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need help calling an external function within c#

Posted on 2016-09-29
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Last Modified: 2016-09-29
hi.

regarding MS article:   https://msdn.microsoft.com/en-us/windows/hardware/drivers/install/retrieving-a-device-instance-property-value

i am attempting to call setupDiGetDeviceProperty:

            [DllImport("setupapi.dll", SetLastError = true)]
            static extern bool SetupDiGetDevicePropertyW(
                    IntPtr deviceInfoSet,
                    [In] ref SP_DEVINFO_DATA DeviceInfoData,
                    [In] ref DEVPROPKEY propertyKey,
                    [Out] out UInt32 propertyType,
                    IntPtr propertyBuffer,
                    UInt32 propertyBufferSize,
                    out UInt32 requiredSize,
                    UInt32 flags);

when i call it the first time, the requiredSize is being returned fine.  when i call the function for a second time, i receive error code 1784:
ERROR_INVALID_USER_BUFFER
    1784
    The supplied user buffer is not valid for the requested operation

i'm using this the second time:

SetupDiGetDevicePropertyW(info, ref devdata, ref devprop, out proptype, propertyBuffer, requiredSize, out temp, 0)

i don't know what to send the function for the propertyBuffer.... will you please help?

thank you.
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Question by:freezingHot
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freezingHot earned 0 total points
ID: 41822650
ended up using a byte array and it worked...
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