Add in C#-based method to retrieve total system memory as part of CIM code removal.

Author: mjr4077au

src/PSADT/PSADT.Interop/NativeMethods.cs

@@ -3757,6 +3757,24 @@ internal static WIN32_ERROR NetGetJoinInformation(out SafeNetApiBufferFreeHandle
             return NetGetJoinInformation(null, out lpNameBuffer, out BufferType);
         }
 
+        /// <summary>
+        /// Retrieves information about the system's current usage of both physical and virtual memory.
+        /// </summary>
+        /// <remarks>This method wraps the native GlobalMemoryStatusEx function. The output parameter must
+        /// not be used until the method returns successfully. If the call fails, an exception is thrown.</remarks>
+        /// <param name="lpBuffer">When this method returns, contains a structure that receives information about current memory availability.
+        /// The structure's fields are populated with memory status data.</param>
+        /// <returns>true if the memory status information was successfully retrieved; otherwise, false.</returns>
+        internal static BOOL GlobalMemoryStatusEx(out MEMORYSTATUSEX lpBuffer)
+        {
+            lpBuffer = new MEMORYSTATUSEX
+            {
+                dwLength = (uint)Marshal.SizeOf<MEMORYSTATUSEX>()
+            };
+            BOOL res = PInvoke.GlobalMemoryStatusEx(ref lpBuffer);
+            return !res ? throw ExceptionUtilities.GetExceptionForLastWin32Error() : res;
+        }
+
         /// <summary>
         /// Lookup table for system information class struct sizes.
         /// </summary>

src/PSADT/PSADT.Interop/NativeMethods.txt

@@ -66,6 +66,7 @@ GetTokenInformation
 GetWindowText
 GetWindowTextLength
 GetWindowThreadProcessId
+GlobalMemoryStatusEx
 HIWORD
 HKEY_CLASSES_ROOT
 HKEY_CURRENT_CONFIG

src/PSADT/PSADT/DeviceManagement/DeviceUtilities.cs

@@ -8,6 +8,7 @@
 using Windows.Win32.Foundation;
 using Windows.Win32.Media.Audio;
 using Windows.Win32.System.Com;
+using Windows.Win32.System.SystemInformation;
 
 namespace PSADT.DeviceManagement
 {
@@ -143,5 +144,15 @@ public static DomainStatus GetDomainStatus()
                 return new((NETSETUP_JOIN_STATUS)bufferType, nameBuffer.ToStringUni());
             }
         }
+
+        /// <summary>
+        /// Retrieves the total amount of physical memory installed on the system, in bytes.
+        /// </summary>
+        /// <returns>The total physical memory, in bytes, available on the system.</returns>
+        public static ulong GetTotalSystemMemory()
+        {
+            _ = NativeMethods.GlobalMemoryStatusEx(out MEMORYSTATUSEX lpBuffer);
+            return lpBuffer.ullTotalPhys;
+        }
     }
 }