System.InvalidOperationException: 'Sequence contains no Element-CodePudding

I am tying to access element but I am getting

System.InvalidOperationException: 'Sequence contains no elements

Please help - Below is the code

var highestCleredFormId = dataUpdates.Where(dat => dat.IsCleared).Select(dat => dat.ID).Max();

CodePudding user response：

The error is pretty clear - in this case dataUpdates.Where(dat => dat.IsCleared) has no elements. That is, dataUpdates has no elements where the IsCleared member has a value of true. Check if there are any elements first, and then get the max:

var clearedDataUpdates = dataUpdates.Where(dat => dat.IsCleared).ToList();

if (clearedDataUpdates.Any())
{
   var highestClearedFormId = clearedDataUpdates.Select(dat => dat.ID).Max();
   // ...
}

CodePudding user response：

This exception occurs when .Max() is called on an empty sequence..

Use DefaultIfEmpty before Max

var highestCleredFormId = dataUpdates
                          .Where(dat => dat.IsCleared)
                          .Select(dat => dat.ID)
                          .DefaultIfEmpty()
                          .Max();

CodePudding user response：

This is probably because dataUpdates.Where(dat => dat.IsCleared) is empty, please check if any of the object has IsCleared as true

You can have null check after Where clause

dataUpdates.Where(dat => dat.IsCleared)?.Select(dat => dat.ID).Max();