From c9226559253ae194dc4bbc27614403e8dd6df442 Mon Sep 17 00:00:00 2001
From: Simon Oxtoby <simonoxtoby@gmail.com>
Date: Fri, 3 Jan 2020 09:59:10 +1000
Subject: [PATCH] Adding multi-select block elements

---
 SlackNet/Blocks/ActionElement.cs              | 24 +++++++++++++
 SlackNet/Blocks/Button.cs                     | 13 +------
 SlackNet/Blocks/ChannelMultiSelectAction.cs   | 10 ++++++
 SlackNet/Blocks/ChannelMultiSelectMenu.cs     | 23 ++++++++++++
 SlackNet/Blocks/ChannelSelectMenu.cs          | 18 +---------
 .../Blocks/ConversationMultiSelectAction.cs   | 10 ++++++
 .../Blocks/ConversationMultiSelectMenu.cs     | 23 ++++++++++++
 SlackNet/Blocks/ConversationSelectMenu.cs     | 18 +---------
 SlackNet/Blocks/DatePicker.cs                 | 13 +------
 SlackNet/Blocks/ExternalMultiSelectAction.cs  | 10 ++++++
 SlackNet/Blocks/ExternalMultiSelectMenu.cs    | 26 ++++++++++++++
 SlackNet/Blocks/ExternalSelectMenu.cs         | 24 +------------
 SlackNet/Blocks/ExternalSelectMenuBase.cs     | 13 +++++++
 SlackNet/Blocks/IActionElement.cs             |  8 -----
 SlackNet/Blocks/OverflowMenu.cs               | 13 +------
 SlackNet/Blocks/SelectMenuBase.cs             | 12 +++++++
 SlackNet/Blocks/StaticMultiSelectAction.cs    | 10 ++++++
 SlackNet/Blocks/StaticMultiSelectMenu.cs      | 25 +++++++++++++
 SlackNet/Blocks/StaticSelectMenu.cs           | 36 ++-----------------
 SlackNet/Blocks/StaticSelectMenuBase.cs       | 21 +++++++++++
 SlackNet/Blocks/UserMultiSelectAction.cs      | 10 ++++++
 SlackNet/Blocks/UserMultiSelectMenu.cs        | 23 ++++++++++++
 SlackNet/Blocks/UserSelectMenu.cs             | 18 +---------
 23 files changed, 250 insertions(+), 151 deletions(-)
 create mode 100644 SlackNet/Blocks/ActionElement.cs
 create mode 100644 SlackNet/Blocks/ChannelMultiSelectAction.cs
 create mode 100644 SlackNet/Blocks/ChannelMultiSelectMenu.cs
 create mode 100644 SlackNet/Blocks/ConversationMultiSelectAction.cs
 create mode 100644 SlackNet/Blocks/ConversationMultiSelectMenu.cs
 create mode 100644 SlackNet/Blocks/ExternalMultiSelectAction.cs
 create mode 100644 SlackNet/Blocks/ExternalMultiSelectMenu.cs
 create mode 100644 SlackNet/Blocks/ExternalSelectMenuBase.cs
 delete mode 100644 SlackNet/Blocks/IActionElement.cs
 create mode 100644 SlackNet/Blocks/SelectMenuBase.cs
 create mode 100644 SlackNet/Blocks/StaticMultiSelectAction.cs
 create mode 100644 SlackNet/Blocks/StaticMultiSelectMenu.cs
 create mode 100644 SlackNet/Blocks/StaticSelectMenuBase.cs
 create mode 100644 SlackNet/Blocks/UserMultiSelectAction.cs
 create mode 100644 SlackNet/Blocks/UserMultiSelectMenu.cs

diff --git a/SlackNet/Blocks/ActionElement.cs b/SlackNet/Blocks/ActionElement.cs
new file mode 100644
index 0000000..71789ba
--- /dev/null
+++ b/SlackNet/Blocks/ActionElement.cs
@@ -0,0 +1,24 @@
+namespace SlackNet.Blocks
+{
+    public interface IActionElement
+    {
+        string Type { get; }
+        string ActionId { get; set; }
+    }
+
+    public abstract class ActionElement : BlockElement, IActionElement
+    {
+        protected ActionElement(string type) : base(type) { }
+
+        /// <summary>
+        /// An identifier for this action. You can use this when you receive an interaction payload to identify the source of the action.
+        /// Should be unique among all other <see cref="ActionId"/>s used elsewhere by your app. 
+        /// </summary>
+        public string ActionId { get; set; }
+
+        /// <summary>
+        /// Defines an optional confirmation dialog that appears after the element is activated.
+        /// </summary>
+        public ConfirmationDialog Confirm { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/Button.cs b/SlackNet/Blocks/Button.cs
index 0482452..d04d3b2 100644
--- a/SlackNet/Blocks/Button.cs
+++ b/SlackNet/Blocks/Button.cs
@@ -4,7 +4,7 @@
     /// An interactive element that inserts a button. The button can be a trigger for anything from opening a simple link to starting a complex workflow.
     /// </summary>
     [SlackType("button")]
-    public class Button : BlockElement, IActionElement
+    public class Button : ActionElement
     {
         public Button() : base("button") { }
 
@@ -30,17 +30,6 @@ public Button() : base("button") { }
         /// </summary>
         [IgnoreIfDefault]
         public ButtonStyle Style { get; set; }
-
-        /// <summary>
-        /// Defines an optional confirmation dialog after the button is clicked.
-        /// </summary>
-        public ConfirmationDialog Confirm { get; set; }
-
-        /// <summary>
-        /// An identifier for this action. You can use this when you receive an interaction payload to identify the source of the action.
-        /// Should be unique among all other <see cref="ActionId"/>s used elsewhere by your app. 
-        /// </summary>
-        public string ActionId { get; set; }
     }
 
     public enum ButtonStyle
diff --git a/SlackNet/Blocks/ChannelMultiSelectAction.cs b/SlackNet/Blocks/ChannelMultiSelectAction.cs
new file mode 100644
index 0000000..1b94fff
--- /dev/null
+++ b/SlackNet/Blocks/ChannelMultiSelectAction.cs
@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+
+namespace SlackNet.Blocks
+{
+    [SlackType("multi_channels_select")]
+    public class ChannelMultiSelectAction
+    {
+        public IList<string> SelectedChannels { get; set; } = new List<string>();
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/ChannelMultiSelectMenu.cs b/SlackNet/Blocks/ChannelMultiSelectMenu.cs
new file mode 100644
index 0000000..54b867d
--- /dev/null
+++ b/SlackNet/Blocks/ChannelMultiSelectMenu.cs
@@ -0,0 +1,23 @@
+using System.Collections.Generic;
+
+namespace SlackNet.Blocks
+{
+    /// <summary>
+    /// This multi-select menu will populate its options with a list of public channels visible to the current user in the active workspace.
+    /// </summary>
+    [SlackType("multi_channels_select")]
+    public class ChannelMultiSelectMenu : SelectMenuBase
+    {
+        public ChannelMultiSelectMenu() : base("multi_channels_select") { }
+
+        /// <summary>
+        /// A list of one or more IDs of any valid public channel to be pre-selected when the menu loads.
+        /// </summary>
+        public IList<string> InitialChannels { get; set; } = new List<string>();
+
+        /// <summary>
+        /// Specifies the maximum number of items that can be selected in the menu. Minimum number is 1.
+        /// </summary>
+        public int? MaxSelectedItems { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/ChannelSelectMenu.cs b/SlackNet/Blocks/ChannelSelectMenu.cs
index c90cc67..a6fb6ca 100644
--- a/SlackNet/Blocks/ChannelSelectMenu.cs
+++ b/SlackNet/Blocks/ChannelSelectMenu.cs
@@ -4,29 +4,13 @@
     /// This select menu will populate its options with a list of public channels visible to the current user in the active workspace.
     /// </summary>
     [SlackType("channels_select")]
-    public class ChannelSelectMenu : BlockElement, IActionElement
+    public class ChannelSelectMenu : SelectMenuBase
     {
         public ChannelSelectMenu() : base("channels_select") { }
 
-        /// <summary>
-        /// A plain text object that defines the placeholder text shown on the menu. 
-        /// </summary>
-        public PlainText Placeholder { get; set; }
-
         /// <summary>
         /// The ID of any valid public channel to be pre-selected when the menu loads.
         /// </summary>
         public string InitialChannel { get; set; }
-
-        /// <summary>
-        /// Defines an optional confirmation dialog that appears after a menu item is selected.
-        /// </summary>
-        public ConfirmationDialog Confirm { get; set; }
-
-        /// <summary>
-        /// An identifier for this action. You can use this when you receive an interaction payload to identify the source of the action.
-        /// Should be unique among all other <see cref="ActionId"/>s used elsewhere by your app. 
-        /// </summary>
-        public string ActionId { get; set; }
     }
 }
\ No newline at end of file
diff --git a/SlackNet/Blocks/ConversationMultiSelectAction.cs b/SlackNet/Blocks/ConversationMultiSelectAction.cs
new file mode 100644
index 0000000..706cef0
--- /dev/null
+++ b/SlackNet/Blocks/ConversationMultiSelectAction.cs
@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+
+namespace SlackNet.Blocks
+{
+    [SlackType("multi_conversations_select")]
+    public class ConversationMultiSelectAction
+    {
+        public IList<string> SelectedConversations { get; set; } = new List<string>();
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/ConversationMultiSelectMenu.cs b/SlackNet/Blocks/ConversationMultiSelectMenu.cs
new file mode 100644
index 0000000..aa1f161
--- /dev/null
+++ b/SlackNet/Blocks/ConversationMultiSelectMenu.cs
@@ -0,0 +1,23 @@
+using System.Collections.Generic;
+
+namespace SlackNet.Blocks
+{
+    /// <summary>
+    /// This multi-select menu will populate its options with a list of public and private channels, DMs, and MPIMs visible to the current user in the active workspace.
+    /// </summary>
+    [SlackType("multi_conversations_select")]
+    public class ConversationMultiSelectMenu : SelectMenuBase
+    {
+        public ConversationMultiSelectMenu() : base("multi_conversations_select") { }
+
+        /// <summary>
+        /// A list of one or more IDs of any valid conversations to be pre-selected when the menu loads.
+        /// </summary>
+        public IList<string> InitialConversations { get; set; } = new List<string>();
+
+        /// <summary>
+        /// Specifies the maximum number of items that can be selected in the menu. Minimum number is 1.
+        /// </summary>
+        public int? MaxSelectedItems { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/ConversationSelectMenu.cs b/SlackNet/Blocks/ConversationSelectMenu.cs
index 1c31f06..23300e1 100644
--- a/SlackNet/Blocks/ConversationSelectMenu.cs
+++ b/SlackNet/Blocks/ConversationSelectMenu.cs
@@ -4,29 +4,13 @@
     /// This select menu will populate its options with a list of public and private channels, DMs, and MPIMs visible to the current user in the active workspace.
     /// </summary>
     [SlackType("conversations_select")]
-    public class ConversationSelectMenu : BlockElement, IActionElement
+    public class ConversationSelectMenu : SelectMenuBase
     {
         public ConversationSelectMenu() : base("conversations_select") { }
 
-        /// <summary>
-        /// A plain text object that defines the placeholder text shown on the menu. 
-        /// </summary>
-        public PlainText Placeholder { get; set; }
-
         /// <summary>
         /// The ID of any valid conversation to be pre-selected when the menu loads.
         /// </summary>
         public string InitialConversation { get; set; }
-
-        /// <summary>
-        /// Defines an optional confirmation dialog that appears after a menu item is selected.
-        /// </summary>
-        public ConfirmationDialog Confirm { get; set; }
-
-        /// <summary>
-        /// An identifier for this action. You can use this when you receive an interaction payload to identify the source of the action.
-        /// Should be unique among all other <see cref="ActionId"/>s used elsewhere by your app. 
-        /// </summary>
-        public string ActionId { get; set; }
     }
 }
\ No newline at end of file
diff --git a/SlackNet/Blocks/DatePicker.cs b/SlackNet/Blocks/DatePicker.cs
index 2f50748..5d181bf 100644
--- a/SlackNet/Blocks/DatePicker.cs
+++ b/SlackNet/Blocks/DatePicker.cs
@@ -7,7 +7,7 @@ namespace SlackNet.Blocks
     /// Date picker elements can be used inside of section and actions blocks.
     /// </summary>
     [SlackType("datepicker")]
-    public class DatePicker : BlockElement, IActionElement
+    public class DatePicker : ActionElement
     {
         public DatePicker() : base("datepicker") { }
 
@@ -20,16 +20,5 @@ public DatePicker() : base("datepicker") { }
         /// The initial date that is selected when the element is loaded.
         /// </summary>
         public DateTime? InitialDate { get; set; }
-
-        /// <summary>
-        /// Defines an optional confirmation dialog that appears after a menu item is selected.
-        /// </summary>
-        public ConfirmationDialog Confirm { get; set; }
-
-        /// <summary>
-        /// An identifier for this action. You can use this when you receive an interaction payload to identify the source of the action.
-        /// Should be unique among all other <see cref="ActionId"/>s used elsewhere by your app. 
-        /// </summary>
-        public string ActionId { get; set; }
     }
 }
\ No newline at end of file
diff --git a/SlackNet/Blocks/ExternalMultiSelectAction.cs b/SlackNet/Blocks/ExternalMultiSelectAction.cs
new file mode 100644
index 0000000..64b0e80
--- /dev/null
+++ b/SlackNet/Blocks/ExternalMultiSelectAction.cs
@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+
+namespace SlackNet.Blocks
+{
+    [SlackType("multi_external_select")]
+    public class ExternalMultiSelectAction
+    {
+        public IList<Option> SelectedOptions { get; set; } = new List<Option>();
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/ExternalMultiSelectMenu.cs b/SlackNet/Blocks/ExternalMultiSelectMenu.cs
new file mode 100644
index 0000000..dd422d9
--- /dev/null
+++ b/SlackNet/Blocks/ExternalMultiSelectMenu.cs
@@ -0,0 +1,26 @@
+using System.Collections.Generic;
+using SlackNet.Interaction;
+
+namespace SlackNet.Blocks
+{
+    /// <summary>
+    /// This menu will load its options from an external data source, allowing for a dynamic list of options.
+    /// </summary>
+    [SlackType("multi_external_select")]
+    public class ExternalMultiSelectMenu : ExternalSelectMenuBase
+    {
+        public ExternalMultiSelectMenu() : base("multi_external_select") { }
+
+        /// <summary>
+        /// A list of <see cref="Option"/>s that exactly match one or more of the options within the <see cref="BlockOptionsResponse.Options"/>
+        /// or <see cref="BlockOptionsResponse.OptionGroups"/> loaded from the external data source.
+        /// These options will be selected when the menu initially loads.
+        /// </summary>
+        public IList<Option> InitialOptions { get; set; } = new List<Option>();
+
+        /// <summary>
+        /// Specifies the maximum number of items that can be selected in the menu. Minimum number is 1.
+        /// </summary>
+        public int? MaxSelectedItems { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/ExternalSelectMenu.cs b/SlackNet/Blocks/ExternalSelectMenu.cs
index 3ec3bae..332e38a 100644
--- a/SlackNet/Blocks/ExternalSelectMenu.cs
+++ b/SlackNet/Blocks/ExternalSelectMenu.cs
@@ -6,37 +6,15 @@ namespace SlackNet.Blocks
     /// This select menu will load its options from an external data source, allowing for a dynamic list of options.
     /// </summary>
     [SlackType("external_select")]
-    public class ExternalSelectMenu : BlockElement, IActionElement
+    public class ExternalSelectMenu : ExternalSelectMenuBase
     {
         public ExternalSelectMenu() : base("external_select") { }
 
-        /// <summary>
-        /// A plain text object that defines the placeholder text shown on the menu. 
-        /// </summary>
-        public PlainText Placeholder { get; set; }
-
         /// <summary>
         /// A single <see cref="Option"/> that exactly matches one of the options within the <see cref="BlockOptionsResponse.Options"/>
         /// or <see cref="BlockOptionsResponse.OptionGroups"/> loaded from the external data source.
         /// This option will be selected when the menu initially loads.
         /// </summary>
         public Option InitialOption { get; set; }
-
-        /// <summary>
-        /// When the typeahead field is used, a request will be sent on every character change.
-        /// If you prefer fewer requests or more fully ideated queries, use this to tell Slack the fewest number of typed characters required before dispatch.
-        /// </summary>
-        public int? MinQueryLength { get; set; }
-
-        /// <summary>
-        /// Defines an optional confirmation dialog that appears after a menu item is selected.
-        /// </summary>
-        public ConfirmationDialog Confirm { get; set; }
-
-        /// <summary>
-        /// An identifier for this action. You can use this when you receive an interaction payload to identify the source of the action.
-        /// Should be unique among all other <see cref="ActionId"/>s used elsewhere by your app. 
-        /// </summary>
-        public string ActionId { get; set; }
     }
 }
\ No newline at end of file
diff --git a/SlackNet/Blocks/ExternalSelectMenuBase.cs b/SlackNet/Blocks/ExternalSelectMenuBase.cs
new file mode 100644
index 0000000..9eae3f5
--- /dev/null
+++ b/SlackNet/Blocks/ExternalSelectMenuBase.cs
@@ -0,0 +1,13 @@
+namespace SlackNet.Blocks
+{
+    public abstract class ExternalSelectMenuBase : SelectMenuBase
+    {
+        protected ExternalSelectMenuBase(string type) : base(type) { }
+
+        /// <summary>
+        /// When the typeahead field is used, a request will be sent on every character change.
+        /// If you prefer fewer requests or more fully ideated queries, use this to tell Slack the fewest number of typed characters required before dispatch.
+        /// </summary>
+        public int? MinQueryLength { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/IActionElement.cs b/SlackNet/Blocks/IActionElement.cs
deleted file mode 100644
index fb0b7de..0000000
--- a/SlackNet/Blocks/IActionElement.cs
+++ /dev/null
@@ -1,8 +0,0 @@
-namespace SlackNet.Blocks
-{
-    public interface IActionElement
-    {
-        string Type { get; }
-        string ActionId { get; set; }
-    }
-}
\ No newline at end of file
diff --git a/SlackNet/Blocks/OverflowMenu.cs b/SlackNet/Blocks/OverflowMenu.cs
index f9e3ed2..5890a49 100644
--- a/SlackNet/Blocks/OverflowMenu.cs
+++ b/SlackNet/Blocks/OverflowMenu.cs
@@ -12,7 +12,7 @@ namespace SlackNet.Blocks
     /// You can also specify simple URL links as overflow menu options, instead of actions.
     /// </summary>
     [SlackType("overflow")]
-    public class OverflowMenu : BlockElement, IActionElement
+    public class OverflowMenu : ActionElement
     {
         public OverflowMenu() : base("overflow") { }
 
@@ -20,16 +20,5 @@ public OverflowMenu() : base("overflow") { }
         /// A list of option objects to display in the menu.
         /// </summary>
         public IList<OverflowOption> Options { get; set; } = new List<OverflowOption>();
-
-        /// <summary>
-        /// Defines an optional confirmation dialog that appears after a menu item is selected.
-        /// </summary>
-        public ConfirmationDialog Confirm { get; set; }
-
-        /// <summary>
-        /// An identifier for this action. You can use this when you receive an interaction payload to identify the source of the action.
-        /// Should be unique among all other <see cref="ActionId"/>s used elsewhere by your app. 
-        /// </summary>
-        public string ActionId { get; set; }
     }
 }
\ No newline at end of file
diff --git a/SlackNet/Blocks/SelectMenuBase.cs b/SlackNet/Blocks/SelectMenuBase.cs
new file mode 100644
index 0000000..e324a67
--- /dev/null
+++ b/SlackNet/Blocks/SelectMenuBase.cs
@@ -0,0 +1,12 @@
+namespace SlackNet.Blocks
+{
+    public abstract class SelectMenuBase : ActionElement
+    {
+        protected SelectMenuBase(string type) : base(type) { }
+
+        /// <summary>
+        /// A plain text object that defines the placeholder text shown on the menu. 
+        /// </summary>
+        public PlainText Placeholder { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/StaticMultiSelectAction.cs b/SlackNet/Blocks/StaticMultiSelectAction.cs
new file mode 100644
index 0000000..18ce11a
--- /dev/null
+++ b/SlackNet/Blocks/StaticMultiSelectAction.cs
@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+
+namespace SlackNet.Blocks
+{
+    [SlackType("multi_static_select")]
+    public class StaticMultiSelectAction : BlockAction
+    {
+        public IList<Option> SelectedOptions { get; set; } = new List<Option>();
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/StaticMultiSelectMenu.cs b/SlackNet/Blocks/StaticMultiSelectMenu.cs
new file mode 100644
index 0000000..33cfbaf
--- /dev/null
+++ b/SlackNet/Blocks/StaticMultiSelectMenu.cs
@@ -0,0 +1,25 @@
+using System.Collections.Generic;
+
+namespace SlackNet.Blocks
+{
+    /// <summary>
+    /// A multi-select menu allows a user to select multiple items from a list of options.
+    /// </summary>
+    [SlackType("multi_static_select")]
+    public class StaticMultiSelectMenu : StaticSelectMenuBase
+    {
+        public StaticMultiSelectMenu() : base("multi_static_select") { }
+
+        /// <summary>
+        /// A list of <see cref="Option"/>s that exactly match one or more of the options within <see cref="StaticSelectMenuBase.Options"/> or <see cref="StaticSelectMenuBase.OptionGroups"/>.
+        /// These options will be selected when the menu initially loads.
+        /// </summary>
+        [IgnoreIfEmpty]
+        public IList<Option> InitialOptions { get; set; } = new List<Option>();
+
+        /// <summary>
+        /// Specifies the maximum number of items that can be selected in the menu. Minimum number is 1.
+        /// </summary>
+        public int? MaxSelectedItems { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/StaticSelectMenu.cs b/SlackNet/Blocks/StaticSelectMenu.cs
index 0b12f05..c19ceee 100644
--- a/SlackNet/Blocks/StaticSelectMenu.cs
+++ b/SlackNet/Blocks/StaticSelectMenu.cs
@@ -1,47 +1,17 @@
-using System.Collections.Generic;
-
-namespace SlackNet.Blocks
+namespace SlackNet.Blocks
 {
     /// <summary>
     /// This is the simplest form of select menu, with a static list of options passed in when defining the element.
     /// </summary>
     [SlackType("static_select")]
-    public class StaticSelectMenu : BlockElement, IActionElement
+    public class StaticSelectMenu : StaticSelectMenuBase
     {
         public StaticSelectMenu() : base("static_select") { }
 
         /// <summary>
-        /// A plain text object that defines the placeholder text shown on the menu. 
-        /// </summary>
-        public PlainText Placeholder { get; set; }
-
-        /// <summary>
-        /// An array of <see cref="Option"/> objects. If <see cref="OptionGroups"/> is specified, this field should not be.
-        /// </summary>
-        [IgnoreIfEmpty]
-        public IList<Option> Options { get; set; } = new List<Option>();
-
-        /// <summary>
-        /// An array of <see cref="OptionGroup"/> objects. If <see cref="Options"/> is specified, this field should not be.
-        /// </summary>
-        [IgnoreIfEmpty]
-        public IList<OptionGroup> OptionGroups { get; set; } = new List<OptionGroup>();
-
-        /// <summary>
-        /// A single <see cref="Option"/> that exactly matches one of the options within <see cref="Options"/> or <see cref="OptionGroups"/>.
+        /// A single <see cref="Option"/> that exactly matches one of the options within <see cref="StaticSelectMenuBase.Options"/> or <see cref="StaticSelectMenuBase.OptionGroups"/>.
         /// This option will be selected when the menu initially loads.
         /// </summary>
         public Option InitialOption { get; set; }
-
-        /// <summary>
-        /// Defines an optional confirmation dialog that appears after a menu item is selected.
-        /// </summary>
-        public ConfirmationDialog Confirm { get; set; }
-
-        /// <summary>
-        /// An identifier for this action. You can use this when you receive an interaction payload to identify the source of the action.
-        /// Should be unique among all other <see cref="ActionId"/>s used elsewhere by your app. 
-        /// </summary>
-        public string ActionId { get; set; }
     }
 }
\ No newline at end of file
diff --git a/SlackNet/Blocks/StaticSelectMenuBase.cs b/SlackNet/Blocks/StaticSelectMenuBase.cs
new file mode 100644
index 0000000..523335e
--- /dev/null
+++ b/SlackNet/Blocks/StaticSelectMenuBase.cs
@@ -0,0 +1,21 @@
+using System.Collections.Generic;
+
+namespace SlackNet.Blocks
+{
+    public abstract class StaticSelectMenuBase : SelectMenuBase
+    {
+        protected StaticSelectMenuBase(string type) : base(type) { }
+
+        /// <summary>
+        /// An array of <see cref="Option"/> objects. If <see cref="OptionGroups"/> is specified, this field should not be.
+        /// </summary>
+        [IgnoreIfEmpty]
+        public IList<Option> Options { get; set; } = new List<Option>();
+
+        /// <summary>
+        /// An array of <see cref="OptionGroup"/> objects. If <see cref="Options"/> is specified, this field should not be.
+        /// </summary>
+        [IgnoreIfEmpty]
+        public IList<OptionGroup> OptionGroups { get; set; } = new List<OptionGroup>();
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/UserMultiSelectAction.cs b/SlackNet/Blocks/UserMultiSelectAction.cs
new file mode 100644
index 0000000..a2759ba
--- /dev/null
+++ b/SlackNet/Blocks/UserMultiSelectAction.cs
@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+
+namespace SlackNet.Blocks
+{
+    [SlackType("multi_users_select")]
+    public class UserMultiSelectAction
+    {
+        public IList<string> SelectedUsers { get; set; } = new List<string>();
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/UserMultiSelectMenu.cs b/SlackNet/Blocks/UserMultiSelectMenu.cs
new file mode 100644
index 0000000..6d21d56
--- /dev/null
+++ b/SlackNet/Blocks/UserMultiSelectMenu.cs
@@ -0,0 +1,23 @@
+using System.Collections.Generic;
+
+namespace SlackNet.Blocks
+{
+    /// <summary>
+    /// This multi-select menu will populate its options with a list of Slack users visible to the current user in the active workspace.
+    /// </summary>
+    [SlackType("multi_users_select")]
+    public class UserMultiSelectMenu : SelectMenuBase
+    {
+        public UserMultiSelectMenu() : base("multi_users_select") { }
+
+        /// <summary>
+        /// A list of user IDs of any valid users to be pre-selected when the menu loads.
+        /// </summary>
+        public IList<string> InitialUsers { get; set; } = new List<string>();
+
+        /// <summary>
+        /// Specifies the maximum number of items that can be selected in the menu. Minimum number is 1.
+        /// </summary>
+        public int? MaxSelectedItems { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/SlackNet/Blocks/UserSelectMenu.cs b/SlackNet/Blocks/UserSelectMenu.cs
index 684881e..6e24ae0 100644
--- a/SlackNet/Blocks/UserSelectMenu.cs
+++ b/SlackNet/Blocks/UserSelectMenu.cs
@@ -4,29 +4,13 @@
     /// This select menu will populate its options with a list of Slack users visible to the current user in the active workspace.
     /// </summary>
     [SlackType("users_select")]
-    public class UserSelectMenu : BlockElement, IActionElement
+    public class UserSelectMenu : SelectMenuBase
     {
         public UserSelectMenu() : base("users_select") { }
 
-        /// <summary>
-        /// A plain text object that defines the placeholder text shown on the menu. 
-        /// </summary>
-        public PlainText Placeholder { get; set; }
-
         /// <summary>
         /// The user ID of any valid user to be pre-selected when the menu loads.
         /// </summary>
         public string InitialUser { get; set; }
-
-        /// <summary>
-        /// Defines an optional confirmation dialog that appears after a menu item is selected.
-        /// </summary>
-        public ConfirmationDialog Confirm { get; set; }
-
-        /// <summary>
-        /// An identifier for this action. You can use this when you receive an interaction payload to identify the source of the action.
-        /// Should be unique among all other <see cref="ActionId"/>s used elsewhere by your app. 
-        /// </summary>
-        public string ActionId { get; set; }
     }
 }
\ No newline at end of file