如何連續F＃WMI類提供商

嗨，我嘗試了F＃WMI類提供商的代碼示例獲取計數器值看起來像這樣如何連續F＃WMI類提供商

type Local = WmiProvider<"localhost"> 
let data = Local.GetDataContext() 
let memory = [for d in data.Win32_PerfFormattedData_PerfOS_Memory -> d.AvailableBytes]

內存在這種情況下是System.Nullable名單。所以問題是如何獲得這個列表的連續更新？目前我的代碼看起來像這樣

let printMemory() = 
    let rec outerLoop = 
     let memory = [for d in data.Win32_PerfFormattedData_PerfOS_Memory -> d.AvailableBytes] 
     let rec loop (values:Nullable<uint64> list) = 
      Thread.Sleep(1000) 
      match values with 
      |[] -> printfn "empty" 
        outerLoop 
      |h::t -> printfn "value = %d" h.Value 
        loop t 
     loop memory 
    outerLoop

所以，我必須請求新的列表（記憶）每一次，這是正確的做法？例如System.Diagnostics的PerformanceCounter計數器實現NextValue，是否有類似WMI類型提供程序的東西？謝謝！

來源

2016-09-22 Maxim Podkolzin

如果您不希望阻止當前線程，Rx提供用於處理一個很好的API：

// nuget FSharp.Management 
#I "packages/FSharp.Management/lib/net40" 
// nuget System.Reactive 
#I "packages/System.Reactive.Core/lib/net46" 
#I "packages/System.Reactive.Linq/lib/net46" 
#I "packages/System.Reactive.Interfaces/lib/net45" 

#r "System.Management.dll" 
#r "FSharp.Management.WMI.dll" 
#r "System.Reactive.Core.dll" 
#r "System.Reactive.Interfaces.dll" 
#r "System.Reactive.Linq.dll" 

open FSharp.Management 
open System 
open System.Reactive.Linq 
open System.Runtime.InteropServices 
open System.Text 

[<DllImport("shlwapi.dll", CharSet = CharSet.Unicode)>] 
extern int64 StrFormatKBSize(int64 qdw, [<MarshalAs(UnmanagedType.LPTStr)>] StringBuilder pszBuf, int cchBuf); 

let bytesToString byteCount = 
    let sb = StringBuilder(32); 
    StrFormatKBSize(byteCount, sb, sb.Capacity) |> ignore 
    sb.ToString() 

type Local = WmiProvider<"localhost"> 
let memory = Local.GetDataContext().Win32_PerfFormattedData_PerfOS_Memory 
let freeMem() = 
    // I don't know the semantics of Win32_PerfFormattedData_PerfOS_Memory 
    // you might want to adjust the following 
    memory 
    |> Seq.choose (fun d -> d.AvailableBytes |> Option.ofNullable) 
    |> Seq.exactlyOne 

let print m = 
    printfn "At %A: free %s" DateTime.UtcNow (bytesToString(int64 m)) 

// Immediately start to produce values every 1 second (on thread pool) 
Observable.Timer(TimeSpan.Zero, TimeSpan.FromSeconds 1.0) 
|> Observable.map(fun _ -> freeMem()) 
// only propagate a value if it differs from the previous one 
|> Observable.DistinctUntilChanged 
|> Observable.subscribe print 

// Causes a non-fatal error in VS Interactive, works in FSI 
Console.ReadKey() |> ignore

該腳本產生例如

在2016年9月27日10點24分10秒：免費8'053'600 KB
在2016年9月27日10:24:11：免費8'053'604 KB
在2016年9月27日10： 24:13：免費8'053'600 KB
At at 27.09.2016 10:24:14：free 8'053'604 KB
At 27.09.2016 10:24:15：free 8'054'472 KB
At 27.09.2016 10:24:16：free 8'054'468 KB
At at 27.09.2016 10:24:17：free 8'054'496 KB
At 27.09.2016 10:24:18：free 8'054'480 KB
At 27.09.2016 10:24:20：free 8'054'492 KB

來源

2016-09-27 10:26:47 CaringDev

你將不得不作出的調用明確新的值，或使用刷新對象WmiSmoObject.Refresh

F# 
abstract Refresh : unit -> unit 
override Refresh : unit -> unit

來源

2016-09-23 17:19:34

WmiSmoObject是Microsoft.SqlServer.Management的一部分，我不想監視它。我已經明確要求更新每個掃描週期，只是想知道是否可以更新 –

如何連續F＃WMI類提供商

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