1+ using System ;
2+ using System . Messaging ;
3+ using System . Runtime . InteropServices ;
4+
5+ static class MsmqExtensions
6+ {
7+ /// <remarks>
8+ /// Source: http://functionalflow.co.uk/blog/2008/08/27/counting-the-number-of-messages-in-a-message-queue-in/
9+ /// </remarks>
10+ public static int GetCount ( this MessageQueue self )
11+ {
12+ var props = new Win32 . MQMGMTPROPS { cProp = 1 } ;
13+ try
14+ {
15+ props . aPropID = Marshal . AllocHGlobal ( sizeof ( int ) ) ;
16+ Marshal . WriteInt32 ( props . aPropID , Win32 . PROPID_MGMT_QUEUE_MESSAGE_COUNT ) ;
17+
18+ props . aPropVar = Marshal . AllocHGlobal ( Marshal . SizeOf ( typeof ( Win32 . MQPROPVariant ) ) ) ;
19+ Marshal . StructureToPtr ( new Win32 . MQPROPVariant { vt = Win32 . VT_NULL } , props . aPropVar , false ) ;
20+
21+ props . status = Marshal . AllocHGlobal ( sizeof ( int ) ) ;
22+ Marshal . WriteInt32 ( props . status , 0 ) ;
23+
24+ var result = Win32 . MQMgmtGetInfo ( null , "queue=" + self . FormatName , ref props ) ;
25+ if ( result != 0 )
26+ {
27+ throw new InvalidOperationException ( $ "Unable to retrieve queue information (error: { result : x8} ") ;
28+ }
29+
30+ if ( Marshal . ReadInt32 ( props . status ) != 0 )
31+ {
32+ return - 1 ;
33+ }
34+
35+ var propVar = ( Win32 . MQPROPVariant ) Marshal . PtrToStructure ( props . aPropVar , typeof ( Win32 . MQPROPVariant ) ) ;
36+
37+ return propVar . vt != Win32 . VT_UI4
38+ ? 0
39+ : Convert . ToInt32 ( propVar . ulVal ) ;
40+ }
41+ finally
42+ {
43+ Marshal . FreeHGlobal ( props . aPropID ) ;
44+ Marshal . FreeHGlobal ( props . aPropVar ) ;
45+ Marshal . FreeHGlobal ( props . status ) ;
46+ }
47+ }
48+
49+ static class Win32
50+ {
51+ [ DllImport ( "mqrt.dll" ) ]
52+ internal static extern uint MQMgmtGetInfo ( [ MarshalAs ( UnmanagedType . BStr ) ] string computerName , [ MarshalAs ( UnmanagedType . BStr ) ] string objectName , ref MQMGMTPROPS mgmtProps ) ;
53+
54+ public const byte VT_NULL = 1 ;
55+ public const byte VT_UI4 = 19 ;
56+ public const int PROPID_MGMT_QUEUE_MESSAGE_COUNT = 7 ;
57+
58+ //size must be 16
59+ [ StructLayout ( LayoutKind . Sequential ) ]
60+ internal struct MQPROPVariant
61+ {
62+ public byte vt ; //0
63+ public byte spacer ; //1
64+ public short spacer2 ; //2
65+ public int spacer3 ; //4
66+ public uint ulVal ; //8
67+ public int spacer4 ; //12
68+ }
69+
70+ //size must be 16 in x86 and 28 in x64
71+ [ StructLayout ( LayoutKind . Sequential ) ]
72+ internal struct MQMGMTPROPS
73+ {
74+ public uint cProp ;
75+ public IntPtr aPropID ;
76+ public IntPtr aPropVar ;
77+ public IntPtr status ;
78+ }
79+ }
80+ }
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