I got an error on 'Exception' part and i don't know why

Question

When i run this code i got an error on the catch (exception e) part i don't know why and the compiler say's "A local variable named 'e' cannot be declared in this scope because it would give a different meaning to 'e', which is already used in a 'parent or current' scope to denote something else"

        try
        {

            //Form Query which will insert Company and will output generated id 
            myCommand.CommandText = "Insert into Comp(company_name) Output Inserted.ID VALUES (@company_name)";
            myCommand.Parameters.AddWithValue("@company_name", txtCompName);
            int companyId = Convert.ToInt32(myCommand.ExecuteScalar());

            //For the next scenario, in case you need to execute another command do it before committing the transaction

            myTrans.Commit();

            //Output Message in message box
            MessageBox.Show("Added", "Company Added with id" + companyId, MessageBoxButtons.OK, MessageBoxIcon.Information);

        }

        catch (Exception e)
        {
            try
            {
                myTrans.Rollback();
            }
            catch (SqlException ex)
            {
                if (myTrans.Connection != null)
                {
                    MessageBox.Show("An exception of type " + ex.GetType() +
                                      " was encountered while attempting to roll back the transaction.");
                }
            }

            MessageBox.Show("An exception of type " + e.GetType() +
                              "was encountered while inserting the data.");
            MessageBox.Show("Record was written to database.");

        }
        finally
        {
            myConnection.Close();
        }

hope for your reply! Thanks!

Answer 1

You have a variable named e somewhere else in the local scope and there would be no way to disambiguate between the two.

Most likely you are in an event handler with the EventArgs parameter named e and you should rename one of the e identifiers to something else.

The following examples demonstrate this issue:

1. A conflicting parameter name

   void MyEventHandler(object source, EventArgs e)
   //                                          ^^^
   {
       try
       {
           DoSomething();
       }
       catch (Exception e)
       //              ^^^
       {
           OhNo(e);
           // Which "e" is this? Is it the Exception or the EventArgs??
       }
   }
   

2. A conflicting local variable

   void MyMethod()
   {
       decimal e = 2.71828;
       //     ^^^
   
       try
       {
           DoSomething();
       }
       catch (Exception e)
       //              ^^^
       {
           OhNo(e);
           // Which "e" is this? Is it the Exception or the Decimal??
       }
   }
   

3. Anonymous function (lambda)

   void MyMethod()
   {
       decimal e = 2.71828;
       //     ^^^
   
       var sum = Enumerable.Range(1, 10)
                           .Sum(e => e * e); //Which "e" to multiply?
       //                      ^^^
   }
   

---

Note the following does not cause the same error, because you are able to disambiguate with the this keyword:

class MyClass
{
    int e;

    void MyMethod()
    {
        try
        {
            DoSomething(e); //Here it is the Int32 field
        }
        catch (Exception e)
        {
            OhNo(e); //Here it is the exception
            DoSomethingElse(this.e); //Here it is the Int32 field
        }
    }

}

Answer 2

This means earlier you have declared a variable named e, and now in the same block of code, or a block inside of it (this try/catch block) you are again declaring it. Change Exception e to Exception except and it might work.