From a7cc9723262daebd4e44db4482b838c88d56a0a6 Mon Sep 17 00:00:00 2001
From: Alex Maitland <amaitland@users.noreply.github.com>
Date: Wed, 21 Aug 2024 18:42:31 +1000
Subject: [PATCH] WPF/OffScreen - NullReferenceException in the
 WaitForRenderIdleAsync method

- Catch and throw exception back onto the calling thread so it doesn't crash the app

Resovles #4902
---
 CefSharp.OffScreen/ChromiumWebBrowser.cs | 4 ++++
 CefSharp.Wpf/ChromiumWebBrowser.cs       | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/CefSharp.OffScreen/ChromiumWebBrowser.cs b/CefSharp.OffScreen/ChromiumWebBrowser.cs
index 7d4e02f24c..28ce08ff53 100644
--- a/CefSharp.OffScreen/ChromiumWebBrowser.cs
+++ b/CefSharp.OffScreen/ChromiumWebBrowser.cs
@@ -762,6 +762,10 @@ public async Task WaitForRenderIdleAsync(int idleTimeInMs = 500, TimeSpan? timeo
                     // the same time, the timer maybe Disposed on a different thread.
                     // https://github.com/cefsharp/CefSharp/issues/4597
                 }
+                catch(Exception ex)
+                {
+                    renderIdleTcs.TrySetException(ex);
+                }
             };
 
             idleTimer.Start();
diff --git a/CefSharp.Wpf/ChromiumWebBrowser.cs b/CefSharp.Wpf/ChromiumWebBrowser.cs
index 3af233711f..4358c0606b 100644
--- a/CefSharp.Wpf/ChromiumWebBrowser.cs
+++ b/CefSharp.Wpf/ChromiumWebBrowser.cs
@@ -2754,6 +2754,10 @@ public async Task WaitForRenderIdleAsync(int idleTimeInMs = 500, TimeSpan? timeo
                     // the same time, the timer maybe Disposed on a different thread.
                     // https://github.com/cefsharp/CefSharp/issues/4597
                 }
+                catch (Exception ex)
+                {
+                    renderIdleTcs.TrySetException(ex);
+                }
             };
 
             idleTimer.Start();