Unhandled exception. System.collections.generic.keynotfoundexception: the given key 'string team' was not present in the dictionary.

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The problem I face is that when I type an input for the player's name then the error message shows

<pre><pre>nhandled exception. System.Collections.Generic.KeyNotFoundException: The given key 'string team' was not present in the dictionary.
   at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
   at Program.<<Main>$>g__AddPlayer|0_5(String team, <>c__DisplayClass0_0& ) in /Users/ten/Desktop/NMAD/homework3-stybjs/Program.cs:line 153
   at Program.<Main>$(String[] args) in /Users/ten/Desktop/NMAD/homework3-stybjs/Program.cs:line 28

Original code for Dictionary & switch case menu

C#

void AddTeam()
{
    Console.Write("Do you want to add a team? (Y/N): ");
    string answer = Console.ReadLine().ToLower();
    if (answer == "y")
    {
        Console.Write("Enter a team name: ");
        string teamName = Console.ReadLine();
        if (teams.ContainsKey(teamName))
        {
            Console.WriteLine("Team already exists.");
            return;
        }
        else
        {
            teams.Add(teamName, new Team(teamName));
            // Team team = new Team(teamName);
            // teams.Add(teamName, team);
        }
    }
    else if (answer == "n")
    {
        Console.WriteLine("Add Team cancelled");
        return;
    }
    else
    {
        Console.WriteLine("Invalid selection. Please only enter Y or N.");
        AddTeam();
    }
}

C#

case "1":
            AddTeam();
            AddPlayer("string team");

C#

void string PromptPlayerName(string team)
{
    while(true)
    {
        Console.Write("Enter a player name: ");
        string playerName = Console.ReadLine();

        if(teams.ContainsKey(team))
        {
            if(teams[team].Players.ContainsKey(playerName)) 
            {
                Console.WriteLine($"The player's name {playerName} already exist on the team {team}");
                continue;
            }
        }
        return playerName;
    }
}

int PromptPlayerJersey(string team)
{
    while(true)
    {
        Console.Write("Enter a player's jersey number: ");
        string playerJersey = Console.ReadLine();
        if (int.TryParse(playerJersey, out int playerJerseyInt) && playerJerseyInt >= 0 && playerJerseyInt <= 99)
        {
            if(teams.ContainsKey(team))
            {
                if(teams[team].Players.ContainsKey(playerJersey)) 
                {
                    Console.WriteLine($"The player's jersey number {playerJersey} already exist on the team {team}");
                    continue;
                }
            }
            return playerJerseyInt;
        }
        else
        {
            Console.WriteLine("Invalid selection. Please only enter a valid number between 0-99.");
            continue;
        }
    }
}

string PromptPlayerPosition(string team)
{
    while(true)
    {
        Console.Write("Enter a player position: ");
        string playerPosition = Console.ReadLine();
        
        if(teams.ContainsKey(team))
        {
            if(teams[team].Players.ContainsKey(playerPosition)) 
            {
                Console.WriteLine($"The player's position {playerPosition} already exist on the team {team}");
                continue;
            }
        }
        return playerPosition;
    }
}

C#

void AddPlayer(string team)
{
    string playerName = PromptPlayerName(team);
    int playerJersey = PromptPlayerJersey(team);
    string position = PromptPlayerPosition(team);
    // re-prompt if user want to add another player
    Console.Write("Do you want to add another player? (Y/N): ");
    string answer = Console.ReadLine().ToLower();
    if (answer == "y")
    {
        AddPlayer(team);
    }
    else if (answer == "n")
    {
        Console.WriteLine("Add Player cancelled");
        return;
    }
    else
    {
        Console.WriteLine("Invalid selection. Please only enter Y or N.");
        AddPlayer(team);
    }
    // Player player = new Player(playerName, playerJersey, position);
    // players.Add(playerName, player);
    teams[team].Players.Add(playerName, new Player(playerName, playerJersey, position));
}

C#

void AddPlayer(string team)
{
    string playerName = PromptPlayerName(team);
    int playerJersey = PromptPlayerJersey(team);
    string position = PromptPlayerPosition(team);
    teams[team].Players.Add(playerName, new Player(playerName, playerJersey, position));

    while(true)
    {
        Console.Write("Do you want to add another player? (Y/N): ");
        string answer = Console.ReadLine().ToLower();
        if (answer == "y")
        {
            AddPlayer(team);
            teams[team].Players.Add(playerName, new Player(playerName, playerJersey, position));
        }
        if (answer == "n")
        {
            teams[team].Players.Add(playerName, new Player(playerName, playerJersey, position));
            Console.WriteLine("Add Player cancelled");
            return;
        }
        else
        {
            Console.WriteLine("Invalid selection. Please only enter Y or N.");
            continue;
        }
    }
}

What I have tried:

I have tried to use a simple one:

if (players.ContainsKey(playerName))
            {
                Console.WriteLine("Player already exists.");
                continue;
            }

However, when I ran a code and it won't display a player's name in:

C#

<pre>void ListTeamRoster()
{  
    Console.Write("Enter a team name to list roster: ");
    string teamName = Console.ReadLine();

    if (teams.ContainsKey(teamName))
    {
            foreach (KeyValuePair<string, Team> team in teams)

            {
                if (team.Key == teamName)
                {
                    Console.WriteLine($"{team.Value.ToString()}");
                }
            }
    }
    else
    {
        Console.WriteLine($"{teamName} does not exist.");
        return;
    }
}

I am unable to figure it out how exactly have my code gone wrong.

Posted 22-Nov-22 12:18pm

stybjs

Updated 22-Nov-22 22:13pm

v4

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Comments

Graeme_Grant 22-Nov-22 19:15pm

How did you define the teams dictionary? It is suggesting that the key is not a string type. Please update your question so that we can see.

stybjs 23-Nov-22 2:08am

what can I do to update my question so you can see it? what specific are you looking for? Let me know what I can show it to you.

Graeme_Grant 23-Nov-22 2:36am

Again, how did you define the teams dictionary?

stybjs 23-Nov-22 2:42am

Well, I define the teams dictionary as a bundle of coaches and players while it is also held a list of team names for coaches and players. Therefore, I am using it to insert in team.value for displaying all info. That is my understanding of using the teams dictionary.

Graeme_Grant 23-Nov-22 4:38am

I can not see your screen. You need to update your question if you want help.

stybjs 23-Nov-22 5:24am

okay, i will add picture

stybjs 23-Nov-22 5:27am

what screen do you referring to? I need to understand what screen you can't see it.

Graeme_Grant 23-Nov-22 7:02am

🤦‍♂️ I can't see your screen (computer monitor) in this Q&A. You need to update your question with the information requested.

Sandeep Mewara 23-Nov-22 0:19am

Apart from what Graeme asked above, I am lost with your AddPlayer code. You recursively keep on calling Addplayer on saying yes. Is that even working? Pretty sure, method should add one person at a time when asked instead of going into recurrsive loop.

stybjs 23-Nov-22 2:09am

so you means i should modify it when it asks if the user wants to add another player?

Sandeep Mewara 23-Nov-22 2:30am

to start with, its just the execution you need continue and not call AddPlayer again if yes.

1 solution

Add a Solution

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Richard Deeming · Answer 1 · 2022-11-22T22:13:00

Solution 1

You ask the user to enter a team name, and add an entry to the dictionary using the entered value as the key.

You then try to add a player to the team called "string team", regardless of what the user typed.

Unless the user entered "string team" as the team name, that will not work.

Change your AddTeam method so that it either returns the team name entered by the user, or returns the Team object itself:

C#

string AddTeam()
{
    Console.Write("Do you want to add a team? (Y/N): ");
    while (true)
    {
        string answer = Console.ReadLine().ToLower();
        if (answer == "y")
        {
            Console.Write("Enter a team name: ");
            string teamName = Console.ReadLine();
            if (teams.TryGetValue(teamName, out Team team))
            {
                Console.WriteLine("Team already exists.");
            }
            else
            {
                team = new Team(teamName);
                teams.Add(teamName, team);
            }
            
            return team.teamName;
        }
        
        if (answer == "n")
        {
            Console.WriteLine("Add Team cancelled");
            return null;
        }
        
        Console.WriteLine("Invalid selection. Please only enter Y or N.");
    }
}

Check that the returned value is not null, and then pass it to your AddPlayer method:

C#

case "1":
    string teamName = AddTeam();
    if (teamName != null) AddPlayer(teamName);

Edit: For the team roster, you either need to override the ToString method on the Team class, or update the ListTeamRoster method to display the desired details:

C#

void ListTeamRoster()
{  
    Console.Write("Enter a team name to list roster: ");
    string teamName = Console.ReadLine();
    if (!teams.TryGetValue(teamName, out Team team))
    {
        Console.WriteLine($"{teamName} does not exist.");
        return;
    }
    
    Console.WriteLine("Players:");
    foreach (KeyValuePair<string, Player> player in team.Players)
    {
        Console.WriteLine("{0}: {1}", player.Key, player.Value);
    }
    Console.WriteLine();
    
    Console.WriteLine("Coaches:");
    foreach (KeyValuePair<string, Coach> coach in team.Coaches)
    {
        Console.WriteLine("{0}: {1}", coach.Key, coach.Value);
    }
    Console.WriteLine();
}

Posted 22-Nov-22 22:13pm

Richard Deeming

Updated 22-Nov-22 23:21pm

v2

Comments

stybjs 23-Nov-22 5:16am

Hmm, it doesn't solve my problem to display players and coaches because my actual result came out:

Enter a team name to list the roster: Yankees
=======Teams========

Yankees

=======Players========

=======Coaches========

so i want to make it display since I am using ToString from Team class. Only single problem is that they doesn't take two infos into dictionary I have:

 public Dictionary<string, Player> Players = new Dictionary<string, Player>();
    public Dictionary<string, Coach> Coaches = new Dictionary<string, Coach>();

Richard Deeming 23-Nov-22 5:21am

I've updated my answer to show you how to fix your roster method.

stybjs 23-Nov-22 5:27am

okay....

stybjs 23-Nov-22 5:30am

quite good one but not exactly that my code will work that way because I have my override ToString

    public Team(string teamName)
    {
        TeamName = teamName;
    }
    
    public override string ToString()
    {
        string info = $"\n=======Teams========\n";
        info += $"\n{TeamName}\n";

        info += "\n=======Players========\n";
        foreach(KeyValuePair<string, Player> player in Players)
        {
            info += player.Value.ToString();
        }

        info += "\n=======Coaches========\n";
        foreach(KeyValuePair<string, Coach> coach in Coaches)
        {
            info += coach.Value.ToString();
        }
        return info;
    }

this code is actually got from two override ToString (from two different classes)

Richard Deeming 23-Nov-22 5:33am

Using string concatenation in a loop is always a bad idea. But if you've already overridden the ToString method, then you need to explain what the problem is. If it's that you're not seeing any players or coaches in your team, then you need to debug your code to find out why you're not adding them.

stybjs 23-Nov-22 5:37am

I see. I am not using debug for a long time after started to learn C#. I have watched a tutorial about that and am unsure of how to use the red breakpoint to find where it is before hitting the exception. What's your advice?

Richard Deeming 23-Nov-22 5:40am

What exception? The only exception you've mentioned so far is the KeyNotFoundException, which should be fixed if you've followed the advice I initially posted in my answer.

stybjs 23-Nov-22 5:42am

Yes, and I am not sure how exactly can I use debug...I admit that I do not understand fully how to utilize the debug console since it is a little confusing with the breakpoints.

Richard Deeming 23-Nov-22 5:44am

The Microsoft documentation is pretty straightforward:
First look at the debugger - Visual Studio (Windows) | Microsoft Learn[^]

stybjs 23-Nov-22 5:52am

Thanks, but I can't seem to find thrown exception since I tried to find which one is occurring before hitting an exception so I can find what something is not being added. How d you find it if you see or what does it means when I see the variable section shown?

Richard Deeming 23-Nov-22 5:54am

Once again: WHAT EXCEPTION?

The only exception you've mentioned so far is the one I've already solved for you. If you're still getting an exception, then you need to tell us what exception you're getting, and what line it's being thrown from.

If you run your project in Visual Studio using the "Debug" configuration, your code will break when any unhandled exception is thrown, and show you the full details of the exception.

Richard Deeming 23-Nov-22 6:02am

No, I'm not going to download your project to debug it for you.

stybjs 23-Nov-22 5:23am

At this point is that I need to display but something might be wrong with some issues in my code especially:

void AddPlayer(string team)
{
    string playerName = PromptPlayerName(team);
    int playerJersey = PromptPlayerJersey(team);
    string position = PromptPlayerPosition(team);
 
    while(true)
    {
        Console.Write("Do you want to add another player? (Y/N): ");
        string answer = Console.ReadLine().ToLower();
        if (answer == "y")
        {
            AddPlayer(team);
            break;
        }
        if (answer == "n")
        {
            Console.WriteLine("Add Player cancelled");
            return;
        }
        else
        {
            Console.WriteLine("Invalid selection. Please only enter Y or N.");
            continue;
        }
        teams[team].Players.Add(playerName, new Player(playerName, playerJersey, position));
    }
}

Let me know if you need a clarification about my question.

Unhandled exception. System.collections.generic.keynotfoundexception: the given key 'string team' was not present in the dictionary.

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Solution 1

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Unhandled exception. System.collections.generic.keynotfoundexception: the given key 'string team' was not present in the dictionary.

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