上下文是我正在处理PowerShell流程的一组包装器（解释器，如果你愿意的话），以增加简单性 - 最重要的是 - 标准化由我的同事制作的报告。
我为此进行实验的片段如下：
Add-Type -Path ".\itextsharp.dll"
function CreateReport([string]$Path = ".\Report.pdf")
{
#Create Document, define basic properties
$Document = New-Object iTextSharp.text.Document
$Document.SetPageSize([iTextSharp.text.PageSize]::A4)
$Document.SetMargins(5,5,5,5)
$Document.AddAuthor($env:USERNAME)
#Define methods
Add-Member -in $Document scriptmethod AddParagraph {
param([string]$Text = "Empty paragraph")
$Paragraph = New-Object iTextSharp.text.Paragraph
$Paragraph.Add($Text)
$this.Add($Paragraph)
}
return $Document
}
（我很清楚参数$Path没有做任何事情，这是供以后使用）
根据我的理解，这应该有效，但事实并非如此。最糟糕的是，我无法弄明白为什么。我测试如下：
$TestDoc = CreateReport
$TestDoc.AddParagraph("asdf")
它引发了以下异常：
Method invocation failed because [System.Boolean] does not contain a method named 'AddParagraph'.
At line:1 char:1
+ $TestDoc.AddParagraph("asdf")
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: (:) [], RuntimeException
+ FullyQualifiedErrorId : MethodNotFound
为什么PowerShell认为我试图在布尔值中调用方法？它不识别/支持iTextSharp.text.Document对象类型吗？
如上所述，这里是来自CreateReport的成员列表，我的职能是：
PS C:\temp\Robin> CreateReport | Get-Member
TypeName: System.Boolean
Name MemberType Definition
---- ---------- ----------
CompareTo Method int CompareTo(System.Object obj), int CompareTo(bool value), int IComparable.CompareTo(System.Object obj), int IComparable[bool].CompareTo(bool...
Equals Method bool Equals(System.Object obj), bool Equals(bool obj), bool IEquatable[bool].Equals(bool other)
GetHashCode Method int GetHashCode()
GetType Method type GetType()
GetTypeCode Method System.TypeCode GetTypeCode(), System.TypeCode IConvertible.GetTypeCode()
ToBoolean Method bool IConvertible.ToBoolean(System.IFormatProvider provider)
ToByte Method byte IConvertible.ToByte(System.IFormatProvider provider)
ToChar Method char IConvertible.ToChar(System.IFormatProvider provider)
ToDateTime Method datetime IConvertible.ToDateTime(System.IFormatProvider provider)
ToDecimal Method decimal IConvertible.ToDecimal(System.IFormatProvider provider)
ToDouble Method double IConvertible.ToDouble(System.IFormatProvider provider)
ToInt16 Method int16 IConvertible.ToInt16(System.IFormatProvider provider)
ToInt32 Method int IConvertible.ToInt32(System.IFormatProvider provider)
ToInt64 Method long IConvertible.ToInt64(System.IFormatProvider provider)
ToSByte Method sbyte IConvertible.ToSByte(System.IFormatProvider provider)
ToSingle Method float IConvertible.ToSingle(System.IFormatProvider provider)
ToString Method string ToString(), string ToString(System.IFormatProvider provider), string IConvertible.ToString(System.IFormatProvider provider)
ToType Method System.Object IConvertible.ToType(type conversionType, System.IFormatProvider provider)
ToUInt16 Method uint16 IConvertible.ToUInt16(System.IFormatProvider provider)
ToUInt32 Method uint32 IConvertible.ToUInt32(System.IFormatProvider provider)
ToUInt64 Method uint64 IConvertible.ToUInt64(System.IFormatProvider provider)
TypeName: iTextSharp.text.Document
Name MemberType Definition
---- ---------- ----------
Add Method bool Add(iTextSharp.text.IElement element), bool IElementListener.Add(iTextSharp.text.IElement element)
AddAuthor Method bool AddAuthor(string author)
AddCreationDate Method bool AddCreationDate()
AddCreator Method bool AddCreator(string creator)
AddDocListener Method void AddDocListener(iTextSharp.text.IDocListener listener)
AddHeader Method bool AddHeader(string name, string content)
AddKeywords Method bool AddKeywords(string keywords)
AddLanguage Method bool AddLanguage(string language)
AddProducer Method bool AddProducer()
AddSubject Method bool AddSubject(string subject)
AddTitle Method bool AddTitle(string title)
Close Method void Close(), void IDocListener.Close()
CloseDocument Method void CloseDocument()
Dispose Method void Dispose(), void IDisposable.Dispose()
Equals Method bool Equals(System.Object obj)
GetAccessibleAttribute Method iTextSharp.text.pdf.PdfObject GetAccessibleAttribute(iTextSharp.text.pdf.PdfName key), iTextSharp.text.pdf.PdfObject IAccessi...
GetAccessibleAttributes Method System.Collections.Generic.Dictionary[iTextSharp.text.pdf.PdfName,iTextSharp.text.pdf.PdfObject] GetAccessibleAttributes(), S...
GetBottom Method float GetBottom(float margin)
GetHashCode Method int GetHashCode()
GetLeft Method float GetLeft(float margin)
GetRight Method float GetRight(float margin)
GetTop Method float GetTop(float margin)
GetType Method type GetType()
IsMarginMirroring Method bool IsMarginMirroring()
IsOpen Method bool IsOpen()
NewPage Method bool NewPage(), bool IDocListener.NewPage()
Open Method void Open(), void IDocListener.Open()
OpenDocument Method void OpenDocument()
RemoveIDocListener Method void RemoveIDocListener(iTextSharp.text.IDocListener listener)
ResetPageCount Method void ResetPageCount(), void IDocListener.ResetPageCount()
SetAccessibleAttribute Method void SetAccessibleAttribute(iTextSharp.text.pdf.PdfName key, iTextSharp.text.pdf.PdfObject value), void IAccessibleElement.Se...
SetMarginMirroring Method bool SetMarginMirroring(bool marginMirroring), bool IDocListener.SetMarginMirroring(bool marginMirroring)
SetMarginMirroringTopBottom Method bool SetMarginMirroringTopBottom(bool marginMirroringTopBottom), bool IDocListener.SetMarginMirroringTopBottom(bool marginMir...
SetMargins Method bool SetMargins(float marginLeft, float marginRight, float marginTop, float marginBottom), bool IDocListener.SetMargins(float...
SetPageSize Method bool SetPageSize(iTextSharp.text.Rectangle pageSize), bool IDocListener.SetPageSize(iTextSharp.text.Rectangle pageSize)
ToString Method string ToString()
Bottom Property float Bottom {get;}
BottomMargin Property float BottomMargin {get;}
HtmlStyleClass Property string HtmlStyleClass {get;set;}
ID Property iTextSharp.text.AccessibleElementId ID {get;set;}
IsInline Property bool IsInline {get;}
JavaScript_onLoad Property string JavaScript_onLoad {get;set;}
JavaScript_onUnLoad Property string JavaScript_onUnLoad {get;set;}
Left Property float Left {get;}
LeftMargin Property float LeftMargin {get;}
PageCount Property int PageCount {set;}
PageNumber Property int PageNumber {get;}
PageSize Property iTextSharp.text.Rectangle PageSize {get;}
Right Property float Right {get;}
RightMargin Property float RightMargin {get;}
Role Property iTextSharp.text.pdf.PdfName Role {get;set;}
Top Property float Top {get;}
TopMargin Property float TopMargin {get;}
AddParagraph ScriptMethod System.Object AddParagraph();
以下是$Document的成员：
TypeName: iTextSharp.text.Document
Name MemberType Definition
---- ---------- ----------
Add Method bool Add(iTextSharp.text.IElement element), bool IElementListener.Add(iTextSharp.text.IElement element)
AddAuthor Method bool AddAuthor(string author)
AddCreationDate Method bool AddCreationDate()
AddCreator Method bool AddCreator(string creator)
AddDocListener Method void AddDocListener(iTextSharp.text.IDocListener listener)
AddHeader Method bool AddHeader(string name, string content)
AddKeywords Method bool AddKeywords(string keywords)
AddLanguage Method bool AddLanguage(string language)
AddProducer Method bool AddProducer()
AddSubject Method bool AddSubject(string subject)
AddTitle Method bool AddTitle(string title)
Close Method void Close(), void IDocListener.Close()
CloseDocument Method void CloseDocument()
Dispose Method void Dispose(), void IDisposable.Dispose()
Equals Method bool Equals(System.Object obj)
GetAccessibleAttribute Method iTextSharp.text.pdf.PdfObject GetAccessibleAttribute(iTextSharp.text.pdf.PdfName key), iTextSharp.text.pdf.PdfObject IAccessibl...
GetAccessibleAttributes Method System.Collections.Generic.Dictionary[iTextSharp.text.pdf.PdfName,iTextSharp.text.pdf.PdfObject] GetAccessibleAttributes(), Sys...
GetBottom Method float GetBottom(float margin)
GetHashCode Method int GetHashCode()
GetLeft Method float GetLeft(float margin)
GetRight Method float GetRight(float margin)
GetTop Method float GetTop(float margin)
GetType Method type GetType()
IsMarginMirroring Method bool IsMarginMirroring()
IsOpen Method bool IsOpen()
NewPage Method bool NewPage(), bool IDocListener.NewPage()
Open Method void Open(), void IDocListener.Open()
OpenDocument Method void OpenDocument()
RemoveIDocListener Method void RemoveIDocListener(iTextSharp.text.IDocListener listener)
ResetPageCount Method void ResetPageCount(), void IDocListener.ResetPageCount()
SetAccessibleAttribute Method void SetAccessibleAttribute(iTextSharp.text.pdf.PdfName key, iTextSharp.text.pdf.PdfObject value), void IAccessibleElement.SetA...
SetMarginMirroring Method bool SetMarginMirroring(bool marginMirroring), bool IDocListener.SetMarginMirroring(bool marginMirroring)
SetMarginMirroringTopBottom Method bool SetMarginMirroringTopBottom(bool marginMirroringTopBottom), bool IDocListener.SetMarginMirroringTopBottom(bool marginMirro...
SetMargins Method bool SetMargins(float marginLeft, float marginRight, float marginTop, float marginBottom), bool IDocListener.SetMargins(float m...
SetPageSize Method bool SetPageSize(iTextSharp.text.Rectangle pageSize), bool IDocListener.SetPageSize(iTextSharp.text.Rectangle pageSize)
ToString Method string ToString()
Bottom Property float Bottom {get;}
BottomMargin Property float BottomMargin {get;}
HtmlStyleClass Property string HtmlStyleClass {get;set;}
ID Property iTextSharp.text.AccessibleElementId ID {get;set;}
IsInline Property bool IsInline {get;}
JavaScript_onLoad Property string JavaScript_onLoad {get;set;}
JavaScript_onUnLoad Property string JavaScript_onUnLoad {get;set;}
Left Property float Left {get;}
LeftMargin Property float LeftMargin {get;}
PageCount Property int PageCount {set;}
PageNumber Property int PageNumber {get;}
PageSize Property iTextSharp.text.Rectangle PageSize {get;}
Right Property float Right {get;}
RightMargin Property float RightMargin {get;}
Role Property iTextSharp.text.pdf.PdfName Role {get;set;}
Top Property float Top {get;}
TopMargin Property float TopMargin {get;}
答案 0 :(得分：1)
您的函数返回两个对象，首先是boolean和第二个iTextSharp.text.Document对象。 Add-Member除非设置了-PassThru参数，否则不会返回值，即使在这种情况下，该值也是对象，而不是boolean。
因此，您调用的iTextSharp.text.Document方法之一就是返回$true或$false。您可以将返回值重定向到$null以解决问题：
$Document.SetPageSize([iTextSharp.text.PageSize]::A4) | Out-Null
$Document.SetMargins(5,5,5,5) | Out-Null
$Document.AddAuthor($env:USERNAME) | Out-Null