Error using public override string ToString

Question

Error using public override string ToString

Raymond Gilbers 176

I need to use Public override ToString() two times, how can I do that?

 public override string ToString()  
        {  
            return MachineName ;  //Needed for showing the string into the combobox  
        }  
          
        public override string ToString()  
        {  
            return SerialNumber;  
        }

This obviously doesn't work

Jack J Jun 25,306 Reputation points

2022-07-11T06:43:22.383+00:00

@Raymond Gilbers , is any update?
Raymond Gilbers 176 Reputation points

2022-07-11T13:35:57.077+00:00

I haven't been able to dive in this issue fully yet. Im working offshore with limited internet acces and worse limited spare time. My apologies I did not respond about this. I wanted to try to use the solution that @Karen Payne MVP suggested. But I need to sit for it. By the end of this week I'm back on land and have some more spare time.

Thanks for all the help here on the forum
Karen Payne MVP 35,606 Reputation points Volunteer Moderator

2022-07-11T14:38:48.087+00:00

I created a full working code sample on GitHub found here.
Raymond Gilbers 176 Reputation points

2022-07-11T17:38:32.783+00:00

I thought I would clone your solution but this doesn't work I get a Fatal Error and tells me it can't find the file(s).

I'm sure I logged in to github I just created an account with the same email as I use Visual Studio and also added the info in Visual Studio at my account settings.

Answer accepted by question author

2 additional answers

Your answer

Jack J Jun 25,306 Reputation points

2022-07-11T06:43:22.383+00:00

@Raymond Gilbers , is any update?
Raymond Gilbers 176 Reputation points

2022-07-11T13:35:57.077+00:00

I haven't been able to dive in this issue fully yet. Im working offshore with limited internet acces and worse limited spare time. My apologies I did not respond about this. I wanted to try to use the solution that @Karen Payne MVP suggested. But I need to sit for it. By the end of this week I'm back on land and have some more spare time.

Thanks for all the help here on the forum
Karen Payne MVP 35,606 Reputation points Volunteer Moderator

2022-07-11T14:38:48.087+00:00

I created a full working code sample on GitHub found here.
Raymond Gilbers 176 Reputation points

2022-07-11T17:38:32.783+00:00

I thought I would clone your solution but this doesn't work I get a Fatal Error and tells me it can't find the file(s).

I'm sure I logged in to github I just created an account with the same email as I use Visual Studio and also added the info in Visual Studio at my account settings.

Answer 1

Karen Payne MVP 35,606 Volunteer Moderator

You can not have ToString more than once in a class.

See the definition

  [ClassInterface(ClassInterfaceType.AutoDual)]  
  [ComVisible(true)]  
  [__DynamicallyInvokable]  
  [Serializable]  
  public class Object  
  {  
    /// <summary>Initializes a new instance of the <see cref="T:System.Object" /> class.</summary>  
    [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]  
    [NonVersionable]  
    [__DynamicallyInvokable]  
    public Object()  
    {  
    }  
  
    /// <summary>Returns a string that represents the current object.</summary>  
    /// <returns>A string that represents the current object.</returns>  
    [__DynamicallyInvokable]  
    public virtual string ToString() => this.GetType().ToString();

Raymond Gilbers 176 Reputation points

2022-07-02T13:23:05.747+00:00

Thanks again for a clear answer! So this means that I would have to create another Class and so I could use Binding with another Combobox as we have done in a previous thread?
Viorel 126.9K Reputation points

2022-07-02T13:55:03.757+00:00

Maybe you can write myComboBox.DisplayMember = "MachineName" if MachineName is a public property. For the second combobox, use SerialNumber.

Karen Payne MVP 35,606 Volunteer Moderator

You could use an abstract class for a base than for one ComboBox go with the base ToString then the other override in the derived class ToString.

Simple example where each class would be in their own file.

public abstract class Human  
{  
    public string FirstName { get; set; }  
    public string LastName { get; set; }  
    public override string ToString() => $"{FirstName} {LastName}";  
}  
  
public class Employee : Human  
{  
    // uses base ToString  
}  
  
public class Manager : Human  
{  
    public override string ToString() => $"{LastName} {FirstName}";  
}

Then to see how this works

Employee employee = new Employee() { FirstName = "Jim", LastName = "Gallagher" };  
Console.WriteLine(employee);  
Manager manager = new Manager() { FirstName = "Karen", LastName = "Payne" };  
Console.WriteLine(manager);

I used an abstract class rather than an interface because you can't implement override ToString with an interface.

Raymond Gilbers 176 Reputation points

2022-07-11T17:43:35.877+00:00

I have accepted your answer because I trully beleive you fixed my issue once again. But at the moment I'm in short amount of spare time and not the best internet. Later this week I will nail it for sure.

Answer 2

Raymond Gilbers 176

With unit testing you mean testing the code for bugs?

Karen Payne MVP 35,606 Reputation points Volunteer Moderator

2022-07-15T12:16:47.857+00:00

The goal of writing unit test to ensure all bases are covered so there is no bugs in code. When writing a unit test say to connect to a database one test with a valid connection and the other with a bad connection and event one for timeouts. In other cases unit test may have you find areas that need more or less assertions.

Here is a simple unit test class for EF Core QueryFilters. And this one for working with json.

Answer 3

Raymond Gilbers 176

I think I need some training and a bit more advance as just a hello world example. I see I get really good suggestions on questions I ask here but I get stuck at certain terminology and understanding how to apply those suggestions. And looking at the MSDN library I have the same issue.
The basics I understand but making a program like I'm making at the moment I should need more knowledge and understanding. Nevertheless I'm pretty far with what I wanted to accomplish with the program I made.

If anybody (if I may ask) knows some good online training please feel free to tell me some of those.

Karen Payne MVP 35,606 Reputation points Volunteer Moderator

2022-07-14T22:21:36.503+00:00

In regards to more training, one piece of advice is to go through Stackoverflow post, find something you have never worked with before.

For instance NuGet package for FluentValidation, read the documentation followed by writing validation methods which can lead to NuGet package Bogus to setup data for validating. Couple this with learning proper unit testing which many developers avoid.

Once you have successfully learned the above, write it out which solidifies the learning experience.

Then create a GitHub repository like this one.

Or create one GitHub repository like this one, document the code for later referencing.

Bottom line is sites such as Pluralsight are great but nothing beats challenging yourself to things like what is abstract, working with Interfaces, generics etc.
Raymond Gilbers 176 Reputation points

2022-07-15T10:56:21.017+00:00

Thanks for the advice it is much appreciated. ok FluentValidation, Bogus "unit testing" i'm lost with these terms hahahah. I'll follow up your advice for sure!
Karen Payne MVP 35,606 Reputation points Volunteer Moderator

2022-07-15T11:08:44.867+00:00

Many developers/coders never consider unit testing as they feel no need or it takes too much time. One of my basic rules is to have unit test for all projects I work on. The number one benefit is you will have tight code when done right. To make things easy to start is using a custom project template. Here is an example of a unit test project for FluentValidation.

Do not feel bad about being lost but if nothing else take time with these and you will be writing better code in no time.

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Error using public override string ToString

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