Revert "Remove FormObject.cs and FormObjectCollection.cs (#19383)" (#19387)

This reverts commit 190c99a416.

src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/Common/WebRequestPSCmdlet.Common.cs

@@ -1157,6 +1157,9 @@ namespace Microsoft.PowerShell.Commands
 
                 switch (content)
                 {
+                    case FormObject form:
+                        SetRequestContent(request, form.Fields);
+                        break;
                     case IDictionary dictionary when request.Method != HttpMethod.Get:
                         SetRequestContent(request, dictionary);
                         break;

src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/FormObject.cs

@@ -0,0 +1,55 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.Collections.Generic;
+
+namespace Microsoft.PowerShell.Commands
+{
+    /// <summary>
+    /// FormObject used in HtmlWebResponseObject.
+    /// </summary>
+    public class FormObject
+    {
+        /// <summary>
+        /// Gets the Id property.
+        /// </summary>
+        public string Id { get; }
+
+        /// <summary>
+        /// Gets the Method property.
+        /// </summary>
+        public string Method { get; }
+
+        /// <summary>
+        /// Gets the Action property.
+        /// </summary>
+        public string Action { get; }
+
+        /// <summary>
+        /// Gets the Fields property.
+        /// </summary>
+        public Dictionary<string, string> Fields { get; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FormObject"/> class.
+        /// </summary>
+        /// <param name="id"></param>
+        /// <param name="method"></param>
+        /// <param name="action"></param>
+        public FormObject(string id, string method, string action)
+        {
+            Id = id;
+            Method = method;
+            Action = action;
+            Fields = new Dictionary<string, string>();
+        }
+
+        internal void AddField(string key, string value)
+        {
+            if (key is not null && !Fields.TryGetValue(key, out string test))
+            {
+                Fields[key] = value;
+            }
+        }
+    }
+}

src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/FormObjectCollection.cs

@@ -0,0 +1,37 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using System.Collections.ObjectModel;
+
+namespace Microsoft.PowerShell.Commands
+{
+    /// <summary>
+    /// FormObjectCollection used in HtmlWebResponseObject.
+    /// </summary>
+    public class FormObjectCollection : Collection<FormObject>
+    {
+        /// <summary>
+        /// Gets the FormObject from the key.
+        /// </summary>
+        /// <param name="key"></param>
+        /// <returns></returns>
+        public FormObject this[string key]
+        {
+            get
+            {
+                FormObject form = null;
+                foreach (FormObject f in this)
+                {
+                    if (string.Equals(key, f.Id, StringComparison.OrdinalIgnoreCase))
+                    {
+                        form = f;
+                        break;
+                    }
+                }
+
+                return form;
+            }
+        }
+    }
+}