JeffreySu/WeiXinMPSDK · error · ArgumentNullException

data 不能为 null！

Error message

data 不能为 null！

What it means

Inside TenPayApiRequest.GetHttpResponseMessageAsync, after validating timeOut and building the HttpRequestMessage, the method branches on the request method; a null data (request body) is rejected before the request is sent. The exception fires when a caller requests a POST/PUT-style API call without supplying the JSON object to serialize as the body — WeChat Pay V3 endpoints require a payload for these methods, so a null body is invalid.

Solutions

1. Pass an empty object (new { }) or the actual request DTO for POST/PUT/PATCH calls
2. Set checkDataNotNull: false if the endpoint genuinely accepts an empty body
3. Check that your DTO construction/mapping does not return null

Example fix

// before
await tenPayApiRequest.PostAsync(url, null);
// after
await tenPayApiRequest.PostAsync(url, new { }); // or the required request DTO

if (data == null && checkDataNotNull) data = new { }; // or throw early with context

try { await request.PostAsync(url, data); }
catch (ArgumentNullException ex) when (ex.ParamName?.StartsWith("data") == true) { log.Error("POST 请求 body 为空", ex); throw; }

When it happens

Trigger: Calling PostAsync/PutAsync/PatchAsync with data == null (e.g. an empty request DTO not constructed, or a LINQ/serialization result that returned null) while leaving checkDataNotNull at its default true.

Common situations: Sending POST endpoints that technically accept no body but calling the method without an object; a null model from a failed mapping step.

Related errors

• tenPayV3Info 参数不能为空！
• brandApiCredentials
• fileStream
• buttonGroupBase不可以为空！
• WeixinPayInfoCollection尚未注册Partner：

AI-assisted analysis of JeffreySu/WeiXinMPSDK@be573f6f94 (2026-09-12). Data as JSON: /api/errors/f1005d01a1366870. Report an issue: GitHub.

Appendix: source

Thrown at src/Senparc.Weixin.TenPay/Senparc.Weixin.TenPayV3/HttpHandlers/TenPayApiRequest.cs:232

            if (timeOut <= 0 && timeOut != Timeout.Infinite)
            {
                throw new ArgumentOutOfRangeException(nameof(timeOut), "超时时间必须大于 0，或使用 Timeout.Infinite。 ");
            }

            using var request = new HttpRequestMessage(GetHttpMethod(requestMethod), url);

            switch (requestMethod)
            {
                case ApiRequestMethod.GET:
                case ApiRequestMethod.DELETE:
                    WeixinTrace.Log(url);
                    break;
                case ApiRequestMethod.POST:
                case ApiRequestMethod.PUT:
                case ApiRequestMethod.PATCH:
                    if (checkDataNotNull)
                    {
                        _ = data ?? throw new ArgumentNullException($"{nameof(data)} 不能为 null！");
                    }

                    string jsonString = data != null
                        ? data.ToJson(false, RequestJsonSerializerSettings)
                        : "";
                    WeixinTrace.SendApiPostDataLog(url, jsonString);
                    request.Content = new StringContent(jsonString, Encoding.UTF8, mediaType: "application/json");
                    break;
                default:
                    throw new ArgumentOutOfRangeException(nameof(requestMethod));
            }

            using var timeoutCancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
            if (timeOut != Timeout.Infinite)
            {
                timeoutCancellationTokenSource.CancelAfter(timeOut);
            }

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