C# Delegates Real World Usage

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I've previously asked a question of about Delegates does anyone have a must have scenario where I would have to use a delegate? How does this improve my C# code?

Just as many scenarios I use it in I've always seem to be able to program around it.

Best Answer

Assuming you're not talking about events - of course you can program around it. The point is to make it nicer and cleaner.

protected void Sort()
{
    foreach (string key in _dBase.Keys)
    {
      Array.Sort<Pair<string, Dictionary<string, T>>>(_dBase[key], 
            new Comparison<Pair<string, Dictionary<string, T>>>(
        delegate(Pair<string, Dictionary<string, T>> a, Pair<string, Dictionary<string, T>> b)
        {
            if (a == null && b != null)
                return 1;
            else if (a != null && b == null)
                return -1;
            else if (a == null && b == null)
                return 0;
            else
                return a.First.CompareTo(b.First);
        }));
    }
}

Could I do that without an inline delegate? Sure. Would I have a floppy private method in my class that would only be used for this one instance? Yup.

Edit: As mentioned in the comments, you can simplify:

Array.Sort<Pair<string, Dictionary<string, T>>>(_dBase[key], 
   new Comparison<Pair<string, Dictionary<string, T>>>(
   delegate(Pair<string, Dictionary<string, T>> a, Pair<string, Dictionary<string, T>> b)
   {

Array.Sort<Pair<string, Dictionary<string, T>>>(_dBase[key], (a,b) =>
   {

Related Solutions

C# – Embedding DLLs in a compiled executable

I highly recommend to use Costura.Fody - by far the best and easiest way to embed resources in your assembly. It's available as NuGet package.

Install-Package Costura.Fody

After adding it to the project, it will automatically embed all references that are copied to the output directory into your main assembly. You might want to clean the embedded files by adding a target to your project:

Install-CleanReferencesTarget

You'll also be able to specify whether to include the pdb's, exclude certain assemblies, or extracting the assemblies on the fly. As far as I know, also unmanaged assemblies are supported.

Update

Currently, some people are trying to add support for DNX.

Update 2

For the lastest Fody version, you will need to have MSBuild 16 (so Visual Studio 2019). Fody version 4.2.1 will do MSBuild 15. (reference: Fody is only supported on MSBuild 16 and above. Current version: 15)

C# – LINQ’s Distinct() on a particular property

What if I want to obtain a distinct list based on one or more properties?

Simple! You want to group them and pick a winner out of the group.

List<Person> distinctPeople = allPeople
  .GroupBy(p => p.PersonId)
  .Select(g => g.First())
  .ToList();

If you want to define groups on multiple properties, here's how:

List<Person> distinctPeople = allPeople
  .GroupBy(p => new {p.PersonId, p.FavoriteColor} )
  .Select(g => g.First())
  .ToList();

Note: Certain query providers are unable to resolve that each group must have at least one element, and that First is the appropriate method to call in that situation. If you find yourself working with such a query provider, FirstOrDefault may help get your query through the query provider.

Note2: Consider this answer for an EF Core (prior to EF Core 6) compatible approach. https://stackoverflow.com/a/66529949/8155

Best Answer

Related Solutions

C# – Embedding DLLs in a compiled executable

C# – LINQ’s Distinct() on a particular property

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