private float _PhAvg;

_pHAVg assign

_PhAvg = DatabaseReader._Parameters
    .SingleOrDefault(x => x.SpecificReg == RegCodes.phScode)
    ?.CurrentValue?.Average() ?? -9999; 

check _pHAvg

Console.WriteLine("pH :" _pHAVg); Output pH:6,77

Call method

Task.Run(() => _SampleCheck.SampleLimitCheck(_PhAvg, _AkmAvg, _CodAvg));

And that is SampleLimitCheck method

public void SampleLimitCheck(float PhAverage, float AkmAverage, float CodAverage)
{
    Console.WriteLine("pH :"   PhAverage);
}

Check PhAverage

Console.WriteLine("pH :" PhAverage); Output pH:0

I give float values to the function sometimes correct but some times appear as 0 in the function.

When I call Task.Run(() => _SampleCheck.SampleLimitCheck(_PhAvg, _AkmAvg, _CodAvg)); I see values are 0 in function. Not all the times. Sometimes 0 sometimes I get the correct values.

But when I call _SampleCheck.SampleLimitCheck(_PhAvg, _AkmAvg, _CodAvg) I always catch the correct value.

What is wrong with Task.Run()?

CodePudding user response：

Not knowing how the code proceeds is a little difficult to know what it might be.

But since it's a Task, I can guess why you're reading the result before it's ready.

Task.Run(() => _SampleCheck.SampleLimitCheck(_PhAvg, _AkmAvg, _CodAvg)); Debug.WriteLine("-----");

In this example even before _SampleCheck.SampleLimitCheck finishes the Debug will be run.

If you need the result you must make sure the task is finished first.

CodePudding user response：

As it's currently written, it's hard to know exactly what you're question.

I guess

• _PhAvg is member field.
• Run.Task is executed before the correct value is obtained in the asynchronous thread, so _PhAvg is member default value.

Wrong code

Task.Run(() => _PhAvg = 10);
Task.Run(() => _SampleCheck.SampleLimitCheck(_PhAvg, _AkmAvg, _CodAvg));

Right code

await Task.Run(() => _PhAvg = 10);
await Task.Run(() => _SampleCheck.SampleLimitCheck(_PhAvg, _AkmAvg, _CodAvg));

The principle is to ensure that the _PhAvg assignment must precede the Task.Run.