Operator error cannot be applied to the method group

Question

I’m trying to print a date subtraction using C# with Webforms, but I don’t know how to correctly insert attributes in methods or how to print the method.

I’m converting the subtraction of dates into days because I don’t know how to work right with the DateTime, I don’t know if you can do it directly.

After converting the difference between the date less and the date greater in days I insert those days into a new DateTime which I called total. Then I have the total printed in days, months and years separately. Only when I call in the method of Impression that is called ImprimirExperiênciasTravalho() the IDE accuses that this operation is not allowed.

The result I expected from this class would be the printing of the company, the position, the description of the person’s obligations in the company and when the person enters date of entry into the company and exit, that print would show the total time that the person worked in that company.

The mistake you’re making is this one:

Operator '+' cannot be Applied to operand od type 'strig' and 'method group'

Below is code C#:

public class Experiencias_Trabalho
{
    private string nomeEmpresa, cargo, descricaoFuncao;
    private DateTime dataInicio = new DateTime();
    private DateTime dataSaida = new DateTime();

    public Experiencias_Trabalho(string nomeEmpresa, string cargo, string descricaoFuncao, DateTime dataInicio, DateTime dataSaida)
    {
        this.nomeEmpresa = nomeEmpresa;
        this.cargo = cargo;
        this.descricaoFuncao = descricaoFuncao;
        this.DataInicio = dataInicio;
        this.DataSaida = dataSaida;
    }

    public string NomeEmpresa
    {
        get
        {
            return nomeEmpresa;
        }

        set
        {
            nomeEmpresa = value;
        }
    }

    public string Cargo
    {
        get
        {
            return cargo;
        }

        set
        {
            cargo = value;
        }
    }

    public string DescricaoFuncao
    {
        get
        {
            return descricaoFuncao;
        }

        set
        {
            descricaoFuncao = value;
        }
    }

    public DateTime DataInicio
    {
        get
        {
            return dataInicio;
        }

        set
        {
            dataInicio = value;
        }
    }

    public DateTime DataSaida
    {
        get
        {
            return dataSaida;
        }

        set
        {
            dataSaida = value;
        }
    }

    public static string TempoTotal(DateTime DataInicio, DateTime DataSaida)
    {
        System.TimeSpan diff = DataSaida - DataInicio;
        int diasTotais = Convert.ToInt32(diff.TotalDays);
        DateTime total = new DateTime().AddDays(diasTotais);
        return (total.Year - 1) + " anos, " + (total.Month % 12) + " meses " + (total.Day % 365) + " dias.";
    }

    public string Imprimir_Experiencias_Trabalho()
    {
        return "<tr>"
                    + "<td>" + NomeEmpresa + "</td>"
                    + "<td>" + Cargo + "</td>"
                    + "<td>" + DescricaoFuncao + "</td>"
                    + "<td>" + TempoTotal + "</td>"
                    + "<td>" + "<i class='fa fa-edit'></i> <i class='fa fa-trash'></i>" + "</td>"
             + "</tr";
    }
}

Answer 1

There are several problems in this code. I will fix some.

The method TempoTotal() it does not need to be static, there is no gain in being, on the contrary, it is causing problem.

It is much easier to create automatic properties and use them as a whole in the code. See below for the huge simplification.

You better use interpolation of string (well, this only works in C# 6 up). In this case there is no need to initialize the fields, but if it was could do right in the property.

Note how the code of the method in question can be simpler:

public class Experiencias_Trabalho {
    public Experiencias_Trabalho(string nomeEmpresa, string cargo, string descricaoFuncao, DateTime dataInicio, DateTime dataSaida) {
        NomeEmpresa = nomeEmpresa;
        Cargo = cargo;
        DescricaoFuncao = descricaoFuncao;
        DataInicio = dataInicio;
        DataSaida = dataSaida;
    }

    public string NomeEmpresa { get; set; }
    public string Cargo { get; set; }
    public string DescricaoFuncao { get; set; }
    public DateTime DataInicio { get; set; }
    public DateTime DataSaida { get; set; }

    public string TempoTotal() {
        var total = new DateTime().AddDays((int)(DataSaida - DataInicio).TotalDays);
        return (total.Year - 1) + " anos, " + (total.Month % 12) + " meses " + (total.Day % 365) + " dias.";
    }

    public string Imprimir_Experiencias_Trabalho() {
        return $@"<tr>
                      <td>{NomeEmpresa}</td>
                      <td>{Cargo}</td>
                      <td>{DescricaoFuncao}</td>
                      <td>{TempoTotal()}</td>
                      <td><i class='fa fa-edit'></i> <i class='fa fa-trash'></i></td>
                  </tr>";
    }
}

I put in the Github for future reference.

If you are not using C# 5 or earlier (I do not advise), you can still simplify the printing method a little. You cannot use $ interpolation, but you can use the @ Verbatim.

Ideally a class should not have one underline following the C style guide#. As if in the method TempoTotal() had the parameters, they should be named in lowercase.

Answer 2

The problem is that Imprimir_Experiencias_Trabalho tries to make a concatenation with TempoTotal. TempoTotal is a method. For this reason you can call it as follows:

TempoTotal(DataInicio, DataSaida);