dotnet · BillWagner · Nov 29, 2021 · Nov 24, 2021 · Nov 24, 2021 · Nov 25, 2021
@@ -0,0 +1,37 @@
+module ActivatorX
+
+//<snippet1>
+open System
+open System.Reflection
+open System.Text
+
+type SomeType() =
+    member _.DoSomething(x) = printfn $"100 / {x} = {100 / x}"
+
+//<snippet2>
+// Create an instance of the StringBuilder type using Activator.CreateInstance.
+let o = Activator.CreateInstance typeof<StringBuilder>
+
+// Append a string into the StringBuilder object and display the StringBuilder.
+let sb = o :?> StringBuilder
+sb.Append "Hello, there." |> ignore
+printfn $"{sb}"
+//</snippet2>
+
+//<snippet3>
+// Create an instance of the SomeType class that is defined in this assembly.
+let oh = 
+    Activator.CreateInstanceFrom(Assembly.GetEntryAssembly().Location, typeof<SomeType>.FullName)
+
+// Call an instance method defined by the SomeType type using this object.
+let st = oh.Unwrap() :?> SomeType
+
+st.DoSomething 5
+//</snippet3>
+
+(* This code produces the following output:
+
+Hello, there.
+100 / 5 = 20
+ *)
+//</snippet1>
@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="ActivatorX.fs" />
+    <Compile Include="source2.fs" />
+  </ItemGroup>
+
+</Project>
@@ -0,0 +1,54 @@
+module source2
+
+//<snippet4>
+open System
+
+let instanceSpec =
+    "System.EventArgs;System.Random;System.Exception;System.Object;System.Version"
+
+let instances = instanceSpec.Split ';'
+let instlist = Array.zeroCreate instances.Length
+let mutable item = obj ()
+
+for i = 0 to instances.Length - 1 do
+    // create the object from the specification string
+    printfn $"Creating instance of: {instances.[i]}"
+    item <- Activator.CreateInstance(Type.GetType instances.[i])
+    instlist.[i] <- item
+
+printfn "\nObjects and their default values:\n"
+
+for o in instlist do
+    printfn $"Type:     {o.GetType().FullName}\nValue:    {o}\nHashCode: {o.GetHashCode()}\n"
+
+
+// This program will display output similar to the following:
+//
+// Creating instance of: System.EventArgs
+// Creating instance of: System.Random
+// Creating instance of: System.Exception
+// Creating instance of: System.Object
+// Creating instance of: System.Version
+//
+// Objects and their default values:
+//
+// Type:     System.EventArgs
+// Value:    System.EventArgs
+// HashCode: 46104728
+//
+// Type:     System.Random
+// Value:    System.Random
+// HashCode: 12289376
+//
+// Type:     System.Exception
+// Value:    System.Exception: Exception of type 'System.Exception' was thrown.
+// HashCode: 55530882
+//
+// Type:     System.Object
+// Value:    System.Object
+// HashCode: 30015890
+//
+// Type:     System.Version
+// Value:    0.0
+// HashCode: 1048575
+//</snippet4>
@@ -0,0 +1,6 @@
+module remarks
+
+// <Snippet1>
+let factory<'T when 'T : (new: unit -> 'T)> =
+    new 'T()
+// </Snippet1>
@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="remarks.fs" />
+  </ItemGroup>
+
+</Project>
@@ -0,0 +1,14 @@
+module CreateInstance5
+// <Snippet5>
+open System
+
+// Initialize array of characters from a to z.
+let chars = [| 'a' .. 'z' |]
+
+let obj = Activator.CreateInstance(typeof<string>, chars[13..22])
+
+printfn $"{obj}"
+
+// The example displays the following output:
+//       nopqrstuvw
+// </Snippet5>
@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Library</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="..\personinfo.fs" />
+  </ItemGroup>
+
+</Project>
@@ -0,0 +1,20 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="createinstanceex1.fs" />
+    <Compile Include="createinstanceex1a.fs" />
+    <Compile Include="createinstance2.fs" />
+    <Compile Include="CreateInstance5.fs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="PersonInfo\PersonInfo.fsproj"/>
+  </ItemGroup>
+
+
+</Project>
@@ -0,0 +1,22 @@
+module createinstanceex2
+// <Snippet4>
+open System
+
+let chars = [| 'a' .. 'f' |]
+
+let arguments =
+    [| chars
+       chars[1..4]
+       Array.create 20 chars[1] |]
+
+for args in arguments do
+    let result =
+        Activator.CreateInstance(typeof<string>, args)
+
+    printfn $"{result.GetType().Name}: {result}"
+
+// The example displays the following output:
+//    String: abcdef
+//    String: bcde
+//    String: bbbbbbbbbbbbbbbbbbbb
+// </Snippet4>
@@ -0,0 +1,13 @@
+module createinstanceex1
+
+// <Snippet2>
+open System
+
+let handle = Activator.CreateInstance("PersonInfo", "Person")
+let p = handle.Unwrap() :?> Person
+p.Name <- "Samuel"
+printfn $"{p}"
+
+// The example displays the following output:
+//        Samuel
+// </Snippet2>
@@ -0,0 +1,24 @@
+module createinstanceex1a
+
+// <Snippet3>
+open System
+
+let handle =
+    Activator.CreateInstance("PersonInfo", "Person")
+
+let p = handle.Unwrap()
+let t = p.GetType()
+let prop = t.GetProperty "Name"
+
+if not (isNull prop) then
+    prop.SetValue(p, "Samuel")
+
+let method = t.GetMethod "ToString"
+let retVal = method.Invoke(p, null)
+
+if not (isNull retVal) then
+    printfn $"{retVal}"
+
+// The example displays the following output:
+//        Samuel
+// </Snippet3>
@@ -0,0 +1,11 @@
+namespace global
+
+// <Snippet1>
+type Person(name) =
+    member val Name = name with get, set
+
+    override this.ToString() = this.Name
+
+    new () = Person Unchecked.defaultof<string>
+
+// </Snippet1>
@@ -90,6 +90,7 @@
 
  :::code language="cpp" source="~/samples/snippets/cpp/VS_Snippets_CLR/ActivatorX/cpp/ActivatorX.cpp" id="Snippet1":::
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR/ActivatorX/cs/ActivatorX.cs" id="Snippet1":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR/ActivatorX/fs/ActivatorX.fs" id="Snippet1":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR/ActivatorX/VB/ActivatorX.vb" id="Snippet1":::  
 
  ]]></format>
@@ -404,6 +405,7 @@
 
  :::code language="cpp" source="~/samples/snippets/cpp/VS_Snippets_CLR/ActivatorX/cpp/source2.cpp" id="Snippet4":::
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR/ActivatorX/cs/source2.cs" interactive="try-dotnet" id="Snippet4":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR/ActivatorX/fs/source2.fs" id="Snippet4":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR/ActivatorX/VB/source2.vb" id="Snippet4":::
 
  ]]></format>
@@ -571,16 +573,19 @@ Note: In <see href="https://go.microsoft.com/fwlink/?LinkID=247912">.NET for Win
  The following example defines a class named `Person` in an assembly named `PersonInfo`. Note that the `Person` class has two constructors, one of which is parameterless.  
 
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_System/system.activator.createinstance/cs/personinfo.cs" id="Snippet1":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR_System/system.activator.createinstance/fs/personinfo.fs" id="Snippet1":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.activator.createinstance/vb/personinfo.vb" id="Snippet1":::  
 
  The following example calls the <xref:System.Activator.CreateInstance%28System.String%2CSystem.String%29> method to instantiate the `Person` class. It requires a reference to PersonInfo.dll to be added to the project. Because the <xref:System.Activator.CreateInstance%28System.String%2CSystem.String%29> method calls the `Person` class parameterless constructor,  the example assigns a value to its `Name` property.  
 
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_System/system.activator.createinstance/cs/createinstanceex1.cs" id="Snippet2":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR_System/system.activator.createinstance/fs/createinstanceex1.fs" id="Snippet2":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.activator.createinstance/vb/createinstanceex1.vb" id="Snippet2":::  
 
  However, <xref:System.Activator.CreateInstance%2A> is frequently called to instantiate a type that crosses machine boundaries or that is not known at design time. In this case, you cannot include a reference to the assembly in the project and cannot make early-bound calls to the type's members. To work around this limitation, the following example uses the <xref:System.Activator.CreateInstance%2A> method along with reflection to assign a value to the `Person` object's `Name` property and to display its value.  
 
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_System/system.activator.createinstance/cs/createinstanceex1a.cs" id="Snippet3":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR_System/system.activator.createinstance/fs/createinstanceex1a.fs" id="Snippet3":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.activator.createinstance/vb/createinstanceex1a.vb" id="Snippet3":::  
 
  ]]></format>
@@ -776,11 +781,13 @@ Note: In <see href="https://go.microsoft.com/fwlink/?LinkID=247912">.NET for Win
  The following example calls the  <xref:System.Activator.CreateInstance%28System.Type%2CSystem.Object%5B%5D%29> method to create a <xref:System.String> object. It calls the <xref:System.String.%23ctor%28System.Char%5B%5D%2CSystem.Int32%2CSystem.Int32%29?displayProperty=nameWithType> constructor to instantiate a string that contains ten elements from a character array starting at the fourteenth position.  
 
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_System/system.activator.createinstance/cs/CreateInstance5.cs" interactive="try-dotnet" id="Snippet5":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR_System/system.activator.createinstance/fs/CreateInstance5.fs" id="Snippet5":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.activator.createinstance/vb/CreateInstance5.vb" id="Snippet5":::
 
  The following example creates a jagged array whose elements are arguments to be passed to a <xref:System.String> constructor. The example then passes each array to the <xref:System.Activator.CreateInstance%28System.Type%2CSystem.Object%5B%5D%29> method to invoke the appropriate string constructor.  
 
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_System/system.activator.createinstance/cs/createinstance2.cs" interactive="try-dotnet" id="Snippet4":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR_System/system.activator.createinstance/fs/createinstance2.fs" id="Snippet4":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.activator.createinstance/vb/createinstance2.vb" id="Snippet4":::
 
  ]]></format>
@@ -1812,6 +1819,7 @@ Note: In <see href="https://go.microsoft.com/fwlink/?LinkID=247912">.NET for Win
 
  :::code language="cpp" source="~/samples/snippets/cpp/VS_Snippets_CLR_System/system.activation.createinstance~~1/cpp/remarks.cpp" id="Snippet1":::
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR_System/system.activation.createinstance~~1/cs/remarks.cs" id="Snippet1":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR_System/system.activation.createinstance~~1/fs/remarks.fs" id="Snippet1":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR_System/system.activation.createinstance~~1/vb/remarks.vb" id="Snippet1":::  
 
  In general, there is no use for the <xref:System.Activator.CreateInstance%60%601> generic method in application code, because the type must be known at compile time. If the type is known at compile time, normal instantiation syntax can be used (`new` operator in C#, `New` in Visual Basic, `gcnew` in C++). If the type is not known at compile time, you can call a non-generic overload of <xref:System.Activator.CreateInstance%2A>.  
@@ -1899,6 +1907,7 @@ Note: In <see href="https://go.microsoft.com/fwlink/?LinkID=247912">.NET for Win
 
  :::code language="cpp" source="~/samples/snippets/cpp/VS_Snippets_CLR/ActivatorX/cpp/ActivatorX.cpp" id="Snippet3":::
  :::code language="csharp" source="~/samples/snippets/csharp/VS_Snippets_CLR/ActivatorX/cs/ActivatorX.cs" id="Snippet3":::
+ :::code language="fsharp" source="~/samples/snippets/fsharp/VS_Snippets_CLR/ActivatorX/fs/ActivatorX.fs" id="Snippet3":::
  :::code language="vb" source="~/samples/snippets/visualbasic/VS_Snippets_CLR/ActivatorX/VB/ActivatorX.vb" id="Snippet3":::  
 
  ]]></format>