Declare variable within LINQ select(x => new

Question

I'm mapping a POCO into a model, code shown below.

// NOT NEEDED var noneRequiredUserDocuments = new List<NoneRequiredUserDocument>(); //var docs = studentDocuments.Where(x => x.RequiredUserDocumentId == null); // NOT NEEDED .ToList(); //var noneRequiredUserDocuments = docs.Select(x => new NoneRequiredUserDocument  // You can chain LINQ methods (i.e. Where and Select) var noneRequiredUserDocuments = studentDocuments     .Where(x => x.RequiredUserDocumentId == null)     .Select(x => new NoneRequiredUserDocument     {         StudentDocument = x,         Src = _storageService.GetFileUrl(x.FileName),         ThumbnailImageUrl = ImageHelper.ThumbnailImageUrl(Src, 75)      }).ToList(); 

My problem is that in this line:

ThumbnailImageUrl = ImageHelper.ThumbnailImageUrl(Src, 75) 

Src doesn't exist in the context.

Is there a way for me to declare a variable within the select that I can the reuse within the LINQ select?

And I don't want to call _storageService.GetFileUrl twice.

Answer 1

You can declare a variable inside a Select like this:-

noneRequiredUserDocuments = docs.Select(x =>    {       var src= _storageService.GetFileUrl(x.FileName);       return new NoneRequiredUserDocument      {         StudentDocument = x,         Src = src,         ThumbnailImageUrl = ImageHelper.ThumbnailImageUrl(src, 75);      };   }).ToList(); 

In query syntax doing this is equivalent to:-

from x in docs let src= _storageService.GetFileUrl(x.FileName) select and so on..