PsModelUI.psm1
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Add-Type -AssemblyName PresentationFramework, PresentationCore, WindowsBase -ErrorAction Stop # Use an object so we can hot swap the runspacepool on calls to Set-ViewModelPool on all ViewModels if needed. $script:ViewModelThread = [System.Collections.Concurrent.ConcurrentDictionary[string, System.Management.Automation.Runspaces.RunspacePool]]::new() # [NoRunspaceAffinity()] class ViewModelBase : PSCustomObject, System.ComponentModel.INotifyPropertyChanged { # INotifyPropertyChanged Implementation [ComponentModel.PropertyChangedEventHandler]$PropertyChanged add_PropertyChanged([System.ComponentModel.PropertyChangedEventHandler]$handler) { $this.psobject.PropertyChanged = [Delegate]::Combine($this.psobject.PropertyChanged, $handler) } remove_PropertyChanged([System.ComponentModel.PropertyChangedEventHandler]$handler) { $this.psobject.PropertyChanged = [Delegate]::Remove($this.psobject.PropertyChanged, $handler) } RaisePropertyChanged([string]$propname) { if ($this.psobject.PropertyChanged) { $evargs = [System.ComponentModel.PropertyChangedEventArgs]::new($propname) $this.psobject.PropertyChanged.Invoke($this, $evargs) } } # End INotifyPropertyChanged Implementation ViewModelBase() { $this.psobject.UpdateWithDispatcherDelegate = $this.psobject.CreateDelegate($this.psobject.UpdateWithDispatcher) $this.psobject.AddPropertyChangedToProperties() } ViewModelBase([bool]$AddDefault) { $this.psobject.UpdateWithDispatcherDelegate = $this.psobject.CreateDelegate($this.psobject.UpdateWithDispatcher) if ($AddDefault) { $this.psobject.AddPropertyChangedToProperties() } } [void]AddPropertyChangedToProperties() { $this.psobject.AddPropertyChangedToProperties($null) } [void]AddPropertyChangedToProperties([string[]]$Exclude) { $PropertiesToExclude = 'PropertyChanged', 'Dispatcher', 'ViewModelThread', 'LastAction', 'UpdateWithDispatcherDelegate' + $Exclude $this.psobject.psobject.Members.Where({ $_.MemberType -eq 'Property' -and $_.IsSettable -eq $true -and $_.IsGettable -eq $true -and $_.Name -notin $PropertiesToExclude } ).ForEach( { $ProperName = if ($_.Name.StartsWith('_')) { $_.Name.Remove(0, 1) } else { $_.Name } $Splat = @{ Name = $ProperName MemberType = 'ScriptProperty' Value = [scriptblock]::Create('return ,$this.psobject.{0}' -f $_.Name) SecondValue = [scriptblock]::Create(('param($value) $this.psobject.{0} = $value $this.psobject.RaisePropertyChanged("{1}")' -f $_.Name, $ProperName) ) } $this | Add-Member @Splat } ) } [Delegate]CreateDelegate([System.Management.Automation.PSMethod]$Method) { return $this.psobject.CreateDelegate($Method, $this) } [Delegate]CreateDelegate([System.Management.Automation.PSMethod]$Method, $Target) { $reflectionMethod = if ($Target.GetType().Name -eq 'PSCustomObject') { $Target.psobject.GetType().GetMethod($Method.Name) } else { $Target.GetType().GetMethod($Method.Name) } $parameterTypes = [System.Linq.Enumerable]::Select($reflectionMethod.GetParameters(), [func[object, object]] { $args[0].parametertype }) $concatMethodTypes = $parameterTypes + $reflectionMethod.ReturnType $delegateType = [System.Linq.Expressions.Expression]::GetDelegateType($concatMethodTypes) $delegate = [delegate]::CreateDelegate($delegateType, $Target, $reflectionMethod.Name) return $delegate } [void]UpdateView([pscustomobject]$UpdateValue) { if ($null -eq $UpdateValue) { return } $this.psobject.InvokeDispatcher($UpdateValue) } hidden [void]UpdateWithDispatcher($UpdateValue) { $UpdateValue.psobject.Properties | ForEach-Object { try { $this.$($_.Name) = $_.Value } catch { Write-Warning ('Tried to update class property that does not exist: {0}' -f $_.Name) } } } hidden [void]InvokeDispatcher($UpdateValue) { $this.psobject.Dispatcher.BeginInvoke(9, $this.psobject.UpdateWithDispatcherDelegate, $UpdateValue) } [System.Threading.Tasks.Task]StartAsync($MethodToRunAsync, [ViewModelBase]$Target, $CommandParameter) { return $this.psobject.StartAsync($MethodToRunAsync, [ViewModelBase]$Target, $CommandParameter, $null) } [System.Threading.Tasks.Task]StartAsync($MethodToRunAsync, [ViewModelBase]$Target, $CommandParameter, $ActionCommand) { $Powershell = [powershell]::Create() $Powershell.RunspacePool = $Target.psobject.ViewModelThread['Pool'] # Will use a default runspace if ViewModelThread is $null $Delegate = if ($null -eq $CommandParameter -and $null -ne $ActionCommand) { { param($NoContextMethod, $ActionCommand) try { $NoContextMethod.Invoke() $null = $ActionCommand.psobject.Dispatcher.InvokeAsync($ActionCommand.psobject.RemoveWorkerDelegate) # Pipeline output can be received in $LastAction.Result } catch { throw $_ } } } elseif ($null -eq $CommandParameter -and $null -eq $ActionCommand) { { param($NoContextMethod) try { $NoContextMethod.Invoke() } catch { throw $_ } } } elseif ($null -ne $CommandParameter -and $null -eq $ActionCommand) { { param($NoContextMethod, $CommandParameter) try { $NoContextMethod.Invoke($CommandParameter) } catch { throw $_ } } } else { { param($NoContextMethod, $ActionCommand, $CommandParameter) try { $NoContextMethod.Invoke($CommandParameter) $ActionCommand.psobject.Dispatcher.InvokeAsync($ActionCommand.psobject.RemoveWorkerDelegate) } catch { throw $_ } } } $NoContext = $Delegate.Ast.GetScriptBlock() $null = $Powershell.AddScript($NoContext) $null = $Powershell.AddParameter('NoContextMethod', $MethodToRunAsync) if ($null -ne $CommandParameter) { $null = $Powershell.AddParameter('CommandParameter', $CommandParameter) } if ($null -ne $ActionCommand) { $null = $Powershell.AddParameter('ActionCommand', $ActionCommand) } $Handle = $Powershell.BeginInvoke() $EndInvokeDelegate = $this.psobject.CreateDelegate($Powershell.EndInvoke, $Powershell) # Not needed with pwsh $Task = [System.Threading.Tasks.Task]::Factory.FromAsync($Handle, $EndInvokeDelegate) $this.psobject.LastAction = $Task return $Task } $Dispatcher #= [System.Windows.Threading.Dispatcher]::CurrentDispatcher # requires types to be loaded in ScriptsToProcess [System.Collections.Concurrent.ConcurrentDictionary[string, System.Management.Automation.Runspaces.RunspacePool]]$ViewModelThread [System.Threading.Tasks.Task]$LastAction $UpdateWithDispatcherDelegate } class ActionCommand : ViewModelBase, System.Windows.Input.ICommand { # ICommand Implementation [System.EventHandler]$InternalCanExecuteChanged add_CanExecuteChanged([EventHandler] $value) { $this.psobject.InternalCanExecuteChanged = [Delegate]::Combine($this.psobject.InternalCanExecuteChanged, $value) } remove_CanExecuteChanged([EventHandler] $value) { $this.psobject.InternalCanExecuteChanged = [Delegate]::Remove($this.psobject.InternalCanExecuteChanged, $value) } [bool]CanExecute([object]$CommandParameter) { if ($this.psobject.Throttle -gt 0) { return ($this.psobject.Workers -lt $this.psobject.Throttle) } if ($this.psobject.CanExecuteAction) { return $this.psobject.CanExecuteAction.Invoke() } return $true } [void]Execute([object]$CommandParameter) { if ($this.psobject.Throttle -gt 0) { $this.Workers++ } $Delegate = if ($this.psobject.Action) { $this.psobject.Action } else { $this.psobject.ActionObject } if ($this.psobject.IsAsync) { if ($this.psobject.Throttle -gt 0) { $null = $this.psobject.StartAsync($Delegate, $this.psobject.Target, $null, $this) } else { $null = $this.psobject.StartAsync($Delegate, $this.psobject.Target, $null) } } else { $Delegate.Invoke() if ($this.psobject.Throttle -gt 0) { $this.psobject.RemoveWorker() } } } # End ICommand Implementation ActionCommand([System.Management.Automation.PSMethod]$Action) : Base($false) { $this.psobject.Init($Action, $false, $null, 0) } ActionCommand([System.Management.Automation.PSMethod]$Action, [bool]$IsAsync, [ViewModelBase]$Target, [int]$Throttle) : Base($false) { $this.psobject.Init($Action, $IsAsync, $Target, $Throttle) } hidden Init([System.Management.Automation.PSMethod]$Action, [bool]$IsAsync, [ViewModelBase]$Target, [int]$Throttle) { $Delegate = $this.psobject.CreateDelegate($Action, $Target) $this.psobject.Action = $Delegate $this.psobject.IsAsync = $IsAsync $this.psobject.Target = $Target $this.psobject.Throttle = $Throttle $this.psobject.RaiseCanExecuteChangedDelegate = $this.psobject.CreateDelegate($this.psobject.RaiseCanExecuteChanged) $this.psobject.RemoveWorkerDelegate = $this.psobject.CreateDelegate($this.psobject.RemoveWorker) @('Workers').ForEach( { $Splat = @{ Name = $_ MemberType = 'ScriptProperty' Value = [scriptblock]::Create('return ,$this.psobject.{0}' -f $_) SecondValue = [scriptblock]::Create('param($value) $this.psobject.{0} = $value $this.psobject.RaisePropertyChanged("{0}") if ($this.psobject.Dispatcher) {{ $this.psobject.RaiseCanExecuteChanged() }} elseif ([System.Windows.Threading.Dispatcher]::CurrentDispatcher.CheckAccess()) {{ $this.psobject.RaiseCanExecuteChanged() $this.psobject.Dispatcher = [System.Windows.Threading.Dispatcher]::CurrentDispatcher }} else {{ [System.Windows.Threading.Dispatcher]::CurrentDispatcher.InvokeAsync($this.psobject.RaiseCanExecuteChangedDelegate) }}' -f $_ ) } $this | Add-Member @Splat } ) } [void]RaiseCanExecuteChanged() { $eCanExecuteChanged = $this.psobject.InternalCanExecuteChanged if ($eCanExecuteChanged) { $eCanExecuteChanged.Invoke($this, [System.EventArgs]::Empty) } } [void]RemoveWorker() { $this.Workers-- } [ViewModelBase]$Target [bool]$IsAsync = $false $Action $ActionObject $CanExecuteAction $Workers = 0 $Throttle = 1 $RaiseCanExecuteChangedDelegate $RemoveWorkerDelegate } $script:Powershell = $null function New-UnboundClassInstance ([type] $type, [object[]] $arguments = $null, [scriptblock]$definition) { if ($null -eq $script:Powershell) { $script:Powershell = [powershell]::Create() $script:Powershell.AddScript({ function New-UnboundClassInstance ([type] $type, [object[]] $arguments, [scriptblock]$definition) { if ($definition) { $definition.Invoke() } [activator]::CreateInstance($type, $arguments) } }.Ast.GetScriptBlock() ).Invoke() $script:Powershell.Commands.Clear() } try { if ($null -eq $arguments) { $arguments = @() } $result = $script:Powershell.AddCommand('New-UnboundClassInstance'). AddParameter('type', $type). AddParameter('arguments', $arguments). AddParameter('definition', $definition). Invoke() return $result } finally { $script:Powershell.Commands.Clear() } } function New-ActionCommand { <# .SYNOPSIS Creates an [ActionCommand] object with the provided method in $Target. .PARAMETER MethodName Name of the method in $Target. .PARAMETER IsAsync This signals the equivalent command to be invoked in another runspace if $true or on the console thread. .PARAMETER Target The class object of the method. .PARAMETER Throttle The max number of times the equivalent method command can be running at a given time. #> [CmdletBinding()] param ( [Parameter(Mandatory)] [string]$MethodName, [bool]$IsAsync = $true, [object]$Target, [int]$Throttle = 1 ) $Method = if ($Target.GetType().Name -eq 'PSCustomObject') { $Target.psobject.$MethodName } else { $Target.$MethodName } [ActionCommand]::new($Method, $IsAsync, $Target, $Throttle) } function New-Class { <# .SYNOPSIS Dynamically creates a class object that inherits ViewModeBase. Properties preceeed by `$this` used in Methods that aren't defined in PropertyDeclaration will automatically be defined as a property of the class. Method overloads are not supported. Allows for classes of the same type name with different properties and methods but allows for hot reloading of classes. .EXAMPLE $A = New-Class -ClassName 'ClassType' -PropertyDeclaration 'One' $B = New-Class -ClassName 'ClassType' -PropertyInit ([pscustomobject]@{ Name = 'NewProperty' Type = ([string]) Init = 'Hello World' }) $C = New-Class -ClassName 'ClassType' -Methods ([pscustomobject]@{ Name = 'ClassMethod' Body = {return 'Hello World'} }) .PARAMETER ClassName The name of the class 'MyClass' Creates: class MyClass : ViewModeBase { MyClass() {} } .PARAMETER Inherits The name of the class to inherit and interface names. Follows powershell interitance so only ONE class can be inherited and any dotnet interfaces can be added. 'Foo', 'System.IDisposable', System.ComponentModel.INotifyPropertyChanged class Foo { $Property = 1 } class Bar : Foo, System.IDisposable, System.ComponentModel.INotifyPropertyChanged { $NewProperty = 2 Dispose(){} $PropertyChanged add_PropertyChanged([System.ComponentModel.PropertyChangedEventHandler]$handler) {} remove_PropertyChanged([System.ComponentModel.PropertyChangedEventHandler]$handler) {} } .PARAMETER PropertyDeclaration Takes an array of strings. @('property1', 'PropertY2') Creates: class ViewModel : ViewModelBase { $property1 $PropertY2 } .PARAMETER Methods Will also create class properties for methods that call $this.propertyname that isn't in $PropertyDeclaration Requires a hashtable of name and it's Body as a scriptblock @( DoMethod = {return 'hello world'} OtherMethod = {$this.Property = 'foo'} # if '$Property' is not defined in PropertyDeclaration, it will be added automatically. ) Creates: class ViewModel : ViewModelBase { $Property [object]DoMethod() { return "hello world" } [void]OtherMethod() { $this.Property = 'foo' } } .PARAMETER Unbound Creates the class with no runspace affinity if $true. Otherwise class methods cannot be called when the UI is running. .PARAMETER AsString Returns the full class definition as a string instead of the object. #> [CmdletBinding(DefaultParameterSetName = 'AsObject')] param ( [Parameter(Mandatory)] [string]$ClassName, [string[]]$Inherits = 'pscustomobject', [Parameter(ParameterSetName = 'AsObject')] [string[]]$PropertyDeclaration, [Parameter(ParameterSetName = 'AsTypeWithDefinition')] [pscustomobject[]]$PropertyInit, [pscustomobject[]]$Methods, [bool]$Unbound = $true, [bool]$AutomaticProperties = $false, [switch]$AsString ) $StringBuilder = [System.Text.StringBuilder]::new() # start class line $null = $StringBuilder.Append("class $ClassName") if ($Inherits) { $null = $StringBuilder.Append(' : ') $null = $StringBuilder.Append(($Inherits -join ',')) } $null = $StringBuilder.AppendLine(' {') # class properties foreach ($Name in $PropertyDeclaration) { if ($Name -notmatch '^\w+$') { throw 'property name can only contain letters and numbers' } $null = $StringBuilder.AppendLine(('$_{0}' -f $Name)) } foreach ($ClassProperty in $PropertyInit) { if ($ClassProperty.Name -notmatch '^\w+$') { throw 'property name can only contain letters and numbers' } if ($ClassProperty.ExcludePrefix) { $null = $StringBuilder.AppendLine(('[{0}]${1}' -f $ClassProperty.Type, $ClassProperty.Name)) } else { $null = $StringBuilder.AppendLine(('[{0}]$_{1}' -f $ClassProperty.Type, $ClassProperty.Name)) } } # base constructor $null = $StringBuilder.AppendLine(('{0}(){{' -f $ClassName)) foreach ($ClassProperty in $PropertyInit) { if ($null -eq $ClassProperty.Init -or $ClassProperty.Init.Ast.EndBlock.Statements.Count -eq 0) { continue } if ($ClassProperty.ExcludePrefix) { $BackingFieldName = "psobject.$($ClassProperty.Name)" } else { $BackingFieldName = "psobject._$($ClassProperty.Name)" } $RawText = @" `$this.$BackingFieldName = [scriptblock]::Create( @' ,($($ClassProperty.Init.ToString())) '@ ).InvokeReturnAsIs() "@ $null = $StringBuilder.AppendLine($RawText) } $null = $StringBuilder.AppendLine(('}}' -f $ClassName)) # methods foreach ($PSMethod in $Methods) { if (($PSMethod.Body.Ast.EndBlock.Statements.Where({ $null -ne $_.Pipeline })).Count -eq 0) { $null = $StringBuilder.Append(('[void]{0}(' -f $PSMethod.Name)) } else { $null = $StringBuilder.Append(('[object]{0}(' -f $PSMethod.Name)) } $ParameterText = if ($PSMethod.Body.Ast.ParamBlock.Parameters.Extent.Text) { $PSMethod.Body.Ast.ParamBlock.Parameters.Extent.Text -join ', ' } else { '' } $null = $StringBuilder.AppendLine(('{0}) {{' -f $ParameterText)) foreach ($Statement in $PSMethod.Body.Ast.EndBlock.Statements.Extent.Text) { $null = $StringBuilder.AppendLine($Statement) } $null = $StringBuilder.AppendLine('}') } # end class definition $null = $StringBuilder.AppendLine('}') # find all $this references from preliminary definition and create class properties for them. $UniqueProperties = [System.Collections.Generic.HashSet[string]]::new() if ($AutomaticProperties) { $PreliminaryDefinition = ([scriptblock]::Create($StringBuilder.ToString())) $ClassProperties = $PreliminaryDefinition.Ast.FindAll({ $args[0] -is [System.Management.Automation.Language.VariableExpressionAst] }, $true) | Where-Object { $_.VariablePath.UserPath -eq 'this' } # remove the newline and closing brace to add $this variables as properties from methods. $null = $StringBuilder.Remove($StringBuilder.Length - 3, 3) # get all unique $this properties and add them as $property if not added in $PropertyDeclaration foreach ($ClassProperty in $ClassProperties.Parent.Member.Extent.Text) { if ([string]::IsNullOrWhiteSpace($ClassProperty)) { continue } if ($PropertyDeclaration -contains $ClassProperty) { continue } if ($PropertyInit.Name -contains $ClassProperty) { continue } $null = $UniqueProperties.Add($ClassProperty) } foreach ($ClassProperty in $UniqueProperties.GetEnumerator()) { $null = $StringBuilder.AppendLine('$_{0}' -f $ClassProperty) } # end class definition $null = $StringBuilder.AppendLine('}') } if ($AsString) { return $StringBuilder.ToString() } $Definition = ([scriptblock]::Create($StringBuilder.ToString())) . $Definition $DynamicClass = if ($Unbound) { New-UnboundClassInstance $ClassName } else { [activator]::CreateInstance($ClassName) } foreach ($ClassProperty in $PropertyDeclaration) { $ProperName = if ($ClassProperty.StartsWith('_')) { $ClassProperty.Remove(0, 1) } else { $ClassProperty } $Splat = @{ Name = $ProperName MemberType = 'ScriptProperty' Value = [scriptblock]::Create('return ,$this.psobject.{0}' -f $ClassProperty) SecondValue = [scriptblock]::Create(('param($value) $this.psobject.{0} = $value $this.psobject.RaisePropertyChanged("{1}")' -f $ClassProperty, $ProperName) ) } $DynamicClass | Add-Member @Splat } foreach ($ClassProperty in $PropertyInit) { if ($ClassProperty.Get -and $ClassProperty.Set) { $DynamicClass | Add-Member -MemberType ScriptProperty -Name $ClassProperty.Name -Value $ClassProperty.Get.Ast.GetScriptBlock() -SecondValue $ClassProperty.Set.Ast.GetScriptBlock() -Force } else { if ($ClassProperty.ExcludePrefix) { $BackingFieldName = $ClassProperty.Name } else { $BackingFieldName = "_$($ClassProperty.Name)" } $Splat = @{ Name = $ClassProperty.Name MemberType = 'ScriptProperty' Value = [scriptblock]::Create('return ,$this.psobject.{0}' -f $BackingFieldName) SecondValue = [scriptblock]::Create(('param($value) $this.psobject.{0} = $value' -f $BackingFieldName) ) } $DynamicClass | Add-Member @Splat } } foreach ($ClassProperty in $UniqueProperties.GetEnumerator()) { $ProperName = "_$ClassProperty" $Splat = @{ Name = $ClassProperty MemberType = 'ScriptProperty' Value = [scriptblock]::Create('return ,$this.psobject.{0}' -f $ProperName) SecondValue = [scriptblock]::Create(('param($value) $this.psobject.{0} = $value' -f $ProperName) ) } $DynamicClass | Add-Member @Splat } $DynamicClass } function New-ClassMethod { <# .SYNOPSIS Creates a pscustomobject to be consumed by New-Class to create a class method. .PARAMETER Name Name of the method to be defined in the class by New-Class. .PARAMETER Body Body of the method to be defined in the class by New-Class. Uses the paramblock to define parameters that the method will receive. **Paramblock is not required if the method doesn't need parameters. All $this references will be of the class. #> [CmdletBinding()] param ( [Parameter(Mandatory)] [string]$Name, [Parameter(Mandatory)] [scriptblock]$Body # [bool]$IsAsync = $true ) [pscustomobject]@{ Name = $Name Body = $Body.Ast.GetScriptBlock() # IsAsync = $IsAsync } } function New-ClassProperty { <# .SYNOPSIS Creates a pscustomobject to be consumed by New-ViewModel to create a class property with initial value. .PARAMETER PropertyName Name of the property .PARAMETER Type Type of the property 'string' ([string]) 'object' 'int' ([System.Collections.Generic.List[object]]) .PARAMETER Init A scriptblock containing the initial value or object to create. Similar to list initialization in C++. Same braces! { 123 } { [System.Collections.Generic.List[object]]::new() } .PARAMETER ExcludePrefix Excludes adding an underscore "_" to the backing class property. The ScriptProperty will still be created and can be used for bindings, but it won't have a backing field with the same name. .PARAMETER Get A scriptblock that overwrites the default Get of the property. The scriptblock must return the value to be retrieved. .PARAMETER Set A scriptblock that overwrites the default the Set of the property. The scriptblock must have a parameter named 'value' to receive the value being set. If used with New-ViewModel, you will need to include $this.psobject.RaisePropertyChanged("PropertyName/_PropertyName") in the scriptblock to update bindings. .EXAMPLE New-ViewModelProperty -PropertyName 'a' -Type int -Init {1+1} The above will be consumed in New-ViewModel to generate: class Sample { [int]$_a Sample() { $this.a = [scriptblock]::Create( @' ,(1+1) '@ ).InvokeReturnAsIs() } } #> [CmdletBinding()] param ( [Parameter(Mandatory)] [string]$Name, [type]$Type, [scriptblock]$Init, [Parameter(ParameterSetName = 'WithAccessors')] [scriptblock]$Get, [Parameter(ParameterSetName = 'WithAccessors')] [scriptblock]$Set, [switch]$ExcludePrefix ) if ($Name -notmatch '^\w+$') { throw 'Name can only contain letters and numbers' } [pscustomobject]@{ Name = $Name Type = if ($Type) { $Type } else { [object] } Init = if ($Init.Ast.EndBlock.Statements.Count -gt 0) { $Init } else { $null } ExcludePrefix = $ExcludePrefix Get = if ($Get.Ast.EndBlock.Statements.Count -gt 0) { $Get } else { $null } Set = if ($Set.Ast.EndBlock.Statements.Count -gt 0) { $Set } else { $null } } } function New-ViewModel { <# .SYNOPSIS Dynamically creates a class object that inherits ViewModeBase. Properties preceeed by `$this` used in Methods that aren't defined in PropertyDeclaration will automatically be defined as a property of the class. Method overloads are not supported. Allows for classes of the same type name with different properties and methods but allows for hot reloading of classes. .EXAMPLE $A = New-ViewModel -ClassName 'ClassType' -PropertyDeclaration 'One' $B = New-ViewModel -ClassName 'ClassType' -PropertyInit ([pscustomobject]@{ Name = 'NewProperty' Type = ([string]) Init = 'Hello World' }) $C = New-ViewModel -ClassName 'ClassType' -Methods ([pscustomobject]@{ Name = 'ClassMethod' Body = {return 'Hello World'} Throttle = 1 IsAsync = $false }) .PARAMETER ClassName The name of the class 'MyClass' Creates: class MyClass : ViewModeBase { MyClass() {} } .PARAMETER PropertyDeclaration Takes an array of strings. @('property1', 'PropertY2') Creates: class ViewModel : ViewModelBase { $_property1 $_PropertY2 } .PARAMETER PropertyInit Use New-ClassProperty as a helper function to create the objects needed for this parameter. Takes an array of PSCustomObjects with the following properties: Name: Name of the property Type: Type of the property (e.g. [string], [int], etc.) Init: a scriptblock that defines the initial value of the property. It can reference other properties defined in $PropertyInit or $PropertyDeclaration with `$this.PropertyName`. It will be invoked in the constructor of the class so it can also reference other properties defined in the same $PropertyInit array. ExcludePrefix: if $true, the backing property will be created without the '_' prefix. This is useful for properties that need to be a the same backing name for binding purposes. Get: A scriptblock that defines the get accessor of the property. It can reference other properties defined in $PropertyInit or $PropertyDeclaration with `$this.PropertyName`. Set: A scriptblock that defines the set accessor of the property. It can reference other properties defined in $PropertyInit or $PropertyDeclaration with `$this.PropertyName`. .EXAMPLE New-ViewModel -ClassName 'Test' -PropertyInit @( [pscustomobject]@{Name = 'Property1'; Type = ([string]); Init = {'Hello World'}} [pscustomobject]@{Name = 'Property2'; Type = ([int]); Init = {42}; ExcludePrefix = $true} ) .PARAMETER Methods Use New-ViewModelMethod as a helper function to create the objects needed for this parameter. Takes an array of PSCustomObjects with the following properties: Name: name of the method Body: a scriptblock that defines the body of the method. It can reference properties defined in $PropertyInit or $PropertyDeclaration with `$this.PropertyName`. The paramblock defines the parameters that the method will receive. Can be strongly typed by defining the parameters in the paramblock with their types. CommandName: if ExcludeCommand is $true, this will be the name of the command property created for this method. If not provided, the command property will be named '{MethodName}Command'. ExcludeCommand: if $true, no command property will be created for this method. Throttle: the max number of times the equivalent method command can be running at a given time. Default is 1. IsAsync: this signals the equivalent command to be invoked in another runspace if $true or on the console thread. Default is $true. Will also create class properties for methods that call $this.propertyname that isn't in $PropertyDeclaration or $PropertyInit if $AutomaticProperties is $true. .EXAMPLE $Test = New-ViewModel -ClassName 'Test' -Methods @( [pscustomobject]@{ Name = 'DoMethod' Body = {return 'hello world'} Throttle = 1 IsAsync = $false } ) $Test.DoMethod() hello world Creates the following class: class ViewModel : ViewModelBase { $DoMethodCommand [object]DoMethod() { return "hello world" } } .PARAMETER Unbound Creates the class with no runspace affinity if $true. Otherwise class methods cannot be called when the UI is running if invoking async buttons. .PARAMETER AutomaticProperties Automatically creates class properties for any $this.property reference in the method bodies that isn't already defined in $PropertyDeclaration or $PropertyInit. This is useful for quickly prototyping but it is recommended to define properties explicitly for maintainability. .PARAMETER AsString Returns the full class definition as a string instead of the object. #> [CmdletBinding(DefaultParameterSetName = 'AsObject')] param ( [Parameter(Mandatory)] [string]$ClassName, [Parameter(ParameterSetName = 'AsObject')] [string[]]$PropertyDeclaration, [Parameter(ParameterSetName = 'AsTypeWithDefinition')] [pscustomobject[]]$PropertyInit, [pscustomobject[]]$Methods, [bool]$Unbound = $true, [bool]$AutomaticProperties = $false, [switch]$AsString ) $StringBuilder = [System.Text.StringBuilder]::new() # start class line $null = $StringBuilder.Append("class $ClassName") $null = $StringBuilder.Append(' : ViewModelBase') $null = $StringBuilder.AppendLine(' {') # class properties foreach ($Name in $PropertyDeclaration) { if ($Name -notmatch '^\w+$') { throw 'property name can only contain letters and numbers' } $null = $StringBuilder.AppendLine(('$_{0}' -f $Name)) } foreach ($ClassProperty in $PropertyInit) { if ($ClassProperty.Name -notmatch '^\w+$') { throw 'property name can only contain letters and numbers' } if ($ClassProperty.ExcludePrefix) { $null = $StringBuilder.AppendLine(('[{0}]${1}' -f $ClassProperty.Type, $ClassProperty.Name)) } else { $null = $StringBuilder.AppendLine(('[{0}]$_{1}' -f $ClassProperty.Type, $ClassProperty.Name)) } } # base constructor $null = $StringBuilder.AppendLine(('{0}(){{' -f $ClassName)) foreach ($ClassProperty in $PropertyInit) { if ($null -eq $ClassProperty.Init -or $ClassProperty.Init.Ast.EndBlock.Statements.Count -eq 0) { continue } if ($ClassProperty.ExcludePrefix) { $BackingFieldName = "psobject.$($ClassProperty.Name)" } else { $BackingFieldName = "psobject._$($ClassProperty.Name)" } $RawText = @" `$this.$BackingFieldName = [scriptblock]::Create( @' ,($($ClassProperty.Init.ToString())) '@ ).InvokeReturnAsIs() "@ $null = $StringBuilder.AppendLine($RawText) } $null = $StringBuilder.AppendLine(('}}' -f $ClassName)) # methods foreach ($PSMethod in $Methods) { # Create a command property for the method and append 'Command' to the end. if (-not $PSMethod.ExcludeCommand) { if ([string]::IsNullOrWhiteSpace($PSMethod.CommandName)) { $null = $StringBuilder.AppendLine(('${0}Command' -f $PSMethod.Name)) } else { $null = $StringBuilder.AppendLine(('${0}' -f $PSMethod.CommandName)) } } if (($PSMethod.Body.Ast.EndBlock.Statements.Where({ $null -ne $_.Pipeline })).Count -eq 0) { $null = $StringBuilder.Append(('[void]{0}(' -f $PSMethod.Name)) } else { $null = $StringBuilder.Append(('[object]{0}(' -f $PSMethod.Name)) } $ParameterText = if ($PSMethod.Body.Ast.ParamBlock.Parameters.Extent.Text) { $PSMethod.Body.Ast.ParamBlock.Parameters.Extent.Text -join ', ' } else { '' } $null = $StringBuilder.AppendLine(('{0}) {{' -f $ParameterText)) foreach ($Statement in $PSMethod.Body.Ast.EndBlock.Statements.Extent.Text) { $null = $StringBuilder.AppendLine($Statement) } $null = $StringBuilder.AppendLine('}') } # end class definition $null = $StringBuilder.AppendLine('}') # find all $this references from preliminary definition and create class properties for them. $UniqueProperties = [System.Collections.Generic.HashSet[string]]::new() if ($AutomaticProperties) { $PreliminaryDefinition = ([scriptblock]::Create($StringBuilder.ToString())) $ClassProperties = $PreliminaryDefinition.Ast.FindAll({ $args[0] -is [System.Management.Automation.Language.VariableExpressionAst] }, $true) | Where-Object { $_.VariablePath.UserPath -eq 'this' } # remove the newline and closing brace to add $this variables as properties from methods. $null = $StringBuilder.Remove($StringBuilder.Length - 3, 3) # get all unique $this properties and add them as $property if not added in $PropertyDeclaration foreach ($ClassProperty in $ClassProperties.Parent.Member.Extent.Text) { if ([string]::IsNullOrWhiteSpace($ClassProperty)) { continue } if ($PropertyDeclaration -contains $ClassProperty) { continue } if ($PropertyInit.Name -contains $ClassProperty) { continue } $null = $UniqueProperties.Add($ClassProperty) } foreach ($ClassProperty in $UniqueProperties.GetEnumerator()) { $null = $StringBuilder.AppendLine('$_{0}' -f $ClassProperty) } # end class definition $null = $StringBuilder.AppendLine('}') } if ($AsString) { return $StringBuilder.ToString() } $Definition = ([scriptblock]::Create($StringBuilder.ToString())) . $Definition $DynamicClass = if ($Unbound) { New-UnboundClassInstance $ClassName } else { [activator]::CreateInstance($ClassName) } # add a command property for each method foreach ($PSMethod in $Methods) { if ($PSMethod.ExcludeCommand) { continue } $CommandName = if ([string]::IsNullOrWhiteSpace($PSMethod.CommandName)) { "$($PSMethod.Name)Command" } else { $PSMethod.CommandName } $DynamicClass."$CommandName" = New-ActionCommand -MethodName $PSMethod.Name -Target $DynamicClass -Throttle $PSMethod.Throttle -IsAsync $PSMethod.IsAsync } if (!$script:ViewModelThread['Pool'] -or $script:ViewModelThread['Pool'].IsDisposed) { Set-ViewModelPool } $DynamicClass.psobject.ViewModelThread = $script:ViewModelThread # ViewModelBase automatically adds script properties so this differs from New-Class foreach ($ClassProperty in $PropertyInit) { if ($ClassProperty.Get -and $ClassProperty.Set) { $DynamicClass | Add-Member -MemberType ScriptProperty -Name $ClassProperty.Name -Value $ClassProperty.Get.Ast.GetScriptBlock() -SecondValue $ClassProperty.Set.Ast.GetScriptBlock() -Force } } $DynamicClass } function New-ViewModelMethod { <# .SYNOPSIS Creates a pscustomobject to be consumed by New-ViewModel to create a class method. .PARAMETER Name Name of the method to be defined in the class by New-ViewModel. .PARAMETER Body Body of the method to be defined in the class by New-ViewModel. Uses the paramblock to define parameters that the method will receive. **Paramblock is not required if the method doesn't need parameters. All $this references will be of the class. .PARAMETER CommandName If specified, a command with this name will be created as that invokes the method. .PARAMETER ExcludeCommand If $true, no command will be created for this method. CommandName will be ignored if ExcludeCommand is $true. .PARAMETER Throttle The max number of times the equivalent method command can be running at a given time. .PARAMETER IsAsync This signals the equivalent command to be invoked in another runspace if $true or on the console thread. #> [CmdletBinding()] param ( [Parameter(Mandatory)] [string]$Name, [Parameter(Mandatory)] [scriptblock]$Body, [string]$CommandName, [switch]$ExcludeCommand, [int]$Throttle = 1, [bool]$IsAsync = $true ) [pscustomobject]@{ Name = $Name Body = $Body.Ast.GetScriptBlock() CommandName = $CommandName ExcludeCommand = $ExcludeCommand Throttle = $Throttle IsAsync = $IsAsync } } function New-WpfObject { <# .SYNOPSIS Creates a WPF object with given Xaml from a string or file Uses the dedicated wpf xaml reader rather than the xmlreader. .PARAMETER Xaml The xaml string for to be parsed. .PARAMETER Path The full name to the xaml file to be parsed. .PARAMETER DataContext The ViewModel class object that the WpfObject will use. .EXAMPLE $Window = New-WpfObject -Xaml $Xaml -DataContext $ViewModel $ResourceDictionary = New-WpfObject -Path $Path #> [CmdletBinding(DefaultParameterSetName = 'Path')] param ( [Parameter(Mandatory, ValueFromPipeline, Position = 0, ParameterSetName = 'HereString')] [string[]]$Xaml, [Parameter(Mandatory, ValueFromPipeline, ValueFromPipelineByPropertyName, Position = 0, ParameterSetName = 'Path')] [ValidateScript({ Test-Path $_ })] [string[]]$Path, [string]$BaseUri, [ViewModelBase]$DataContext ) process { $Xml = [xml]::new() $RawXaml = if ($PSBoundParameters.ContainsKey('Path')) { $Xml.Load($Path) $Xml.InnerXml } else { $Xml.LoadXml($Xaml) $Xml.InnerXml } $WpfObject = [System.Windows.Markup.XamlReader]::Parse($RawXaml) if ($DataContext) { # because $DataContext can be created unbound, it may not have the same dispatcher as $WpfObject so it is set here. $DataContext.psobject.Dispatcher = $WpfObject.Dispatcher $WpfObject.DataContext = $DataContext } $WpfObject } } function Set-ViewModelPool { <# .SYNOPSIS Creates and opens the global runspacepool to be used by each viewmodel created by New-ViewModel. .DESCRIPTION Runspacepool is stored in module script scope: $script:ViewModelThread as a concurrent dictionary. It is added to each ViewModel created by New-ViewModel. Will be disposed and recreated on each call. .PARAMETER MaxRunspaces Max number of runspaces in the pool to be available for use. .PARAMETER Functions Name of the function defined inline to be available in the runspacepool. .PARAMETER StartupScripts Full paths of the scripts to run in the new runspace created by the runspacepool. #> [CmdletBinding()] param ( [int]$MaxRunspaces = $([int]$env:NUMBER_OF_PROCESSORS + 1), [string[]]$Functions, [string[]]$StartupScripts ) $State = [System.Management.Automation.Runspaces.InitialSessionState]::CreateDefault() $State.ThrowOnRunspaceOpenError = $true foreach ($Name in $Functions) { $FunctionDefinition = Get-Content "Function:\$Name" -ErrorAction Stop $State.Commands.Add([System.Management.Automation.Runspaces.SessionStateFunctionEntry]::new($Name, $FunctionDefinition)) } foreach ($ScriptPath in $StartupScripts) { $null = $State.StartupScripts.Add($ScriptPath) } if ($script:ViewModelThread['Pool']) { $script:ViewModelThread['Pool'].Dispose() } $script:ViewModelThread['Pool'] = [RunspaceFactory]::CreateRunspacePool(1, $MaxRunspaces, $State, (Get-Host)) $script:ViewModelThread['Pool'].CleanupInterval = [timespan]::FromMinutes(5) $script:ViewModelThread['Pool'].Open() } |