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PONeed to resolve HMONITOR --> deviceName (or deviceName --> HMONITOR) in windows
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copied!<p><strong>EDIT</strong> - See Update at end </p> <p>This is for Delphi 7.0 Build 4.453</p> <p><strong>Summary</strong></p> <p>I need to be able to take the Handle property from a TMonitor object (an element in the Monitors array in the TScreen component) which is a HMONITOR, and turn it into the string you would use in calls to <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/dd162611%28v=vs.85%29.aspx" rel="nofollow">EnumDisplaySettings</a> as the lpszDeviceName parameter.</p> <p>(my end goal is to get a list of device settings from a given HMONITOR value, by passing the resolved lpszDeviceName into calls to EnumDisplaySettings).</p> <p><strong>Detailed Information</strong></p> <p>As mentioned above, the Screen.Monitors[x].Handle property is of type HMONITOR and is normally used to pass into the <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/dd144901%28v=vs.85%29.aspx" rel="nofollow">GetMonitorInfo</a> function, which returns, geometry information, but no lpszDeviceName. (note: there is a <a href="http://msdn.microsoft.com/en-us/library/windows/desktop/dd145066%28v=vs.85%29.aspx" rel="nofollow">TMonitorInfoEx</a> structure that has a szDevice field, but it does not seem to get filled in on my system, even though i am setting the cbSize field to the appropriate size).</p> <p><strong>Alternatively</strong>, if i can use a szDeviceName to get the equivalent HMONITOR value, i could plug it into the following function, which would use it in a comparison (I have inserted a call to fictitious function called <strong>hMonitorFromDeviceName</strong> in the code below) to indicate how it would be used. </p> <pre><code>function GetMonitorDeviceName(hmon : HMONITOR) : string; var DispDev : TDisplayDevice; deviceName : string; nDeviceIndex : integer; begin Result := ''; FillChar(DispDev, sizeof(DispDev),0); DispDev.cb := sizeof(DispDev); nDeviceIndex := 0; while (EnumDisplayDevices(nil, nDeviceIndex, DispDev, 0)) do begin if ( hMonitorFromDeviceName(DispDev.DeviceString) = hmon ) then begin Result := StrPas(DispDev.DeviceString); exit; end; inc(nDeviceIndex); end; end; </code></pre> <p><strong>Update</strong></p> <p>Thanks to David Heffernan, I have tested his solution, and here is a sample function to get the monitor name from a given handle:</p> <pre><code>function GetMonitorName(hmon : HMONITOR) : string; type TMonitorInfoEx = record cbSize: DWORD; rcMonitor: TRect; rcWork: TRect; dwFlags: DWORD; szDevice: array[0..CCHDEVICENAME - 1] of AnsiChar; end; var DispDev : TDisplayDevice; deviceName : string; monInfo : TMonitorInfoEx; begin Result := ''; monInfo.cbSize := sizeof(monInfo); if GetMonitorInfo(hmon,@monInfo) then begin DispDev.cb := sizeof(DispDev); EnumDisplayDevices(@monInfo.szDevice, 0, DispDev, 0); Result := StrPas(DispDev.DeviceString); end; end; </code></pre>

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