sql server - How to count only rows where are non-zero value

In SELECT use this construction with CASE statement:

...
count(*) as rowscount,

sum( case a.costamount when 0 then 0 else 1 end ) as rowscount_nonzero

Visual Studio - How to disable expand/collapse in editor ?

All these checkboxes to false.

c# - How convert string array into one string

If you use this code on string array:

string[] args = Environment.GetCommandLineArgs();      
Console.Write( args.ToString() );

you will get:

System.String[]

But better way in this case is to use string.Join() function (where you can set used delimiter):

string[] args = Environment.GetCommandLineArgs();      
Console.Write( string.Join( ",", args ) );

Then:

C:\app.dll,layoutdir=C:/app/bin

c# - How get important system informations

Sometimes you need for example width of the standard scrollbar. For getting it you can use SystemInformation class (WinForms). Here is a list of supported properties and their values.

Type t = typeof( System.Windows.Forms.SystemInformation );            
PropertyInfo[] property = t.GetProperties();

for( int i = 0; i < property.Length; i++ )
  richTextBox1.Text += property[ i ].Name + " = " + 
  property[ i ].GetValue( null, null ).ToString() + "\n";        

Output:

DragFullWindows = True
HighContrast = False
MouseWheelScrollLines = 3
PrimaryMonitorSize = {Width=1920, Height=1080}
VerticalScrollBarWidth = 17
HorizontalScrollBarHeight = 17
CaptionHeight = 23
BorderSize = {Width=1, Height=1}
FixedFrameBorderSize = {Width=3, Height=3}
VerticalScrollBarThumbHeight = 17
HorizontalScrollBarThumbWidth = 17
IconSize = {Width=32, Height=32}
CursorSize = {Width=32, Height=32}
MenuFont = [Font: Name=Segoe UI, Size=12, Units=0, GdiCharSet=1, GdiVerticalFont=False]
MenuHeight = 20
PowerStatus = System.Windows.Forms.PowerStatus
WorkingArea = {X=0,Y=0,Width=1920,Height=1080}
KanjiWindowHeight = 0
MousePresent = True
VerticalScrollBarArrowHeight = 17
HorizontalScrollBarArrowWidth = 17
DebugOS = False
MouseButtonsSwapped = False
MinimumWindowSize = {Width=136, Height=39}
CaptionButtonSize = {Width=36, Height=22}
FrameBorderSize = {Width=4, Height=4}
MinWindowTrackSize = {Width=136, Height=39}
DoubleClickSize = {Width=4, Height=4}
DoubleClickTime = 500
IconSpacingSize = {Width=75, Height=75}
RightAlignedMenus = False
PenWindows = False
DbcsEnabled = False
MouseButtons = 8
Secure = False
Border3DSize = {Width=2, Height=2}
MinimizedWindowSpacingSize = {Width=160, Height=28}
SmallIconSize = {Width=16, Height=16}
ToolWindowCaptionHeight = 23
ToolWindowCaptionButtonSize = {Width=22, Height=22}
MenuButtonSize = {Width=19, Height=19}
ArrangeStartingPosition = Hide
ArrangeDirection = Left
MinimizedWindowSize = {Width=160, Height=28}
MaxWindowTrackSize = {Width=1940, Height=1100}
PrimaryMonitorMaximizedWindowSize = {Width=1936, Height=1096}
Network = True
TerminalServerSession = False
BootMode = Normal
DragSize = {Width=4, Height=4}
ShowSounds = False
MenuCheckSize = {Width=15, Height=15}
MidEastEnabled = False
NativeMouseWheelSupport = True
MouseWheelPresent = True
VirtualScreen = {X=0,Y=0,Width=1920,Height=1080}
MonitorCount = 1
MonitorsSameDisplayFormat = True
ComputerName = WZ1G89XBX
UserDomainName = LYZ
UserInteractive = True
UserName = pirklj
IsDropShadowEnabled = True
IsFlatMenuEnabled = True
IsFontSmoothingEnabled = True
FontSmoothingContrast = 1200
FontSmoothingType = 2
IconHorizontalSpacing = 75
IconVerticalSpacing = 75
IsIconTitleWrappingEnabled = True
MenuAccessKeysUnderlined = False
KeyboardDelay = 1
IsKeyboardPreferred = False
KeyboardSpeed = 31
MouseHoverSize = {Width=4, Height=4}
MouseHoverTime = 400
MouseSpeed = 10
IsSnapToDefaultEnabled = False
PopupMenuAlignment = Right
IsMenuFadeEnabled = True
MenuShowDelay = 400
IsComboBoxAnimationEnabled = True
IsTitleBarGradientEnabled = True
IsHotTrackingEnabled = True
IsListBoxSmoothScrollingEnabled = True
IsMenuAnimationEnabled = True
IsSelectionFadeEnabled = True
IsToolTipAnimationEnabled = True
UIEffectsEnabled = True
IsActiveWindowTrackingEnabled = False
ActiveWindowTrackingDelay = 0
IsMinimizeRestoreAnimationEnabled = False
BorderMultiplierFactor = 1
CaretBlinkTime = 530
CaretWidth = 1
MouseWheelScrollDelta = 120
VerticalFocusThickness = 1
HorizontalFocusThickness = 1
VerticalResizeBorderThickness = 4
HorizontalResizeBorderThickness = 4
ScreenOrientation = Angle0
SizingBorderWidth = 1
SmallCaptionButtonSize = {Width=22, Height=22}
MenuBarButtonSize = {Width=19, Height=19}

c# - How to format interpolated strings

This example writes double value with two decimal places.

double zoom = this.ZoomFactor * 100.0;
LStatusZoom.Text = $"Zoom: {zoom:0.##} %";

Output:

Zoom: 80.25 %

win os - How to copy all files defined by mask in all subdirectories into one directory

Copy all *.mobi files in current directory and all subdirectories into c:\temp\mobi directory. 

The destination directory must exists.

find . -name \*.mobi -exec cp {} c:/temp/mobi/ \;

UPDATE: Better variant:

for /r %i in (*.epub) do xcopy /Y "%i" c:\temp\mobi

c# - How to make DOWN button (in group of buttons)

The goal: Only one button from group can be down.

Every button link through Click event to this method:

private void downclick( object sender, EventArgs e ) {
  Button b = (Button)sender;

  /* if is down -> do nothing */
  if ( b.BackColor == Color.IndianRed ) return;

  /* set as down */
  b.BackColor = Color.IndianRed;

  /* deselect others */
  b.Parent.Controls
    .Cast<Control>()
    .Where( x => x is Button )
    .Cast<Button>()
    .Where( x => x != b )
    .ToList()
    .ForEach( x => x.BackColor = Color.WhiteSmoke );
}

So - pushed button = Color.IndianRed. If you want to know which button is down pushed:

  /* get down button */
  Button b = groupBox1.Controls
    .Cast<Control>()
    .Where( x => x is Button )
    .Cast<Button>()
    .Where( x => x.BackColor == Color.IndianRed )
    .ToList()
    .FirstOrDefault();
        
  MessageBox.Show( b.Text );
}

c# - How to create instance with string class name

String variable sClass contains for example Box.LayoutItem string. ParentObject and ParentID are optional constructor parameters.

var p = Activator.CreateInstance( Type.GetType( sClass ), parentObject, parentID );
LayoutItem p1 = (LayoutItem)p;
p1.Load( x );

c# - How to solve error "Sequence contains no elements" by Max() LINQ

This error occurs when the list is empty - no items are suitable for conditions.

int xCalc = _layoutManager.Items
  .Where( x=> x.ParentObject == this.ParentObject )
  .Where( x=> x.LayoutRelativePosition == LayoutRelativePositionEnum.RIGHT )
  .Where( x=> x.IDOrder < this.IDOrder )              
  .Max( x=> x.xCalc + x.heightCalc );

Above Max() version returns in that situation (no items) error "Sequence contains no elements". For solution you can use this format of the Max() function:

int xCalc = _layoutManager.Items
  .Where( x=> x.ParentObject == this.ParentObject )
  .Where( x=> x.LayoutRelativePosition == LayoutRelativePositionEnum.RIGHT )
  .Where( x=> x.IDOrder < this.IDOrder )
  .Select(x => x.xCalc + x.heightCalc )
  .DefaultIfEmpty()          
  .Max();

c# - How get last x chars from string by LINQ

One possibility (last 6 chars):

string s = "This is a text";
      
MessageBox.Show( s.Substring( s.Length - 6 ) );

Another possibility with LINQ support (last 6 chars):

string s = "This is a text";
      
MessageBox.Show( new string( s.TakeLast(6).ToArray() ) );

c# - How solve if Console.WriteLine() doesn`t work

In that situation you can try this replacement:

System.Diagnostics.Debug.WriteLine( sDescription );

c# - How to download file from the web as string

Useful for example for .xml downloading. 

Old (now obsolete method):

string str = "";
#pragma warning disable SYSLIB0014 // Type or member is obsolete
using( var wc = new WebClient() )
{
  str = wc.DownloadString( this.URL );
}
#pragma warning restore SYSLIB0014 // Type or member is obsolete

New method:

string str = "";
HttpClient client = new HttpClient();
using ( HttpResponseMessage response = client.GetAsync( this.URL ).Result )
{
  using ( HttpContent content = response.Content )
  {
    str = content.ReadAsStringAsync().Result;
  }
}

sql server - How to use IFF instead of CASE

Since 2012+ version can be used IFF statement (similar like DECODE() in Oracle):

select todate 
from pricedisctable
where
itemrelation = 'S-331-123-2056';

select IIF( todate='1900-01-01 00:00:00.000', null, todate ) 
from pricedisctable
where
itemrelation = 'S-331-123-2056';

Output: