Convert String to Decimal

Question

And I’m having trouble properly converting this string in decimal.

decimal.Parse(txtValor.Text)=meuVen.Valor;

When I put the conversion in front, it shows error after the =. I don’t know how to convert the second part, or if I should change the second part instead of the first.

The teacher’s code is:

private void Leitura2() 
{ 
    txtCod2.Text = dgvRegistros2.Rows[dgvRegistros2.CurrentRow.Index].Cells["codigo_servico"].Value‌​.ToString(); 
    Vendas meuVen = new Vendas(int.Parse(txtCod2.Text)); 
    txtNome.Text = meuVen.Nome; 
    decimal.Parse(txtValor.Text) = meuVen.Valor; 
    txtEntrega.Text = meuVen.Entrega.ToString("dd/MM/yyyy"); 
}

Answer 1

You may not have found the right method to do the conversion. It even works but it is not usually the right one. If something invalid is entered and the conversion will generate an exception. In general it is a mistake to try to capture an exception just because the value is invalid. So the best method is this:

decimal valorDecimal;
if (decimal.TryParse(txtValor.Text, out valorDecimal)) {
    meuVen.Valor = valorDecimal; //note que você quer atribuir o resultado a uma variável
} else {
    //faz um tratamento de erro aqui
}

I put in the Github for future reference.

See the difference between the two methods and how it works.

To assign a value to a variable it must be on the left always. So in this case you read backwards: "is assigning the valorDecimal for meuVen.Valor.

We could have helped more with a larger context.

The doubt is indeed basic and this is worrisome because it is not by the use of the method but by how to write an assignment. With such a basic error, it will be difficult to do more sophisticated things, such as treat error. And worse, identify when there is potential for error, test correctly to ensure that the program works correctly in all situations and not only in optimal condition.

Answer 2

convert this into a class and start building libraries from all the code you implement for each project you do. so do not write the same code several times

public void ConvertStringDecimal(string stringVal) {
        decimal decimalVal = 0;

        try {
            decimalVal = System.Convert.ToDecimal(stringVal);
            System.Console.WriteLine(
                "The string as a decimal is {0}.", decimalVal);
        } 
        catch (System.OverflowException){
            System.Console.WriteLine(
                "The conversion from string to decimal overflowed.");
        }
        catch (System.FormatException) {
            System.Console.WriteLine(
                "The string is not formatted as a decimal.");
        }
        catch (System.ArgumentNullException) {
            System.Console.WriteLine(
                "The string is null.");
        }

        // Decimal to string conversion will not overflow.
        stringVal = System.Convert.ToString(decimalVal);
        System.Console.WriteLine(
            "The decimal as a string is {0}.", stringVal);
    }   

Answer 3

In the end, I discovered that there was no need for conversion in that form, I redid all the "Cs" and "form" for sales and only in one of them with the help of a button I was able to accomplish the sum. I ended up using the following method:

private void btnCalc_Click(object sender, EventArgs e)
    {
        decimal vl1, vl2, result;
        vl1 = decimal.Parse(txtValor.Text);
        vl2 = decimal.Parse(txtValProd.Text);

        result = vl1 + vl2;
        txtValtotal.Text = (result.ToString());

    }

Answer 4

   System.Convert.ToDecimal(stringVal);