizeOfImage);
                collectedModules.Add(module);
            }
        }

        return collectedModules;
    }
}

public class Native
{
    [StructLayout(LayoutKind.Sequential)]
    public struct ModuleInformation
    {
        public IntPtr lpBaseOfDll;
        public uint SizeOfImage;
        public IntPtr EntryPoint;
    }

    internal enum ModuleFilter
    {
        ListModulesDefault = 0x0,
        ListModules32Bit = 0x01,
        ListModules64Bit = 0x02,
        ListModulesAll = 0x03,
    }

    [DllImport("psapi.dll")]
    public static extern bool EnumProcessModulesEx(IntPtr hProcess, [MarshalAs(UnmanagedType.LPArray, ArraySubType = UnmanagedType.U4)] [In][Out] IntPtr[] lphModule, int cb, [MarshalAs(UnmanagedType.U4)] out int lpcbNeeded, uint dwFilterFlag);

    [DllImport("psapi.dll")]
    public static extern uint GetModuleFileNameEx(IntPtr hProcess, IntPtr hModule, [Out] StringBuilder lpBaseName, [In] [MarshalAs(UnmanagedType.U4)] uint nSize);

    [DllImport("psapi.dll", SetLastError = true)]
    public static extern bool GetModuleInformation(IntPtr hProcess, IntPtr hModule, out ModuleInformation lpmodinfo, uint cb);
}

public class Module
{
    public Module(string moduleName, IntPtr baseAddress, uint size)
    {
        this.ModuleName = moduleName;
        this.BaseAddress = baseAddress;
        this.Size = size;
    }

    public string ModuleName { get; set; }
    public IntPtr BaseAddress { get; set; }
    public uint Size { get; set; }
}

This depends on what you want precisely.

Getting the list of .NET assemblies loaded into a specific app domain is easy (AppDomain.GetAssemblies).

But listing the App Domains in a process isn't so easy but can be done.

However if you want a list of dll's – native and .NET – as Tony the Lion answers, is just Process.Modules.