How to read “uSNChanged” property using C#

问题

I want to get the last modified or created attributes via the uSNChanged value in ActiveDirectory using C# ... I was also trying to find the max value of uSNChanged, can you help me to find out the solution? Thanks

回答1:

There are two ways to retrieve the uSNChanged property via .NET:

Include a reference to a COM library: "Active DS Type Library", then you need to use the IADsLargeInterger to retrieve the value and finally convert it to a long. For example:

IADsLargeInteger li_ad = (IADsLargeInteger)oUser.Properties["USNChanged"].Value;
long l_uChanged = GetLongFromLargeInteger( li_ad );

static long GetLongFromLargeInteger(  IADsLargeInteger  Li )
{
    long retval = Li.HighPart;
    retval <<=32;
    retval |=(uint)Li.LowPart;
    return retval;
}

Translate the values only using C#. Thanks to Simon Gilbee, we have this option:

long usnChanged = CovertADSLargeIntegerToInt64(oUser.Properties["USNChanged"].Value);

public static Int64 ConvertADSLargeIntegerToInt64(object adsLargeInteger)
{
  var highPart = (Int32)adsLargeInteger.GetType().InvokeMember("HighPart", System.Reflection.BindingFlags.GetProperty, null, adsLargeInteger, null);
  var lowPart  = (Int32)adsLargeInteger.GetType().InvokeMember("LowPart",  System.Reflection.BindingFlags.GetProperty, null, adsLargeInteger, null);
  return highPart * ((Int64)UInt32.MaxValue + 1) + lowPart;
}

I highly recommend you go with Option #2 to avoid problems with the legacy ActiveDs library and won't need answers off this list.

回答2:

i got the solution guys,we can get a maximum usnchanged value of a domaincontroller through this attribute HighestCommittedUsn

来源：https://stackoverflow.com/questions/10958278/how-to-read-usnchanged-property-using-c-sharp

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active-directory

directoryservices