Utility PowerShell function that facilitates the loading of specific properties of a Microsoft.SharePoint.Client.ClientObject object or Microsoft.SharePoint.Client.ClientObjectCollection object.

Load-CSOMProperties.psm1

<#
.Synopsis
    Facilitates the loading of specific properties of a Microsoft.SharePoint.Client.ClientObject object or Microsoft.SharePoint.Client.ClientObjectCollection object.
.DESCRIPTION
    Replicates what you would do with a lambda expression in C#. 
    For example, "ctx.Load(list, l => list.Title, l => list.Id)" becomes
    "Load-CSOMProperties -object $list -propertyNames @('Title', 'Id')".
.EXAMPLE
    Load-CSOMProperties -parentObject $web -collectionObject $web.Fields -propertyNames @("InternalName", "Id") -parentPropertyName "Fields" -executeQuery
    $web.Fields | select InternalName, Id
.EXAMPLE
   Load-CSOMProperties -object $web -propertyNames @("Title", "Url", "AllProperties") -executeQuery
   $web | select Title, Url, AllProperties
#>
function Load-CSOMProperties {
    [CmdletBinding(DefaultParameterSetName='ClientObject')]
    param (
        # The Microsoft.SharePoint.Client.ClientObject to populate.
        [Parameter(Mandatory = $true, ValueFromPipeline = $true, Position = 0, ParameterSetName = "ClientObject")]
        [Microsoft.SharePoint.Client.ClientObject]
        $object,

        # The Microsoft.SharePoint.Client.ClientObject that contains the collection object.
        [Parameter(Mandatory = $true, ValueFromPipeline = $true, Position = 0, ParameterSetName = "ClientObjectCollection")]
        [Microsoft.SharePoint.Client.ClientObject]
        $parentObject,

        # The Microsoft.SharePoint.Client.ClientObjectCollection to populate.
        [Parameter(Mandatory = $true, ValueFromPipeline = $true, Position = 1, ParameterSetName = "ClientObjectCollection")]
        [Microsoft.SharePoint.Client.ClientObjectCollection]
        $collectionObject,

        # The object properties to populate
        [Parameter(Mandatory = $true, Position = 1, ParameterSetName = "ClientObject")]
        [Parameter(Mandatory = $true, Position = 2, ParameterSetName = "ClientObjectCollection")]
        [string[]]
        $propertyNames,

        # The parent object's property name corresponding to the collection object to retrieve (this is required to build the correct lamda expression).
        [Parameter(Mandatory = $true, Position = 3, ParameterSetName = "ClientObjectCollection")]
        [string]
        $parentPropertyName,

        # If specified, execute the ClientContext.ExecuteQuery() method.
        [Parameter(Mandatory = $false, Position = 4)]
        [switch]
        $executeQuery
    )

    begin { }
    process {
        if ($PsCmdlet.ParameterSetName -eq "ClientObject") {
            $type = $object.GetType()
        } else {
            $type = $collectionObject.GetType() 
            if ($collectionObject -is [Microsoft.SharePoint.Client.ClientObjectCollection]) {
                $type = $collectionObject.GetType().BaseType.GenericTypeArguments[0]
            }
        }

        $exprType = [System.Linq.Expressions.Expression]
        $parameterExprType = [System.Linq.Expressions.ParameterExpression].MakeArrayType()
        $lambdaMethod = $exprType.GetMethods() | ? { $_.Name -eq "Lambda" -and $_.IsGenericMethod -and $_.GetParameters().Length -eq 2 -and $_.GetParameters()[1].ParameterType -eq $parameterExprType }
        $lambdaMethodGeneric = Invoke-Expression "`$lambdaMethod.MakeGenericMethod([System.Func``2[$($type.FullName),System.Object]])"
        $expressions = @()

        foreach ($propertyName in $propertyNames) {
            $param1 = [System.Linq.Expressions.Expression]::Parameter($type, "p")
            try {
                $name1 = [System.Linq.Expressions.Expression]::Property($param1, $propertyName)
            } catch {
                Write-Error "Instance property '$propertyName' is not defined for type $type"
                return
            }
            $body1 = [System.Linq.Expressions.Expression]::Convert($name1, [System.Object])
            $expression1 = $lambdaMethodGeneric.Invoke($null, [System.Object[]] @($body1, [System.Linq.Expressions.ParameterExpression[]] @($param1)))
 
            if ($collectionObject -ne $null) {
                $expression1 = [System.Linq.Expressions.Expression]::Quote($expression1)
            }
            $expressions += @($expression1)
        }


        if ($PsCmdlet.ParameterSetName -eq "ClientObject") {
            $object.Context.Load($object, $expressions)
            if ($executeQuery) { $object.Context.ExecuteQuery() }
        } else {
            $newArrayInitParam1 = Invoke-Expression "[System.Linq.Expressions.Expression``1[System.Func````2[$($type.FullName),System.Object]]]"
            $newArrayInit = [System.Linq.Expressions.Expression]::NewArrayInit($newArrayInitParam1, $expressions)

            $collectionParam = [System.Linq.Expressions.Expression]::Parameter($parentObject.GetType(), "cp")
            $collectionProperty = [System.Linq.Expressions.Expression]::Property($collectionParam, $parentPropertyName)

            $expressionArray = @($collectionProperty, $newArrayInit)
            $includeMethod = [Microsoft.SharePoint.Client.ClientObjectQueryableExtension].GetMethod("Include")
            $includeMethodGeneric = Invoke-Expression "`$includeMethod.MakeGenericMethod([$($type.FullName)])"

            $lambdaMethodGeneric2 = Invoke-Expression "`$lambdaMethod.MakeGenericMethod([System.Func``2[$($parentObject.GetType().FullName),System.Object]])"
            $callMethod = [System.Linq.Expressions.Expression]::Call($null, $includeMethodGeneric, $expressionArray)
            
            $expression2 = $lambdaMethodGeneric2.Invoke($null, @($callMethod, [System.Linq.Expressions.ParameterExpression[]] @($collectionParam)))

            $parentObject.Context.Load($parentObject, $expression2)
            if ($executeQuery) { $parentObject.Context.ExecuteQuery() }
        }
    }
    end { }
}
export-modulemember -function Load-CSOMProperties