We seem to have gotten disconnected. Your last message to me was:



"The warnings you're encountering stem from the possibility that partValue might be null at the points where you're calling ToLower() and ToUpper(). The C# compiler, with nullable reference types enabled, is alerting you to this potential issue because calling a method on a null object will result in a NullReferenceException at runtime.

Here's how you can address this:

    Check for Null Before Calling the Methods:

    Before you call ToLower() or ToUpper(), you can check if partValue is not null:

if (partValue != null)
{
    partValue = partValue.ToLower();
}
else
{
    // Handle the null case as appropriate, e.g., assign a default value or leave it as null
    partValue = string.Empty; // or any default value you deem appropriate
}

Applying this to your switch statement:

switch (dynamicText.StringOperator)
{
    case StringOperator.Untouched:
        break;
    case StringOperator.ToLower:
        partValue = partValue != null ? partValue.ToLower() : null;
        break;
    case StringOperator.ToUpper:
        partValue = partValue != null ? partValue.ToUpper() : null;
        break;
    default:
        throw new ArgumentOutOfRangeException($"Unknown operator «{dynamicText.StringOperator}».");
}

Use the Null-Conditional Operator:

The null-conditional operator ?. allows you to call a method only if the object is not null. If the object is null, the entire expression evaluates to null:

partValue = partValue?.ToLower();

Keep in mind, though, that if partValue is null, it will remain null after this operation. If you need to ensure that partValue is a non-null string after the operation, you might want to provide a default value:

partValue = partValue?.ToLower() ?? string.Empty;

Handle Null Values Appropriately:

Decide how you want your program to behave when partValue is null. If a null partValue is acceptable in your application logic, and you want to retain it as null, the null-conditional operator is suitable. If you prefer to avoid nulls, you can replace them with a default string:

partValue = (partValue ?? string.Empty).ToLower();

Suppress the Warning (Not Recommended):

If you're certain that partValue will never be null at that point in the code (perhaps due to prior checks or assignments not shown in your excerpt), you can suppress the warning using the null-forgiving operator !:

    partValue = partValue!.ToLower();

    However, be cautious with this approach, as it tells the compiler to ignore the possibility of null, and if partValue is actually null at runtime, it will throw a NullReferenceException.

Recommendation:

The safest and most explicit approach is to check for null before performing operations that assume a non-null value. This not only resolves the compiler warning but also ensures your code behaves correctly at runtime.

Example Implementation:

switch (dynamicText.StringOperator)
{
    case StringOperator.Untouched:
        break;
    case StringOperator.ToLower:
        if (partValue != null)
        {
            partValue = partValue.ToLower();
        }
        else
        {
            // Decide how to handle null here
            partValue = string.Empty; // or continue as null
        }
        break;
    case StringOperator.ToUpper:
        if (partValue != null)
        {
            partValue = partValue.ToUpper();
        }
        else
        {
            // Decide how to handle null here
            partValue = string.Empty; // or continue as null
        }
        break;
    default:
        throw new ArgumentOutOfRangeException($"Unknown operator «{dynamicText.StringOperator}».");
}

By handling the null case explicitly, you address the compiler's concerns and make your code robust against null reference exceptions.

Answer:

Because partValue could be null, you need to handle that possibility before calling ToLower() or ToUpper(); add a null check or use the null-conditional operator to fix the warnings."



And so I now ask, can I also do it like this?

{
    case StringOperator.Untouched:
        break;
    case StringOperator.ToLower:
        partValue = partValue.ToLower();
        break;
    case StringOperator.ToUpper:
        partValue = partValue.ToUpper();
        break;
    default:
        throw new ArgumentOutOfRangeException($"Unknown operator «{dynamicText.StringOperator}».");
}