From 51985ef88e1ede47291168330731d18a3f8085c3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=B6ren=20Nils=20Kuklau?=
 <chucker@users.noreply.github.com>
Date: Thu, 19 Apr 2018 13:19:10 +0200
Subject: [PATCH] Update TaskDialog.cs

Possible fix for #4
---
 src/TaskDialogLib/TaskDialog.cs | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/TaskDialogLib/TaskDialog.cs b/src/TaskDialogLib/TaskDialog.cs
index b6d66ca..7c0b910 100644
--- a/src/TaskDialogLib/TaskDialog.cs
+++ b/src/TaskDialogLib/TaskDialog.cs
@@ -76,6 +76,9 @@ public class TaskDialog : DependencyObject
 		Boolean sizeToContent;
 		Boolean useDefaultIcon;
 		Boolean verificationChecked;
+		
+		// This needs to be a class member so that GC doesn't free it prematurely.
+		TaskDialogCallbackProc callback;
 
 		IconHandle iconHandle;
 		IconHandle footerIconHandle;
@@ -165,7 +168,7 @@ public class TaskDialog : DependencyObject
 
 		#endregion
 
-		#region Constructors
+		#region Constructors and Destructors
 
 		/// <summary>
 		/// Initializes a new instance of the TaskDialog class.
@@ -178,6 +181,14 @@ public TaskDialog()
 			useDefaultIcon = true;
 		}
 
+		/// <summary>
+		/// Cleans up the TaskDialog class.
+		/// </summary>
+		~TaskDialog()
+		{
+			callback = null;
+		}
+
 		#endregion
 
 		#region Events
@@ -762,7 +773,7 @@ public TaskDialogResult Show()
 			NativeMethods.TASKDIALOGCONFIG taskDialogConfig = new NativeMethods.TASKDIALOGCONFIG();
 			taskDialogConfig.cbSize = (UInt32)Marshal.SizeOf(typeof(NativeMethods.TASKDIALOGCONFIG));
 			taskDialogConfig.hInstance = NativeMethods.GetModuleHandle();
-			taskDialogConfig.pfCallback = TaskDialogProc;
+			taskDialogConfig.pfCallback = callback = TaskDialogProc;
 
 			Debug.Assert(taskDialogConfig.hInstance != IntPtr.Zero);