fix MsRdpEx init code and add logging

src/RoyalApps.Community.Rdp.WinForms/Configuration/RdpClientConfiguration.cs

@@ -1,20 +1,12 @@
-namespace RoyalApps.Community.Rdp.WinForms.Configuration;
+using System;
+
+namespace RoyalApps.Community.Rdp.WinForms.Configuration;
 
 /// <summary>
 /// The remote desktop client configuration.
 /// </summary>
 public class RdpClientConfiguration
 {
-    /// <summary>
-    /// The client version to use. By default (value is 0) the highest available client will be used.
-    /// </summary>
-    public int ClientVersion { get; set; }
-
-    /// <summary>
-    /// If true, Microsoft's Remote Desktop Client is used (when installed) instead of the legacy MSTSC ActiveX control.
-    /// </summary>
-    public bool UseMsRdc { get; set; }
-
     /// <summary>
     /// Specifies the name of the server to which the current control is connected.
     /// The new server name. This parameter can be a DNS name or IP address.
@@ -33,6 +25,11 @@ public class RdpClientConfiguration
     /// </seealso>
     public int Port { get; set; } = 3389;
 
+    /// <summary>
+    /// The client version to use. By default (value is 0) the highest available client will be used.
+    /// </summary>
+    public int ClientVersion { get; set; }
+
     /// <summary>
     /// Specifies the names of virtual channel client DLLs to be loaded. Virtual channel client DLLs are also referred to as Plug-in DLLs.
     /// Comma-separated list of the names of the virtual channel client DLLs to be loaded. The DLL names must contain only alphanumeric characters.
@@ -41,6 +38,31 @@ public class RdpClientConfiguration
     ///     <cref>https://docs.microsoft.com/en-us/windows/win32/termserv/imstscadvancedsettings-plugindlls</cref>
     /// </seealso>
     public string? PluginDlls { get; set; }
+
+    /// <summary>
+    /// If true, Microsoft's Remote Desktop Client is used (when installed) instead of the legacy MSTSC ActiveX control.
+    /// </summary>
+    public bool UseMsRdc { get; set; }
+
+    /// <summary>
+    /// If set, the Microsoft Remote Desktop Client files (rdclientax.dll) will be searched here at first.
+    /// </summary>
+    public string? MsRdcPath { get; set; }
+
+    /// <summary>
+    /// If true, a detailed log file will be written to the file system (see: LogFilePath)
+    /// </summary>
+    public bool LogEnabled { get; set; }
+
+    /// <summary>
+    /// The following log levels are available: TRACE, DEBUG, INFO, WARN, ERROR, FATAL, OFF
+    /// </summary>
+    public string LogLevel { get; set; } = "TRACE";
+
+    /// <summary>
+    /// The file path to the log file when LogEnabled is set to true.
+    /// </summary>
+    public string LogFilePath { get; set; } = Environment.ExpandEnvironmentVariables(@"%TEMP%\MsRdpEx.log");
 
     /// <summary>
     /// The credential configuration used to log on to the remote desktop session.

src/RoyalApps.Community.Rdp.WinForms/Controls/RdpControl.cs

@@ -35,13 +35,13 @@ public class RdpControl : UserControl
     private Size _previousClientSize = Size.Empty;
 
     private readonly Timer _timerResizeInProgress;
-    private readonly HashSet<string> _rdClientSearchPaths = new()
-    {
+    private readonly HashSet<string> _rdClientSearchPaths =
+    [
         @"%ProgramFiles%\Remote Desktop",
         @"%ProgramFiles(x86)%\Remote Desktop",
         @"%ProgramFiles(ARM)%\Remote Desktop",
         @"%LocalAppData%\Apps\Remote Desktop"
-    };
+    ];
 
     /// <summary>
     /// Access to the RDP client and their events, methods and properties.
@@ -541,6 +541,10 @@ private void CreateRdpClient()
     {
         RdpClient = RdpClientFactory.Create(RdpConfiguration.ClientVersion);
 
+        Environment.SetEnvironmentVariable("MSRDPEX_LOG_ENABLED", RdpConfiguration.LogEnabled ? "1" : "0");
+        Environment.SetEnvironmentVariable("MSRDPEX_LOG_LEVEL", RdpConfiguration.LogLevel);
+        Environment.SetEnvironmentVariable("MSRDPEX_LOG_FILE_PATH", RdpConfiguration.LogFilePath);
+
         var control = (Control) RdpClient;
         control.Dock = DockStyle.Fill;
         Controls.Add(control);
@@ -550,14 +554,21 @@ private void CreateRdpClient()
         if (RdpConfiguration.UseMsRdc)
         {
             string? msRdcAxLibrary = null;
-            foreach (var path in _rdClientSearchPaths)
+
+            if (!string.IsNullOrWhiteSpace(RdpConfiguration.MsRdcPath) && File.Exists(RdpConfiguration.MsRdcPath))
+                msRdcAxLibrary = RdpConfiguration.MsRdcPath;
+
+            if (string.IsNullOrWhiteSpace(msRdcAxLibrary))
             {
-                var searchPath = Path.Combine(Environment.ExpandEnvironmentVariables(path), "rdclientax.dll");
-                Logger.LogDebug("Searching file {SearchPath}", searchPath);
-                if (!Path.Exists(searchPath))
-                    continue;
-                msRdcAxLibrary = searchPath;
-                break;
+                foreach (var path in _rdClientSearchPaths)
+                {
+                    var searchPath = Path.Combine(Environment.ExpandEnvironmentVariables(path), "rdclientax.dll");
+                    Logger.LogDebug("Searching file {SearchPath}", searchPath);
+                    if (!Path.Exists(searchPath))
+                        continue;
+                    msRdcAxLibrary = searchPath;
+                    break;
+                }
             }
 
             if (string.IsNullOrWhiteSpace(msRdcAxLibrary))
@@ -568,6 +579,7 @@ private void CreateRdpClient()
             else
             {
                 Environment.SetEnvironmentVariable("MSRDPEX_RDCLIENTAX_DLL", msRdcAxLibrary);
+                Environment.SetEnvironmentVariable("MSRDPEX_AXNAME", "msrdc");
                 Logger.LogInformation("Microsoft Remote Desktop Client will be used");
 
                 RdpClient.AxName = "msrdc";