Possible unintended reference comparison

I have the following code which gives a warning

Possible unintended reference comparison; to get a value comparison, cast the left hand side to type 'string'`

if (lblStatus.Content == "ACTIVE")
{
  //Do stuff
}
else
{
  //Do other Stuff
}

I'm assuming the warning is because lblStatus.Content may not necessarily always be of type string?

I've tried to fix it using each of the following but I still get a warning

if (lblStatus.Content.ToString() == "ACTIVE")
if ((string)lblStatus.Content == "ACTIVE")
if (lblStatus.Content === "ACTIVE")

Please could someone explain the reason I still get a warning and the best practical way to deal with this?

The warning is because the compile-time type of lblStatus.Content is object. Therefore operator overloading chooses the ==(object, object) overload which is just a reference identity comparison. This has nothing to do with what the execution-time type of the value is.

The first or second of your options should have fixed the warning though:

if (lblStatus.Content.ToString() == "ACTIVE")
if ((string)lblStatus.Content == "ACTIVE")

Note that the first of these will throw an exception if lblStatus.Content is null. I would prefer the second form.

If you think you're still seeing a warning at that point, I suspect you either haven't rebuilt - or something is still "dirty" in your build. A full rebuild absolutely should remove the warning.

I prefer to stick the string.Equals(string,string,StringComparison) method, like the following:

    string contentStr = (lblStatus.Content ?? string.Empty).ToString();
    if (string.Equals("ACTIVE", contentStr, StringComparison.OrdinalIgnoreCase))
    { 
        // stuff
    } 

because it explicitely states what it does + it doesn't give a warning you've mentioned.