CODEWITHSUNDEEP
c#list
mebetop
mebetop

Reputation: 13

Need help to display the contents of a list in a textbox

I'm trying to display the names of 10 people in a windows form app textbox. The last line of code gives me the following 2 errors:

The best overloaded method match for 'string.Join(string, string[])' has some invalid arguments.

Argument 2: cannot convert from 'System.Collections.Generic.List' to 'string[]'.

Can someone explain the errors and a how to fix them?

public class FullName
{
    public string name;
    public string surname;
}

int i;
List<FullName> namesList = new List<FullName>();

for (i = 0; i < 10; i++)
{
    namesList.Add(new FullName { name = "John", surname = "Adams" });
}

txt_names.Text = String.Join(" ", namesList);

Upvotes: 1

Views: 57

Answers (3)

Arslan Munir
Arslan Munir

Reputation: 467

You are passing Generic list as the second argument to String.Join(), while it accepts an array of strings.

So Instead of

txt_names.Text = String.Join(" ", namesList);

You could correct this by using a simple LINQ extension method.

txt_names.Text = String.Join(" ", namesList.Select(x=> $"{x.Name} {x.SurName}");

and the rest will go fine.

Upvotes: 0

Arphile
Arphile

Reputation: 861

Use override to make string beautify

public class FullName
{
    public String Name { get; set; }
    public String SurName { get; set; }

    public override string ToString()
    {
        return String.Format("{0} {1}", Name, SurName);
    }
}

after you override ToString() method you can just call class to print it.

List<FullName> Names = new List<FullName>();
for ( int i = 0; i < 10; i++ )
{
     Names.Add(new FullName() { Name = "John", SurName = "Smith" });
}
Console.WriteLine(String.Join("\r\n", Names));

Result >

John Smith
John Smith
John Smith
John Smith
John Smith
John Smith
John Smith
John Smith
John Smith
John Smith

Upvotes: 1

Rohit Garg
Rohit Garg

Reputation: 493

String.Join expects a list of strings to join. You are giving a list of FullName right now.

You can try:

String.Join(",", namesList.Select(m => m.name).ToArray());

And if you want name and surname both, you can simply append it:

String.Join(",", namesList.Select(m => m.name + m.surname).ToArray());

Upvotes: 1

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