Condition == Null [closed]

by

Hello guys i have a condition with code like this

LogBase o = null;
lock (_logQueue)
{
    o = _logQueue.Dequeue();
}
if (o == null) continue;

try
{
    switch (o.DataType)
    {
        case LogType.INFO:
            Log(o);
            break;
        case LogType.ERROR:
            LogException(o);
            break;
        default:
            break;
    }
}

there always showing message “cant be null value”, i guess i need to change condition o == null

i dont know any else method to replace, can anyone help me please? thanks

  • Which line generates the error? What is LogBase? It’s hard to solve problems with code that we cannot see, and a few lines that are out of context with variables that are not declared is pretty difficult. See minimal reproducible example and How to Ask, and then edit your post. Also, you’ll find your experiences will be much better if you take the time to go through the tour and read the help center pages to learn how the site works before you begin posting.

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  • @KenWhite OP clearly states, that the question is about the o == null-condition.

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  • 2

    @MakePeaceGreatAgain: So? There is still no minimal reproducible example accompanying the question, and it contains unknown types.

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  • 1

    I assume the warning is because _logQueue.Dequeue(); never returns null, wich makes the o == null-check obsolete. However without actually knowing what _logQueue is, that is just a guess. Anyway locking the exact same reference as you’re using within a lock is a really bad idea, IMHO.

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To address the issue of the “null” value causing the error message, you can add a null check before accessing the DataType property of the o object. Here’s how you can modify the code:

LogBase o = null;
lock (_logQueue)
{
    o = _logQueue.Dequeue();
}
if (o == null) continue;

try
{
    if (o != null) // Add null check here
    {
        switch (o.DataType)
        {
            case LogType.INFO:
                Log(o);
                break;
            case LogType.ERROR:
                LogException(o);
                break;
            default:
                break;
        }
    }
}

By adding the null check if (o != null), you ensure that you only attempt to access the DataType property if o is not null, thus avoiding the error message.

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