数据为空。不能对 Null 值调用此方法或属性。当 dbcontext.codeddata

Question

我正在从 .NET Core 调用存储过程：

[Authorize(Roles = "1,2,3")]
[HttpPost("SaveDocumentAndParties")]
public async Task<IActionResult> saveDocumentAndParties([FromBody] SaveDocumentParties sd)
{
    string jsondata = string.Empty;

    await _lock.WaitAsync().ConfigureAwait(false);

    using (var dbContext = _dbContextFactory.CreateDbContext())
    {
        dbContext.Database.GetDbConnection().ConnectionString = sd.ConnectionString;

        try
        {
            if (dbContext.Database.GetDbConnection().State == ConnectionState.Open)
            {
                dbContext.Database.GetDbConnection().Close();
            }

            // Open the connection
              
            var Title = Regex.Replace(sd.Title, @"\s+", "");
            var actionParam = new SqlParameter("@Action", "Save");

            var partiesHistoryJsonParam = new SqlParameter("@partiesHistoryJson", sd.arrayParties);
            var exportExtraHistoryJsonParam = new SqlParameter("@exportExtraHistoryJson", sd.customField);
            var fieldSettingsJsonParam = new SqlParameter("@FieldSettingsJson", sd.FieldSettings);
            var codingSessionDetailsParam = new SqlParameter("@CodingSessionDetails", sd.CodingSessionDetails == "undefined" || String.IsNullOrEmpty(sd.CodingSessionDetails) == true ? null : sd.CodingSessionDetails);
            var documentIdParam = new SqlParameter("@DocumentID", sd.Document_ID);
            var projectIdParam = new SqlParameter("@ProjectId", sd.ProjectId);
            var documentDateParam = new SqlParameter("@DocumentDate", sd.Document_Date);
            var documentTypeParam = new SqlParameter("@DocumentType", sd.Document_Type);
            var enteredByIdParam = new SqlParameter("@EnteredById", sd.EnterBy);
            var estimatedParam = new SqlParameter("@Estimated", sd.Estimated);
            var titleParam = new SqlParameter("@Title", sd.Title);
            var codingQATimeParam = new SqlParameter("@CodingQATime", sd.CodingQATime);
            var isCorrectedParam = new SqlParameter("@IsCorrected", sd.IsCorrected);
            var userTaskParam = new SqlParameter("@UserTask", sd.UserTask);
            var isHistoryDocumentParam = new SqlParameter("@isHistoryDocument", sd.isHistoryDocument);
            var returnJSONResultParam = new SqlParameter("@ReturnJSONResult", null);
            // var returnJSONResultParam = new SqlParameter("@ReturnJSONResult", System.Data.SqlDbType.NVarChar, -1);
            // returnJSONResultParam.Direction = System.Data.ParameterDirection.Output;

            var sql1 = "[dbo].[sp_SaveCodedDatas] {0},{1},{2},{3},{4},{5},{6},{7},{8},{9}";

            // Execute the stored procedure

            // Initialize the parameters
            documentIdParam = documentIdParam ?? throw new ArgumentNullException(nameof(documentIdParam));
            projectIdParam = projectIdParam ?? throw new ArgumentNullException(nameof(projectIdParam));
            documentDateParam = documentDateParam ?? throw new ArgumentNullException(nameof(documentDateParam));
            documentTypeParam = documentTypeParam ?? throw new ArgumentNullException(nameof(documentTypeParam));
            enteredByIdParam = enteredByIdParam ?? throw new ArgumentNullException(nameof(enteredByIdParam));
            estimatedParam = estimatedParam ?? throw new ArgumentNullException(nameof(estimatedParam));
            titleParam = titleParam ?? throw new ArgumentNullException(nameof(titleParam));
            codingQATimeParam = codingQATimeParam ?? throw new ArgumentNullException(nameof(codingQATimeParam));
            isCorrectedParam = isCorrectedParam ?? throw new ArgumentNullException(nameof(isCorrectedParam));
            userTaskParam = userTaskParam ?? throw new ArgumentNullException(nameof(userTaskParam));

            var result = dbContext.Set<CodedData>().FromSqlRaw(sql1,
                    documentIdParam.Value,
                    projectIdParam.Value,
                    documentDateParam.Value,
                    documentTypeParam.Value,
                    enteredByIdParam.Value,
                    estimatedParam.Value,
                    titleParam.Value,
                    codingQATimeParam.Value,
                    isCorrectedParam.Value,
                    userTaskParam.Value).ToList();

            var sql = "[dbo].[sp_SaveDcumentAndParties] {0},{1},{2},{3},{4},{5},{6},{7},{8},{9},{10},{11},{12},{13},{14},{15},{16}";

            var jsonString = dbContext.JsonResponseResult.FromSqlRaw(sql,
                    actionParam.Value, partiesHistoryJsonParam.Value,
                    exportExtraHistoryJsonParam.Value,
                    fieldSettingsJsonParam.Value,
                    codingSessionDetailsParam.Value,
                    documentIdParam.Value,
                    projectIdParam.Value,
                    documentDateParam.Value,
                    documentTypeParam.Value,
                    enteredByIdParam.Value,
                    estimatedParam.Value,
                    titleParam.Value,
                    codingQATimeParam.Value,
                    isCorrectedParam.Value,
                    userTaskParam.Value,
                    isHistoryDocumentParam.Value,
                    returnJSONResultParam.Value).AsEnumerable().Select(x => x.JsonResponse).FirstOrDefault();

            // Retrieve the output parameter value
            // jsondata = returnJSONResultParam.Value.ToString();

            // Deserialize the JSON string into a JObject dynamically
            JObject jsonObject = JObject.Parse(jsonString);

            // Create a dictionary to represent the JSON object
            var jsonProperties = new Dictionary<string, object>();

            // Loop through each property in the JObject
            foreach (var property in jsonObject.Properties())
            {
                // Get the name and value of each property
                jsonProperties[property.Name] = property.Value.ToString();
            }

            jsondata = JsonConvert.SerializeObject(jsonObject);

            // Explicit refresh
            await dbContext.SaveChangesAsync();
            // await dbContext.CodedDatas.LoadAsync();
            // await dbContext.Entry(dbContext.CodedDatas).ReloadAsync();

            obj.Information("transaction completed - " + sd.Document_ID);
        }
        catch (SqlException ex) when (IsTransientFailure(ex))
        {
            obj.Information("SaveDocumentAndParties Transient Failure : " + ex.ToString() + ". " + sd.Document_ID);
            jsondata = Newtonsoft.Json.JsonConvert.SerializeObject(
                         new { Response = "Transient Failure", Statuscode = StatusCodes.Status500InternalServerError });
        }
        catch (Exception ex)
        {
            if (ex.Message == "Sequence contains more than one element")
            {
                obj.Information("SaveDocumentAndParties : " + ex.ToString() + ". " + sd.Document_ID);
                jsondata = Newtonsoft.Json.JsonConvert.SerializeObject(
                             new { Response = "Document Saving fail", Statuscode = StatusCodes.Status500InternalServerError });
            }
            else
            {
                var sqlException = ex.InnerException?.InnerException as SqlException;

                if (sqlException != null)
                    obj.Information("1205 - " + sqlException.Number);

                obj.Information("SaveDocumentAndParties : Main Catch Block. " + sd.Document_ID);
                obj.Information("SaveDocumentAndParties : " + ex.ToString() + ". " + sd.Document_ID);

                jsondata = Newtonsoft.Json.JsonConvert.SerializeObject(
                         new { Response = ex.Message, Statuscode = StatusCodes.Status500InternalServerError });
            }
        }
        finally
        {
            _lock.Release();
        }
    }

    return Ok(jsondata);
}

在

[dbo].[sp_SaveCodedDatas]

存储过程中，我尝试将数据插入到

Codedatas

表中，并且它已成功保存记录。

ALTER PROCEDURE [dbo].[sp_SaveCodedDatas]
    (@DocumentID VARCHAR(50) = NULL,
     @ProjectId VARCHAR(50) = NULL,
     @DocumentDate NVARCHAR(255) = NULL,
     @DocumentType NVARCHAR(255) = NULL,
     @EnteredById INT = NULL,
     @Estimated NVARCHAR(255) = NULL,
     @Title NVARCHAR(4000) = NULL,
     @CodingQATime INT = NULL,
     @IsCorrected INT = NULL,
     @UserTask VARCHAR(10) = NULL)
AS
BEGIN
    BEGIN TRY
    BEGIN TRANSACTION;

    DECLARE @TempCodedDatas AS TABLE (
       [Document_ID] NVARCHAR(255), [Image_File_Name] NVARCHAR(500), [page_label] NVARCHAR(255), [page_num] INT, [num_pages] INT,
       [Coded] INT, [Revision] INT, [DocType] NVARCHAR(255), [EnteredBy] INT, [HostDocId] NVARCHAR(255),
       [ExportDate] DATETIME, [ImportDate] DATETIME, [Percentage] INT, [SetId] INT, [DateCreated] DATETIME, 
       LastModified DATETIME, Host_Reference NVARCHAR(255),[Document_Date] DATETIME, [Estimated] NVARCHAR(255),
       [Document_Type] NVARCHAR(255),Title NVARCHAR(4000), Document_DateValue DATETIME,
       [CodingDate] DATETIME, [CodingTime] INT,[QADate] DATETIME, [QATime] INT, [IsCorrected] INT
    );

     IF @UserTask = 'Coder'
        BEGIN

            INSERT inTO @TempCodedDatas ([Document_ID], [Image_File_Name], [page_label], [page_num], [num_pages], [Coded], [Revision], [DocType], [EnteredBy], [HostDocId],
            [ExportDate], [ImportDate], [Percentage], [SetId], [DateCreated], [LastModified], [Host_Reference], [Document_Date], [Estimated], [Document_Type],
            [Title], [Document_DateValue], [CodingDate], [CodingTime], [IsCorrected])
            SELECT IPS.[Document_ID],IPS.[Image_File_Name],IPS.[page_label],IPS.[page_num],IPS.[num_pages],1 AS [Coded], 
            (CASE WHEN @UserTask='Coder' THEN 0 ELSE 1 END) AS [Revision],@DocumentType AS [DocType],@EnteredById AS [EnteredBy], 
            IPS.[HostDocId],IPS.[ExportDate],IPS.[ImportDate],IPS.[Percentage],IPS.[SetId],IPS.[DateCreated],GETDATE() AS [LastModified], 
            ICD.[Host_Reference], 
            CASE 
                WHEN ISNULL(@DocumentDate, '') = '' THEN NULL 
                ELSE CONVERT(DATETIME, @DocumentDate) 
            END AS [DocDate], 
            @Estimated AS [Estimated], 
            @DocumentType AS [Document_Type], 
            CASE 
                WHEN LEN(@Title) > 0 THEN @Title 
                ELSE 'Untitled' 
            END AS [Title], 
            CASE 
                WHEN ISNULL(ICD.Document_DateValue, '') = '' THEN NULL 
                ELSE CONVERT(DATETIME, ICD.Document_DateValue) 
            END AS [Document_DateValue], 
            GETDATE() AS [CodingDate], 
            @CodingQATime AS [CodingTime], 
            @IsCorrected AS [IsCorrected]
            FROM
                ImportPages IPS with(nolock)
            INNER JOIN 
                ImportCodedDatas ICD with(nolock) ON ICD.Document_ID = IPS.Document_ID
            WHERE 
                IPS.Document_ID = @DocumentID

            INSERT INTO CodedDatas ([Document_ID], [Image_File_Name], [page_label], [page_num], [num_pages], [Coded], [Revision], [DocType], [EnteredBy], [HostDocId],
            [ExportDate], [ImportDate], [Percentage], [SetId], [DateCreated], [LastModified], [Host_Reference], [Document_Date], [Estimated], [Document_Type],
            [Title], [Document_DateValue], [CodingDate], [CodingTime], [IsCorrected])
            SELECT [Document_ID], [Image_File_Name], [page_label], [page_num], [num_pages],[Coded], [Revision], [DocType], [EnteredBy], [HostDocId],
            [ExportDate], [ImportDate], [Percentage], [SetId], [DateCreated], LastModified, Host_Reference,
            [Document_Date], [Estimated], [DocType],Title, Document_DateValue,[CodingDate], [CodingTime], [IsCorrected]
            FROM @TempCodedDatas

            PRINT 'Coded Data Saved. '+ @DocumentID
        END
        ELSE
        BEGIN

            INSERT INTO CodedDatas ([Document_ID], [Image_File_Name], [page_label], [page_num], [num_pages], [Coded], [Revision], [DocType], [EnteredBy], [HostDocId],
            [ExportDate], [ImportDate], [Percentage], [SetId], [DateCreated], [LastModified], [Host_Reference], [Document_Date], [Estimated], [Document_Type],
            [Title], [Document_DateValue], [QADate], [QATime], [IsCorrected])
            SELECT [Document_ID], [Image_File_Name], [page_label], [page_num], [num_pages],[Coded], [Revision], [DocType], [EnteredBy], [HostDocId],
            [ExportDate], [ImportDate], [Percentage], [SetId], [DateCreated], [LastModified], Host_Reference,
            [Document_Date], [Estimated], [DocType],Title, Document_DateValue, [QADate],[QATime], [IsCorrected]
            FROM @TempCodedDatas

            PRINT 'Review Data Saved. '+ @DocumentID
        END;

        Select [Id]
  ,[Document_ID]
  ,[Image_File_Name]
  ,[page_label]
  ,[page_num]
  ,[num_pages]
  ,[Coded]
  ,[Revision]
  ,[DocType]
  ,[EnteredBy]
  ,[HostDocId]
  ,[ExportDate]
  ,[ImportDate]
  ,[Percentage]
  ,[SetId]
  ,[DateCreated]
  ,[LastModified]
  ,[main_id]
  ,[End_Page]
  ,[No_Pages]
  ,[Host_Reference]
  ,[Document_Date]
  ,[Estimated]
  ,[Document_Type]
  ,[Title]
  ,[Document_DateValue]
  ,[CodingDate]
  ,[QADate]
  ,[CodingTime]
  ,[QATime]
  ,[CodingStatus]
  ,[QAStatus]
  ,[IsCorrected]
  ,[IsBackendQA] from CodedDatas

      COMMIT TRANSACTION; -- Inner transaction commit


      END TRY
      BEGIN CATCH
      IF @@TRANCOUNT > 0
        ROLLBACK TRANSACTION; -- Inner transaction rollback
    
      -- Handle the inner catch block
      END CATCH;
END

执行存储过程后，尝试从

CodedData

表中获取记录时，出现异常并且数据为空。不能对 Null 值调用此方法或属性。在我针对其他表的另一个过程中，数据也被保存，但其他表没有问题。为什么编码数据表会出现问题？

public class CodedData
{
    [Key]
    public int Id { get; set; }
    [ConcurrencyCheck]
    public string Document_ID { get; set; }
    public string Image_File_Name { get; set; }
    public string page_label { get; set; }
    public int page_num { get; set; }
    public int num_pages { get; set; }
    [ConcurrencyCheck]
    public int Coded { get; set; }
    [ConcurrencyCheck]
    public int Revision { get; set; }
    public string DocType { get; set; }
    [ConcurrencyCheck]
    public int? EnteredBy { get; set; }
    public string HostDocId { get; set; }       
    public DateTime? ExportDate { get; set; }
    public DateTime? ImportDate { get; set; }
    public int Percentage { get; set; }
    public int SetId { get; set; }
    public DateTime? DateCreated { get; set; }
    public DateTime? LastModified { get; set; }
    public string main_id { get; set; }
    public string End_Page { get; set; }
    public int No_Pages { get; set; }
    public string Host_Reference { get; set; }
    public DateTime? Document_Date { get; set; }
    public string Estimated { get; set; }
    public string Document_Type { get; set; }
    public string Title { get; set; }
    public DateTime? Document_DateValue { get; set; }
    public DateTime? CodingDate { get; set; }
    public DateTime? QADate { get; set; }
    public int CodingTime { get; set; }
    public int QATime { get; set; }
    public int IsCorrected { get; set; }
    public string CodingStatus { get; set; }
    public string QAStatus { get; set; }

    public bool? IsBackendQA { get; set; }
}

但是当我截断

codedatas

表时，

dbcontext.codeddatas

就可以工作了。

Answer 1

请注意，例如，

titleParam = titleParam ?? throw new ...

只会测试

SqlParameter

对象是否为空。但它永远不会为空，因为你用

var titleParam = new SqlParameter("@Title", sd.Title);

分配它。这不会测试参数value是否为空。

而是直接测试这些值。例如：

var titleParam = new SqlParameter(
    "@Title",
    sd.Title ?? throw new ArgumentNullException(nameof(sd.Title))
);