From 21014ec80792b8ef0a9a1f611bc032b0c06d7797 Mon Sep 17 00:00:00 2001
From: maliming <malimings@gmail.com>
Date: Wed, 24 Feb 2021 16:59:20 +0800
Subject: [PATCH] Handle null value.

---
 .../Mvc/AspNetCoreApiDescriptionModelProviderOptions.cs       | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProviderOptions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProviderOptions.cs
index ba5041a067..f807efcfdf 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProviderOptions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProviderOptions.cs
@@ -63,14 +63,14 @@ namespace Volo.Abp.AspNetCore.Mvc
                 if (apiParameterDescription.ModelMetadata is DefaultModelMetadata defaultModelMetadata)
                 {
                     var jsonPropertyNameAttribute = (System.Text.Json.Serialization.JsonPropertyNameAttribute)
-                        defaultModelMetadata.Attributes.PropertyAttributes.FirstOrDefault(x => x is System.Text.Json.Serialization.JsonPropertyNameAttribute);
+                        defaultModelMetadata?.Attributes?.PropertyAttributes?.FirstOrDefault(x => x is System.Text.Json.Serialization.JsonPropertyNameAttribute);
                     if (jsonPropertyNameAttribute != null)
                     {
                         return jsonPropertyNameAttribute.Name;
                     }
 
                     var jsonPropertyAttribute = (Newtonsoft.Json.JsonPropertyAttribute)
-                        defaultModelMetadata.Attributes.PropertyAttributes.FirstOrDefault(x => x is Newtonsoft.Json.JsonPropertyAttribute);
+                        defaultModelMetadata?.Attributes?.PropertyAttributes?.FirstOrDefault(x => x is Newtonsoft.Json.JsonPropertyAttribute);
                     if (jsonPropertyAttribute != null)
                     {
                         return jsonPropertyAttribute.PropertyName;