Getting Row Index for LINQ Query using Custom Object

Question

I have the following LINQ query to receive indexes:

fieldIndexes = this.record.Fields.Where(a => !a.IsCodeField)
                                 .OrderBy(a => a.DatabaseIndex)
                                 .Select(a => a.DatabaseIndex - 1)
                                 .ToArray();

But I want to replace the a.DatabaseIndex with the actual index of the search. I am aware of the syntax .Select((a, index) => new (index, a))... but I am not sure how to cast the a here to be of my type which in this case is Field. I have tried:

fieldIndexes = this.record.Fields.Select((a, index) => new {index, a})
                                 .Where(a => !a.IsCodeField) // <- Invalid Cast. 
                                 .OrderBy(a => a.DatabaseIndex)
                                 .Select(a => a.DatabaseIndex - 1)
                                 .ToArray();

How can I cast a to my type within the LINQ statement?

Thanks for your time.

Andrei · Accepted Answer · 2014-03-25 12:06:09Z

5

In the Where clause you are working with your newly created anonymous objects with properties a and index, which you can use:

.Where(a => !a.a.IsCodeField)

Of course this can be done in more readable fasion:

fieldIndexes = this.record.Fields.Select((a, index) => new {Index = index, Field = a})
                                 .Where(a => !a.Field.IsCodeField)
                                 ...

answered Mar 25, 2014 at 12:06

Andrei

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Sergey Berezovskiy · Accepted Answer · 2014-03-25 12:06:26Z

3

You are projecting sequence items to anonymous objects with properties index and a. Original item will be accessible via property a:

fieldIndexes = this.record.Fields.Select((a, index) => new {index, a})
                                 .Where(x => !x.a.IsCodeField)

answered Mar 25, 2014 at 12:06

Sergey Berezovskiy

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