If there any alternative for parallel foreach issue

Question

If there any alternative for parallel foreach issue

Settu Ranganathan 1

1. We are using the parallel foreach for Asyn process, and it sometimes returns an unexpected value, how can I resolve this functionality issue
Or is there any alternative solution for parallel foreach

Lan Huang-MSFT 30,186 Reputation points Microsoft External Staff

2023-03-10T09:48:08.89+00:00

Hi @Settu Ranganathan,

Is your project an Asp.Net MVC project?

You can provide your code so that we can better help you to solve the problem,

more information you can refer to this thread.

Settu Ranganathan 1

Is your project an Asp.Net MVC project?---> yes, am using 
Asp.Net MVC project

You can find the below sample code

Parallel.ForEach(nodees, xObj =>             
               

                     
                    {

                        DataSet Displayedcustomfilter = new DataSet();
                    ET_Sample Sample = new ET_Sample();
                    ET_Sample1 outputSample1 = new ET_Sample1();

                    Sample.param1 = Convert.ToInt32(xObj.SelectSingleNode("param1").InnerText);
                    Sample.param1 = xObj.SelectSingleNode("param1").InnerText;
                    Sample.param1 = xObj.SelectSingleNode("param1").InnerText;
                    Sample.param1 = xObj.SelectSingleNode("param1").InnerText;

                    //Getting externalDBconfig info from externalApplications table
                    externalDBConnection = ExternalApplicationsAPI.serverdetails(Convert.ToInt32(Sample.ExternalDBConfigID));
                    Sample.ExternalDBServerName = externalDBConnection.Config1;
                    Sample.ExternalDBDatabaseName = externalDBConnection.Config2;
                    Sample.ExternalDBUserID = externalDBConnection.Config3;
                    Sample.ExternalDBPassword = externalDBConnection.Config4;
                    Sample.ExternalDBSPName = externalDBConnection.Config5;
                    Sample.IsDataSetFormat = Convert.ToInt32(externalDBConnection.Config6.ToString() == "" ? "0" : externalDBConnection.Config6.ToString());
                    Sample.DynamicFilterSP = externalDBConnection.Config9;                   
                    IscustomFilterEnabled = Convert.ToInt32(externalDBConnection.Config9.ToString() != "" ? "1" : "0");
                    Paging = Convert.ToInt32(externalDBConnection.Config7.ToString() == "1" ? externalDBConnection.Config7.ToString() : "0");
                    FinancialPaging = Convert.ToInt32(externalDBConnection.Config10.ToString() == "1" ? externalDBConnection.Config10.ToString() : "0");
                    //Making Connection String
                    Sample.ExternalDBConnectionString = Sample.GenerateConnectionString();
                    //Calling ExternalDB request call to get medical summary from outside DB
                    using (DataSet ds = CustomerPatientAffiliationAPI.GetPatientSample(param1, param2, param3, param4))
                    {

                        if (ds.Tables.Count > 0)
                        {
                            if (Sample.IsDataSetFormat == 1)
                            {

                                foreach (DataTable table in ds.Tables)
                                {
                                    table.TableName = table.Rows[0]["headerid"].ToString();
                                    table.Columns.Remove(table.Columns["headername"].ColumnName);
                                }
                                var customJsonObj = new { Patient = ds };
                                outputSample.JsonData = JsonConvert.SerializeObject(customJsonObj);

                            }
                            else
                            {
                                outputSample.JsonData = ds.Tables[0].Rows[0]["JsonData"].ToString();
                            }
                            outputSample.param1 = Guid.Parse(param1);
                            outputSample.param2 = Sample.param2;
                            outputSample.param3 = Sample.param3;
                            objSample.Add(outputSample);
                        }
                    }

                    if (IscustomFilterEnabled == 1)
                    {
                        using (DataSet CustomFilter = CustomerPatientAffiliationAPI.GetPatientSampleCustomComboFilters(param1, param2, param3, param4))
                        {
                            if (CustomFilter.Tables.Count > 0)
                            {
                                foreach (DataTable table in CustomFilter.Tables)
                                {
                                    if (table.Rows.Count > 0)
                                    {
                                        table.TableName = table.Rows[0]["ComboName"].ToString();
                                        if (Displayedcustomfilter.Tables.Count < 7)
                                        {
                                            DataTable dtCopy;
                                            dtCopy = table.Copy();
                                            Displayedcustomfilter.Tables.Add(dtCopy);
                                        }
                                    }
                                }
                                var customFilterJsonObj = new { Patient = Displayedcustomfilter };
                                outputSample.DynamicFilterJsonData = JsonConvert.SerializeObject(customFilterJsonObj);
                            }
                            else
                            {
                                outputSample.DynamicFilterJsonData = "";
                            }
                        }
                    }
                });

Lan Huang-MSFT 30,186 Reputation points Microsoft External Staff

2023-03-15T08:41:25.1433333+00:00

Hi @Settu Ranganathan,

Parallel.ForEach doesn't work with async. It just takes an Action as input and executes it for each item. In the case of asynchronous delegates, it executes them in a fire-and-forget fashion.

You can try to create tasks with the help of Select and use Task.WhenAll to execute them concurrently.

You can check this post for details.
Settu Ranganathan 1 Reputation point

2023-03-15T10:58:02.55+00:00

Hi @Lan Huang-MSFT

what I need is, we are facing an issue with Parallel for each.

Example scenario:

I have more than 2 list values. I used these 2 values in Parallel foreach.

Sometimes sending the correct values to SP call, sometimes sending the wrong values to SP call. I want to know how to rectify this issue or I need the best alternative option for this
Lan Huang-MSFT 30,186 Reputation points Microsoft External Staff

2023-03-16T09:10:04.1233333+00:00

Hi @Settu Ranganathan,

I don't know if there is a problem with what I described. You said at the beginning that the Asyn process uses parallel foreach, but Parallel.Foreach does not support async/await.

You can try to create tasks with the help of Select and use Task.WhenAll to execute them concurrently.

You can check this post for details.

https://stackoverflow.com/questions/60336195/parallel-foreach-not-adding-items-as-expected-in-concurrentbag-in-c-sharp/60336329#60336329

2 answers

Your answer

Lan Huang-MSFT 30,186 Reputation points Microsoft External Staff

2023-03-10T09:48:08.89+00:00

Hi @Settu Ranganathan,

Is your project an Asp.Net MVC project?

You can provide your code so that we can better help you to solve the problem,

more information you can refer to this thread.
Lan Huang-MSFT 30,186 Reputation points Microsoft External Staff

2023-03-15T08:41:25.1433333+00:00

Hi @Settu Ranganathan,

Parallel.ForEach doesn't work with async. It just takes an Action as input and executes it for each item. In the case of asynchronous delegates, it executes them in a fire-and-forget fashion.

You can try to create tasks with the help of Select and use Task.WhenAll to execute them concurrently.

You can check this post for details.
Settu Ranganathan 1 Reputation point

2023-03-15T10:58:02.55+00:00

Hi @Lan Huang-MSFT

what I need is, we are facing an issue with Parallel for each.

Example scenario:

I have more than 2 list values. I used these 2 values in Parallel foreach.

Sometimes sending the correct values to SP call, sometimes sending the wrong values to SP call. I want to know how to rectify this issue or I need the best alternative option for this
Lan Huang-MSFT 30,186 Reputation points Microsoft External Staff

2023-03-16T09:10:04.1233333+00:00

Hi @Settu Ranganathan,

I don't know if there is a problem with what I described. You said at the beginning that the Asyn process uses parallel foreach, but Parallel.Foreach does not support async/await.

You can try to create tasks with the help of Select and use Task.WhenAll to execute them concurrently.

You can check this post for details.

https://stackoverflow.com/questions/60336195/parallel-foreach-not-adding-items-as-expected-in-concurrentbag-in-c-sharp/60336329#60336329

Answer 1

Viorel 122.5K

If you are using the .NET 6 or higher, then consider await Parallel.ForEachAsync(...).

Otherwise, show details to reproduce the problem.

Answer 2

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This answer has been deleted due to a violation of our Code of Conduct. The answer was manually reported or identified through automated detection before action was taken. Please refer to our Code of Conduct for more information.

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If there any alternative for parallel foreach issue

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