=====文件名：Get-TimedScreenshot.ps1=====
function Get-TimedScreenshot {
<#
    Author:fuhj(powershell#live.cn ,http://fuhaijun.com)
    Takes screenshots at a regular interval and saves them to disk.
.PARAMETER Path
    Specifies the folder path.
.PARAMETER Interval
    Specifies the interval in seconds between taking screenshots.
.Parameter EndTime
    Specifies when the script should stop running in the format HH-MM
.Example
    Get-TimedScreenshot -Path c:\temp\ -Interval 30 -EndTime 14:00
#>

    [CmdletBinding()] Param(
        [Parameter(Mandatory=$True)]
        [ValidateScript({Test-Path -Path $_ })]
        [String] $Path,

        [Parameter(Mandatory=$True)]
        [Int32] $Interval,

        [Parameter(Mandatory=$True)]
        [String] $EndTime
    )

    #Define helper function that generates and saves screenshot
    Function Get-Screenshot {
       $ScreenBounds = [Windows.Forms.SystemInformation]::VirtualScreen
       $ScreenshotObject = New-Object Drawing.Bitmap $ScreenBounds.Width, $ScreenBounds.Height
       $DrawingGraphics = [Drawing.Graphics]::FromImage($ScreenshotObject)
       $DrawingGraphics.CopyFromScreen( $ScreenBounds.Location, [Drawing.Point]::Empty, $ScreenBounds.Size)
       $DrawingGraphics.Dispose()
       $ScreenshotObject.Save($FilePath)
       $ScreenshotObject.Dispose()
    }
    Try {

        #load required assembly
        Add-Type -Assembly System.Windows.Forms           

        Do {
            #get the current time and build the filename from it
            $Time = (Get-Date)

            [String] $FileName = "$($Time.Month)"
            $FileName += '-'
            $FileName += "$($Time.Day)"
            $FileName += '-'
            $FileName += "$($Time.Year)"
            $FileName += '-'
            $FileName += "$($Time.Hour)"
            $FileName += '-'
            $FileName += "$($Time.Minute)"
            $FileName += '-'
            $FileName += "$($Time.Second)"
            $FileName += '.png'

            #use join-path to add path to filename
            [String] $FilePath = (Join-Path $Path $FileName)

            #run screenshot function
            Get-Screenshot

            Write-Verbose "Saved screenshot to $FilePath. Sleeping for $Interval seconds"

            Start-Sleep -Seconds $Interval
        }

        #note that this will run once regardless if the specified time as passed
        While ((Get-Date -Format HH:mm) -lt $EndTime)
    }

    Catch {Write-Error $Error[0].ToString() + $Error[0].InvocationInfo.PositionMessage}
}