I have an object that traverses a list using foreach and returns the value of the object I'm accessing.

Depending on the case, the object returns a count = 10, for example.

I need to summarize the values ​​of all these records and I'm trying as follows, but it returns nothing.

If I remove the = and leave only =, I only retrieve the first record.

How can I summarize all the records?

public decimal? ValesDisponiveis
{
    get
    {
        decimal? informacaoRetorno = null;

        if (ValeCreditos != null)
        {
            foreach (ValeCredito vale in ValeCreditos)
            {
                informacaoRetorno  = vale.ValesDisponiveis;
            }
        }
        return informacaoRetorno;
    }
} 

CodePudding user response：

The problem is:

decimal? informacaoRetorno = null;

Instead use:

decimal? informacaoRetorno = 0;

Or in this case better without nullable because initialization with 0:

decimal informacaoRetorno = 0;

Edit

As mentioned in the comments if you still want null as a valid result if the IEnumerable is null you still can do the following:

if (ValeCreditos == null)
        return null;
    
return ValeCreditors.Sum(x => x.ValesDisponiveis);

If ValesDisponiveis has already the correct base type.

CodePudding user response：

Assuming that you want to return null in case there's no items to be summed (say, when ValeCreditos is empty) you should check for HasValue:

public decimal? ValesDisponiveis
{
    get
    {
        decimal? informacaoRetorno = null;

        if (ValeCreditos != null)
        {
            foreach (ValeCredito vale in ValeCreditos)
            {
                if (informacaoRetorno.HasValue) // business as usual: just add
                    informacaoRetorno  = vale.ValesDisponiveis;
                else // null   value == null, that's why we assign
                    informacaoRetorno = vale.ValesDisponiveis;
            }
        }
        return informacaoRetorno;
    }
}

This code returns null on null or empty ValeCreditos and sum of items otherwise.