c# - How to quickly get count of the char in string

The fastest way in c# (counts the commas here):

string s = "Added on Monday, December 20, 2021 2:19:21 PM";
int count = note.Location.Count( x => x == ',' );

Output:

2

C# - How to initialize List items in new statement

One possibility:

image.Normalize( new List() { new Rectangle( 100, 100, 300, 100 ) }  );

Another possibility with setting accessible properties by name:

image.Normalize( new List()
{ 
  new Rectangle() { X=100, Y=100, Width=300, Height=100 }, 
  new Rectangle() { X=200, Y=250, Width=200, Height=50 }
}  
);

C# - How to use generic Min(), Max()

shape.Saved_Width =
 Math.Abs( shape.Points.Max( item => item.Draw_X )-shape.Points.Min( item => item.Draw_X ) );

C# - How to sort generic list by item value

private List<ConstellationIndex> ConstellationsIndex = new List<ConstellationIndex>();
...
this.ConstellationsIndex.Sort( (x, y) => x.Constellation.CompareTo( y.Constellation ) );