所以我真正想要的是在PS模块中有些可用的标签完成。 ValidateSet似乎是去这里的方式。
不幸的是我的数据是动态的，因此我无法预先使用所有有效值来注释参数。 DynamicParameters / IDynamicParameters似乎是 问题的解决方案。
把这些东西放在一起（并将我的失败减少到简单的测试用例）我们最终得到：
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Management.Automation;
using System.Text;
using System.Threading.Tasks;
namespace PSDummy
{
[Cmdlet(VerbsCommon.Get, "BookDetails")]
public class GetBookDetails : Cmdlet, IDynamicParameters
{
IDictionary<string, string[]> m_dummyData = new Dictionary<string, string[]> {
{"Terry Pratchett", new [] {"Small Gods", "Mort", "Eric"}},
{"Douglas Adams", new [] {"Hitchhiker's Guide", "The Meaning of Liff"}}
};
private RuntimeDefinedParameter m_authorParameter;
private RuntimeDefinedParameter m_bookParameter;
protected override void ProcessRecord()
{
// Do stuff here..
}
public object GetDynamicParameters()
{
var parameters = new RuntimeDefinedParameterDictionary();
m_authorParameter = CreateAuthorParameter();
m_bookParameter = CreateBookParameter();
parameters.Add(m_authorParameter.Name, m_authorParameter);
parameters.Add(m_bookParameter.Name, m_bookParameter);
return parameters;
}
private RuntimeDefinedParameter CreateAuthorParameter()
{
var p = new RuntimeDefinedParameter(
"Author",
typeof(string),
new Collection<Attribute>
{
new ParameterAttribute {
ParameterSetName = "BookStuff",
Position = 0,
Mandatory = true
},
new ValidateSetAttribute(m_dummyData.Keys.ToArray()),
new ValidateNotNullOrEmptyAttribute()
});
// Actually this is always mandatory, but sometimes I can fall back to a default
// value. How? p.Value = mydefault?
return p;
}
private RuntimeDefinedParameter CreateBookParameter()
{
// How to define a ValidateSet based on the parameter value for
// author?
var p = new RuntimeDefinedParameter(
"Book",
typeof(string),
new Collection<Attribute>
{
new ParameterAttribute {
ParameterSetName = "BookStuff",
Position = 1,
Mandatory = true
},
new ValidateSetAttribute(new string[1] { string.Empty }/* cannot fill this, because I cannot access the author */),
new ValidateNotNullOrEmptyAttribute()
});
return p;
}
}
}
不幸的是，这个小小的片段已经引发了很多问题。有序下降：
我无法看到如何在参数之间建立连接。如果您选择作者，则应该只能选择与作者匹配的书籍。到目前为止GetDynamicParameters()似乎总是无状态：我看不到访问不同/早期动态参数的值的方法。尝试将其保留在一个字段中，尝试搜索MyInvocation - 没有运气。这甚至可能吗？
如何定义必需参数的默认值？不适合这个愚蠢的例子，但我们可以说你可以存储你最喜欢的作者。从现在开始，我想默认为该作者，但是仍然必须指向作者。你给了我一个默认值（并且仍然可以指定别的东西）或者你需要明确。
带空格的字符串的标签完成看起来很奇怪/破坏/有限 - 因为它没有用引号括起该值（例如，如果您键入dir C:\Program <tab>，cmd.exe就会这样做）。因此，标签完成实际上打破调用（如果上述问题将得到解决，Get-BookDetails Ter<tab>会/将扩展为Get-BookDetails Terry Pratchett，这将姓氏放在参数位置1又称＆＃ 39;书＆＃39;
难道不是那么难，肯定有人做过类似的事吗？
更新：经过另一个修补和愚弄的好日子后，我没有看到一种方法来完成这项工作。命令行开关是无状态的，将一遍又一遍地实例化。在我可以定义动态参数（GetDynamicParameters）的时间点，我无法访问它们的（当前）值/看到它们被绑定的内容 - 例如MyInvocation.BoundParameters为零。我将这个问题保持开放，但似乎并不支持这个问题。我看到的所有示例都根据静态值的值添加动态参数 - 这与此处不相关。开溜。
答案 0 :(得分：9)
我认为这很有效。不幸的是，它使用反射来获取第一个项目符号的某些cmdlet私有成员。我从Garrett Serack得到了这个想法。我不确定我是否完全理解如何做默认作者，所以我这样做是为了让最后一位有效的作者存储在一个静态字段中，这样你就不需要了 - 下一次使用。
以下是代码：
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Management.Automation;
using System.Text;
using System.Threading.Tasks;
namespace PSDummy
{
internal class DynParamQuotedString {
/*
This works around the PowerShell bug where ValidateSet values aren't quoted when necessary, and
adding the quotes breaks it. Example:
ValidateSet valid values = 'Test string' (The quotes are part of the string)
PowerShell parameter binding would interperet that as [Test string] (no single quotes), which wouldn't match
the valid value (which has the quotes). If you make the parameter a DynParamQuotedString, though,
the parameter binder will coerce [Test string] into an instance of DynParamQuotedString, and the binder will
call ToString() on the object, which will add the quotes back in.
*/
internal static string DefaultQuoteCharacter = "'";
public DynParamQuotedString(string quotedString) : this(quotedString, DefaultQuoteCharacter) {}
public DynParamQuotedString(string quotedString, string quoteCharacter) {
OriginalString = quotedString;
_quoteCharacter = quoteCharacter;
}
public string OriginalString { get; set; }
string _quoteCharacter;
public override string ToString() {
// I'm sure this is missing some other characters that need to be escaped. Feel free to add more:
if (System.Text.RegularExpressions.Regex.IsMatch(OriginalString, @"\s|\(|\)|""|'")) {
return string.Format("{1}{0}{1}", OriginalString.Replace(_quoteCharacter, string.Format("{0}{0}", _quoteCharacter)), _quoteCharacter);
}
else {
return OriginalString;
}
}
public static string[] GetQuotedStrings(IEnumerable<string> values) {
var returnList = new List<string>();
foreach (string currentValue in values) {
returnList.Add((new DynParamQuotedString(currentValue)).ToString());
}
return returnList.ToArray();
}
}
[Cmdlet(VerbsCommon.Get, "BookDetails")]
public class GetBookDetails : PSCmdlet, IDynamicParameters
{
IDictionary<string, string[]> m_dummyData = new Dictionary<string, string[]>(StringComparer.OrdinalIgnoreCase) {
{"Terry Pratchett", new [] {"Small Gods", "Mort", "Eric"}},
{"Douglas Adams", new [] {"Hitchhiker's Guide", "The Meaning of Liff"}},
{"An 'Author' (notice the ')", new [] {"A \"book\"", "Another 'book'","NoSpace(ButCharacterThatShouldBeEscaped)", "NoSpace'Quoted'", "NoSpace\"Quoted\""}} // Test value I added
};
protected override void ProcessRecord()
{
WriteObject(string.Format("Author = {0}", _author));
WriteObject(string.Format("Book = {0}", ((DynParamQuotedString) MyInvocation.BoundParameters["Book"]).OriginalString));
}
// Making this static means it should keep track of the last author used
static string _author;
public object GetDynamicParameters()
{
// Get 'Author' if found, otherwise get first unnamed value
string author = GetUnboundValue("Author", 0) as string;
if (!string.IsNullOrEmpty(author)) {
_author = author.Trim('\'').Replace(
string.Format("{0}{0}", DynParamQuotedString.DefaultQuoteCharacter),
DynParamQuotedString.DefaultQuoteCharacter
);
}
var parameters = new RuntimeDefinedParameterDictionary();
bool isAuthorParamMandatory = true;
if (!string.IsNullOrEmpty(_author) && m_dummyData.ContainsKey(_author)) {
isAuthorParamMandatory = false;
var m_bookParameter = new RuntimeDefinedParameter(
"Book",
typeof(DynParamQuotedString),
new Collection<Attribute>
{
new ParameterAttribute {
ParameterSetName = "BookStuff",
Position = 1,
Mandatory = true
},
new ValidateSetAttribute(DynParamQuotedString.GetQuotedStrings(m_dummyData[_author])),
new ValidateNotNullOrEmptyAttribute()
}
);
parameters.Add(m_bookParameter.Name, m_bookParameter);
}
// Create author parameter. Parameter isn't mandatory if _author
// has a valid author in it
var m_authorParameter = new RuntimeDefinedParameter(
"Author",
typeof(DynParamQuotedString),
new Collection<Attribute>
{
new ParameterAttribute {
ParameterSetName = "BookStuff",
Position = 0,
Mandatory = isAuthorParamMandatory
},
new ValidateSetAttribute(DynParamQuotedString.GetQuotedStrings(m_dummyData.Keys.ToArray())),
new ValidateNotNullOrEmptyAttribute()
}
);
parameters.Add(m_authorParameter.Name, m_authorParameter);
return parameters;
}
/*
TryGetProperty() and GetUnboundValue() are from here: https://gist.github.com/fearthecowboy/1936f841d3a81710ae87
Source created a dictionary for all unbound values; I had issues getting ValidateSet on Author parameter to work
if I used that directly for some reason, but changing it into a function to get a specific parameter seems to work
*/
object TryGetProperty(object instance, string fieldName) {
var bindingFlags = System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.Static | System.Reflection.BindingFlags.Public;
// any access of a null object returns null.
if (instance == null || string.IsNullOrEmpty(fieldName)) {
return null;
}
var propertyInfo = instance.GetType().GetProperty(fieldName, bindingFlags);
if (propertyInfo != null) {
try {
return propertyInfo.GetValue(instance, null);
}
catch {
}
}
// maybe it's a field
var fieldInfo = instance.GetType().GetField(fieldName, bindingFlags);
if (fieldInfo!= null) {
try {
return fieldInfo.GetValue(instance);
}
catch {
}
}
// no match, return null.
return null;
}
object GetUnboundValue(string paramName) {
return GetUnboundValue(paramName, -1);
}
object GetUnboundValue(string paramName, int unnamedPosition) {
// If paramName isn't found, value at unnamedPosition will be returned instead
var context = TryGetProperty(this, "Context");
var processor = TryGetProperty(context, "CurrentCommandProcessor");
var parameterBinder = TryGetProperty(processor, "CmdletParameterBinderController");
var args = TryGetProperty(parameterBinder, "UnboundArguments") as System.Collections.IEnumerable;
if (args != null) {
var currentParameterName = string.Empty;
object unnamedValue = null;
int i = 0;
foreach (var arg in args) {
var isParameterName = TryGetProperty(arg, "ParameterNameSpecified");
if (isParameterName != null && true.Equals(isParameterName)) {
string parameterName = TryGetProperty(arg, "ParameterName") as string;
currentParameterName = parameterName;
continue;
}
// Treat as a value:
var parameterValue = TryGetProperty(arg, "ArgumentValue");
if (currentParameterName != string.Empty) {
// Found currentParameterName's value. If it matches paramName, return
// it
if (currentParameterName.Equals(paramName, StringComparison.OrdinalIgnoreCase)) {
return parameterValue;
}
}
else if (i++ == unnamedPosition) {
unnamedValue = parameterValue; // Save this for later in case paramName isn't found
}
// Found a value, so currentParameterName needs to be cleared
currentParameterName = string.Empty;
}
if (unnamedValue != null) {
return unnamedValue;
}
}
return null;
}
}
}