Add TaskDialog accessibility sample (#3537)

src/System.Windows.Forms/tests/AccessibilityTests/DialogsTesting.Designer.cs

@@ -33,6 +33,7 @@
             this.FolderBrowserDialog = new System.Windows.Forms.Button();
             this.OpenFileDialog = new System.Windows.Forms.Button();
             this.SaveFileDialog = new System.Windows.Forms.Button();
+            this.StartTaskDialog = new System.Windows.Forms.Button();
             this.SuspendLayout();
             // 
             // ColorDialog
@@ -85,11 +86,22 @@
             this.SaveFileDialog.UseVisualStyleBackColor = true;
             this.SaveFileDialog.Click += new System.EventHandler(this.SaveFileDialog_Click);
             // 
+            // TaskDialog
+            // 
+            this.StartTaskDialog.Location = new System.Drawing.Point(428, 34);
+            this.StartTaskDialog.Name = "StartTaskDialog";
+            this.StartTaskDialog.Size = new System.Drawing.Size(98, 23);
+            this.StartTaskDialog.TabIndex = 5;
+            this.StartTaskDialog.Text = "Open TaskDialog";
+            this.StartTaskDialog.UseVisualStyleBackColor = true;
+            this.StartTaskDialog.Click += new System.EventHandler(this.StartTaskDialog_Click);
+            // 
             // DialogsTesting
             // 
             this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
             this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
             this.ClientSize = new System.Drawing.Size(623, 237);
+            this.Controls.Add(this.StartTaskDialog);
             this.Controls.Add(this.SaveFileDialog);
             this.Controls.Add(this.OpenFileDialog);
             this.Controls.Add(this.FolderBrowserDialog);
@@ -108,6 +120,7 @@
         private System.Windows.Forms.Button FolderBrowserDialog;
         private System.Windows.Forms.Button OpenFileDialog;
         private System.Windows.Forms.Button SaveFileDialog;
+        private System.Windows.Forms.Button StartTaskDialog;
     }
 }
 

src/System.Windows.Forms/tests/AccessibilityTests/DialogsTesting.cs

@@ -42,6 +42,93 @@ namespace AccessibilityTests
             SaveFileDialog saveFileDialog = new SaveFileDialog();
             saveFileDialog.ShowDialog();
         }
+
+        private void StartTaskDialog_Click(object sender, EventArgs e)
+        {
+            ShowEventsDemoTaskDialog();
+        }
+
+        private void ShowEventsDemoTaskDialog()
+        {
+            var page1 = new TaskDialogPage()
+            {
+                Caption = Text,
+                Heading = "Event Demo",
+                Text = "Event Demo...",
+            };
+
+            page1.Created += (s, e) => Console.WriteLine("Page1 Created");
+            page1.Destroyed += (s, e) => Console.WriteLine("Page1 Destroyed");
+            page1.HelpRequest += (s, e) => Console.WriteLine("Page1 HelpRequest");
+
+            page1.Expander = new TaskDialogExpander("Expander")
+            {
+                Position = TaskDialogExpanderPosition.AfterFootnote
+            };
+
+            page1.Expander.ExpandedChanged += (s, e) => Console.WriteLine("Expander ExpandedChanged: " + page1.Expander.Expanded);
+
+            var buttonOK = TaskDialogButton.OK;
+            var buttonHelp = TaskDialogButton.Help;
+            var buttonCancelClose = new TaskDialogCommandLinkButton("C&ancel Close", allowCloseDialog: false);
+            var buttonShowInnerDialog = new TaskDialogCommandLinkButton("&Show (modeless) Inner Dialog", "(and don't cancel the Close)");
+            var buttonNavigate = new TaskDialogCommandLinkButton("&Navigate", allowCloseDialog: false);
+
+            page1.Buttons.Add(buttonOK);
+            page1.Buttons.Add(buttonHelp);
+            page1.Buttons.Add(buttonCancelClose);
+            page1.Buttons.Add(buttonShowInnerDialog);
+            page1.Buttons.Add(buttonNavigate);
+
+            buttonOK.Click += (s, e) => Console.WriteLine($"Button '{s}' Click");
+            buttonHelp.Click += (s, e) => Console.WriteLine($"Button '{s}' Click");
+
+            buttonCancelClose.Click += (s, e) =>
+            {
+                Console.WriteLine($"Button '{s}' Click");
+            };
+
+            buttonShowInnerDialog.Click += (s, e) =>
+            {
+                Console.WriteLine($"Button '{s}' Click");
+                TaskDialog.ShowDialog(new TaskDialogPage()
+                {
+                    Text = "Inner Dialog"
+                });
+                Console.WriteLine($"(returns) Button '{s}' Click");
+            };
+
+            buttonNavigate.Click += (s, e) =>
+            {
+                Console.WriteLine($"Button '{s}' Click");
+
+                // Navigate to a new page.
+                var page2 = new TaskDialogPage()
+                {
+                    Heading = "AfterNavigation.",
+                    Buttons =
+                    {
+                        TaskDialogButton.Close
+                    }
+                };
+                page2.Created += (s, e) => Console.WriteLine("Page2 Created");
+                page2.Destroyed += (s, e) => Console.WriteLine("Page2 Destroyed");
+
+                page1.Navigate(page2);
+            };
+
+            page1.Verification = new TaskDialogVerificationCheckBox("&CheckBox1");
+            page1.Verification.CheckedChanged += (s, e) => Console.WriteLine("CheckBox CheckedChanged: " + page1.Verification.Checked);
+
+            var radioButton1 = page1.RadioButtons.Add("Radi&oButton1");
+            var radioButton2 = page1.RadioButtons.Add("RadioB&utton2");
+
+            radioButton1.CheckedChanged += (s, e) => Console.WriteLine("RadioButton1 CheckedChanged: " + radioButton1.Checked);
+            radioButton2.CheckedChanged += (s, e) => Console.WriteLine("RadioButton2 CheckedChanged: " + radioButton2.Checked);
+
+            var dialogResult = TaskDialog.ShowDialog(page1);
+            Console.WriteLine("---> Dialog Result: " + dialogResult);
+        }
     }
 }