Fulproof questions

• Why is this error "local variable cannot be declared in this scope because it ... is already used"?
• Why decrementing one variable modifies incrementing of another one in C# Parallel.ForEach loop?
• Why should I specify <type> in Method<type>() ? And how can it be used? [closed]
• How to search for all files containing 2 specific strings?
• Why would you use an immutable value in a dictionary?
• How ToLookup() with multiple indexes?
• How to get the reference of TPL task's thread in C#?
• Can you advise me a resource with LINQ/lambda code exercises? [closed]
• What is the difference in .NET between developing a multithreaded application and parallel programming?
• How to sort in a WPF ListBox?

Fulproof answers