In subservience application i want to use some app.config values for that when I am trying to use following code I get warning message "ConfigurationSettings.AppSettings is obsolete”

string mode = ConfigurationManager.AppSettings["Mode"].ToUpper();

 string mode = ConfigurationManager.AppSettings["Mode"].ToUpper();

TransactionScope Error:The transaction has aborted.

This error you may face in two conditions

 1. Time out condition.

 2.  Inside scope other command transaction failing or rollbacks.

Solution:

Timeout Exception:

You can resolve timeout condition issue increasing transaction scope timeout and

Ensure timeout of the transaction scope is longer than the command timeout.

var option = new TransactionOptions
                    {
IsolationLevel = System.Transactions.IsolationLevel.ReadCommitted,
                        Timeout = TimeSpan.FromSeconds(90)
                    };

myContext.CommandTimeout
= 60; //This is seconds

Inner command transaction failing:

Logical insert failing:

With following example in insert logic what if insert store procedure has some Logic that prevents duplicate records insertion if new records then only insert Records (if else used).
In this scenario logically insert is not failing but command.ExecuteNonQuery will return Result 0 and command rollbacks transaction.
You can avoid this by passing output parameter and set parameter value as continue update that will resolve your issue.

Inner exception:

Another scenario is that what if toy get exception inside scope for sub process , you can pass it to parent exception and process for next update that will resolve your issue.

  try
        {
            using (TransactionScope scope = new TransactionScope(TransactionScopeOption.RequiresNew))
            {
                // insert logic
                try
                {
                    using (var conn = GetConnection())
                    {
                                string query =
                  @" insert Quiery"
 
                       using (var command = new SqlCommand(query, conn))
                        var rowsAffected = Command.ExecuteNonQuery();
                        if (rowsAffected >= 1&&ContinueUpate==1)
                        {
                            Command.Transaction.Commit();
                            status = true;
                        }
                        else
                        {
                            Command.Transaction.Rollback();
                        }
                    }
                }
                catch (SqlException ex)
                {
                    // log your exception
                    throw;  // re-throw exception
                }
 
               // update logic
                try
                {
                    using (var conn = GetConnection())
                    {
                          string query = @" Delete Quiery"
                    }
                }
                catch (SqlException ex)
                {
                    // log your exception
                    throw;  // re-throw exception
                }
                scope.Complete();
            }
        }
     // this catch block will resolve your issue
        catch (TransactionAbortedException ex)
        {
            //you can log here internal exception if you want  
        }

When I am trying to remove element from generic list using foreach loop, I am facing following issue.

Error:

Collection was modified; enumeration operation may not execute.

My code:

  if (duplicateUsers != null && duplicateUsers.Count()> 1)
           {
                        
             foreach (var duplicateUserData in duplicateUsers)
             {
                UsersData.Remove(duplicateUserData); 
             }
           }

Fix:

If you are using generic list then simply use extension method ToList() with list i.e

duplicateUsers .ToList()

Your code should be:

  if (duplicateUsers != null && duplicateUsers.Count()> 1)
           {        
             foreach (var duplicateUserData in duplicateUsers.ToList())
             {
                UsersData.Remove(duplicateUserData); 
             }
           }