diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinAgentExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinAgentExtensions.cs
index ba00c7c1..d402bba7 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinAgentExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinAgentExtensions.cs
@@ -26,7 +26,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
@@ -72,7 +72,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
@@ -96,7 +96,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
@@ -121,7 +121,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
@@ -145,7 +145,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
@@ -169,7 +169,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinCorpExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinCorpExtensions.cs
index 8b823ff9..d5fb4b6a 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinCorpExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinCorpExtensions.cs
@@ -28,7 +28,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
                 .CreateRequest(request, HttpMethod.Get, "cgi-bin", "corp", "get_join_qrcode")
                 .SetQueryParam("access_token", request.AccessToken);
 
-            if (request.SizeType.HasValue)
+            if (request.SizeType != null)
                 flurlReq.SetQueryParam("size_type", request.SizeType.Value);
 
             return await client.SendRequestWithJsonAsync<Models.CgibinCorpGetJoinQrcodeResponse>(flurlReq, cancellationToken: cancellationToken);
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinCorpGroupExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinCorpGroupExtensions.cs
index a1f9c877..13ba228e 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinCorpGroupExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinCorpGroupExtensions.cs
@@ -25,7 +25,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.ParentAgentId.HasValue)
+            if (request.ParentAgentId == null)
                 request.ParentAgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinDepartmentExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinDepartmentExtensions.cs
index e1a82b17..b99d1197 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinDepartmentExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinDepartmentExtensions.cs
@@ -97,7 +97,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
                 .CreateRequest(request, HttpMethod.Get, "cgi-bin", "department", "list")
                 .SetQueryParam("access_token", request.AccessToken);
 
-            if (request.ParentDepartmentId.HasValue)
+            if (request.ParentDepartmentId != null)
                 flurlReq.SetQueryParam("id", request.ParentDepartmentId.Value);
 
             return await client.SendRequestWithJsonAsync<Models.CgibinDepartmentListResponse>(flurlReq, cancellationToken: cancellationToken);
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs
index e2b55189..499425a8 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinExternalContactExtensions.cs
@@ -1008,7 +1008,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinLinkedCorpExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinLinkedCorpExtensions.cs
index 1bb0e689..bdd2223f 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinLinkedCorpExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinLinkedCorpExtensions.cs
@@ -125,7 +125,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMediaExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMediaExtensions.cs
index eab74b23..55470002 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMediaExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMediaExtensions.cs
@@ -30,7 +30,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             const string TYPE_VOICE = "voice";
             const string TYPE_VIDEO = "video";
 
-            if (string.IsNullOrEmpty(request.FileName))
+            if (request.FileName == null)
             {
                 string ext = "";
                 if (TYPE_IMAGE.Equals(request.Type))
@@ -43,7 +43,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
                 request.FileName = Guid.NewGuid().ToString("N").ToLower() + ext;
             }
 
-            if (string.IsNullOrEmpty(request.FileContentType))
+            if (request.FileContentType == null)
             {
                 if (TYPE_IMAGE.Equals(request.Type))
                     request.FileContentType = Utilities.FileNameToContentTypeMapper.GetContentTypeForImage(request.FileName!) ?? "image/png";
@@ -86,10 +86,10 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (string.IsNullOrEmpty(request.FileName))
+            if (request.FileName == null)
                 request.FileName = Guid.NewGuid().ToString("N").ToLower() + ".png";
 
-            if (string.IsNullOrEmpty(request.FileContentType))
+            if (request.FileContentType == null)
                 request.FileContentType = Utilities.FileNameToContentTypeMapper.GetContentTypeForImage(request.FileName!) ?? "image/png";
 
             IFlurlRequest flurlReq = client
@@ -125,7 +125,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             const string TYPE_VIDEO = "video";
             const string TYPE_FILE = "file";
 
-            if (string.IsNullOrEmpty(request.FileName))
+            if (request.FileName == null)
             {
                 string ext = "";
                 if (TYPE_IMAGE.Equals(request.Type))
@@ -138,7 +138,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
                 request.FileName = Guid.NewGuid().ToString("N").ToLower() + ext;
             }
 
-            if (string.IsNullOrEmpty(request.FileContentType))
+            if (request.FileContentType == null)
             {
                 if (TYPE_IMAGE.Equals(request.Type))
                     request.FileContentType = Utilities.FileNameToContentTypeMapper.GetContentTypeForImage(request.FileName!) ?? "image/png";
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMenuExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMenuExtensions.cs
index 1bb04664..feefc5e6 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMenuExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMenuExtensions.cs
@@ -24,7 +24,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
@@ -48,7 +48,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
@@ -72,7 +72,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMessageExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMessageExtensions.cs
index 5d7a488d..c7f17650 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMessageExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinMessageExtensions.cs
@@ -26,7 +26,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
@@ -50,7 +50,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
@@ -74,7 +74,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (!request.AgentId.HasValue)
+            if (request.AgentId == null)
                 request.AgentId = client.Credentials.AgentId;
 
             IFlurlRequest flurlReq = client
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinSchoolExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinSchoolExtensions.cs
index 1b00a622..4db95d8a 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinSchoolExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinSchoolExtensions.cs
@@ -135,7 +135,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
                 .SetQueryParam("access_token", request.AccessToken)
                 .SetQueryParam("department_id", request.DeparmentId);
 
-            if (request.RequireFetchChild.HasValue)
+            if (request.RequireFetchChild != null)
                 flurlReq.SetQueryParam("fetch_child", request.RequireFetchChild.Value ? 1 : 0);
 
             return await client.SendRequestWithJsonAsync<Models.CgibinSchoolUserListResponse>(flurlReq, cancellationToken: cancellationToken);
@@ -566,7 +566,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
                 .CreateRequest(request, HttpMethod.Get, "cgi-bin", "school", "department", "list")
                 .SetQueryParam("access_token", request.AccessToken);
 
-            if (request.ParentDepartmentId.HasValue)
+            if (request.ParentDepartmentId != null)
                 flurlReq.SetQueryParam("id", request.ParentDepartmentId);
 
             return await client.SendRequestWithJsonAsync<Models.CgibinSchoolDepartmentListResponse>(flurlReq, cancellationToken: cancellationToken);
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinServiceExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinServiceExtensions.cs
index 6011ff03..c3312a51 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinServiceExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinServiceExtensions.cs
@@ -46,10 +46,10 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             if (client is null) throw new ArgumentNullException(nameof(client));
             if (request is null) throw new ArgumentNullException(nameof(request));
 
-            if (string.IsNullOrEmpty(request.SuiteId))
+            if (request.SuiteId == null)
                 request.SuiteId = client.Credentials.SuiteId;
 
-            if (string.IsNullOrEmpty(request.SuiteSecret))
+            if (request.SuiteSecret == null)
                 request.SuiteSecret = client.Credentials.SuiteSecret;
 
             IFlurlRequest flurlReq = client
@@ -246,7 +246,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
             const string TYPE_VOICE = "voice";
             const string TYPE_VIDEO = "video";
 
-            if (string.IsNullOrEmpty(request.FileName))
+            if (request.FileName == null)
             {
                 string ext = "";
                 if (TYPE_IMAGE.Equals(request.Type))
@@ -259,7 +259,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
                 request.FileName = Guid.NewGuid().ToString("N").ToLower() + ext;
             }
 
-            if (string.IsNullOrEmpty(request.FileContentType))
+            if (request.FileContentType == null)
             {
                 if (TYPE_IMAGE.Equals(request.Type))
                     request.FileContentType = Utilities.FileNameToContentTypeMapper.GetContentTypeForImage(request.FileName!) ?? "image/png";
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinUserExtensions.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinUserExtensions.cs
index 48a330ea..d9eeb593 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinUserExtensions.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/Extensions/WechatWorkClientExecuteCgibinUserExtensions.cs
@@ -143,7 +143,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
                 .SetQueryParam("access_token", request.AccessToken)
                 .SetQueryParam("department_id", request.DepartmentId);
 
-            if (request.RequireFetchChild.HasValue)
+            if (request.RequireFetchChild != null)
                 flurlReq.SetQueryParam("fetch_child", request.RequireFetchChild.Value ? 1 : 0);
 
             return await client.SendRequestWithJsonAsync<Models.CgibinUserSimpleListResponse>(flurlReq, cancellationToken: cancellationToken);
@@ -169,7 +169,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
                 .SetQueryParam("access_token", request.AccessToken)
                 .SetQueryParam("department_id", request.DepartmentId);
 
-            if (request.RequireFetchChild.HasValue)
+            if (request.RequireFetchChild != null)
                 flurlReq.SetQueryParam("fetch_child", request.RequireFetchChild.Value ? 1 : 0);
 
             return await client.SendRequestWithJsonAsync<Models.CgibinUserListResponse>(flurlReq, cancellationToken: cancellationToken);
@@ -324,10 +324,10 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
                 .CreateRequest(request, HttpMethod.Get, "cgi-bin", "user", "list_member_auth")
                 .SetQueryParam("access_token", request.AccessToken);
 
-            if (!string.IsNullOrEmpty(request.NextCursor))
+            if (request.NextCursor != null)
                 flurlReq.SetQueryParam("cursor", request.NextCursor);
 
-            if (request.Limit.HasValue)
+            if (request.Limit != null)
                 flurlReq.SetQueryParam("limit", request.Limit);
 
             return await client.SendRequestWithJsonAsync<Models.CgibinUserListMemberAuthResponse>(flurlReq, cancellationToken: cancellationToken);
diff --git a/src/SKIT.FlurlHttpClient.Wechat.Work/WechatWorkClient.cs b/src/SKIT.FlurlHttpClient.Wechat.Work/WechatWorkClient.cs
index 46f90b56..c165f02b 100644
--- a/src/SKIT.FlurlHttpClient.Wechat.Work/WechatWorkClient.cs
+++ b/src/SKIT.FlurlHttpClient.Wechat.Work/WechatWorkClient.cs
@@ -59,7 +59,7 @@ namespace SKIT.FlurlHttpClient.Wechat.Work
         {
             IFlurlRequest flurlRequest = FlurlClient.Request(urlSegments).WithVerb(method);
 
-            if (request.Timeout.HasValue)
+            if (request.Timeout != null)
             {
                 flurlRequest.WithTimeout(TimeSpan.FromMilliseconds(request.Timeout.Value));
             }