<div>
    <h4 class="text-primary pt-3">Attribute Splatting Child Component</h4>

    <input id="roomName"
        placeholder="@Placeholder"
        required="@Required"
        maxlength="@MaxLength"
        class="form-control" />
</div>

@code {
    [Parameter]
    public string Placeholder { get; set; } = "Initial Text";

    [Parameter]
    public string Required { get; set; } = "required";

    [Parameter]
    public string MaxLength { get; set; } = "10";
}

@page "/AttributeSplatting"

<h1>Attribute Splatting</h1>

<AttributeSplattingChild
    Placeholder="Enter the Room Name From Parent"
    MaxLength="5">
</AttributeSplattingChild>

<div>
    <h4 class="text-primary pt-3">Attribute Splatting Child Component</h4>

    <input id="roomName" @attributes="InputAttributes" class="form-control" />
</div>

@code {
    [Parameter]
    public Dictionary<string, object> InputAttributes { get; set; } = new Dictionary<string, object>
    {
        { "required" , "required"},
        { "placeholder", "Initial Text"},
        { "maxlength", 10}
    };
}

@page "/AttributeSplatting"

<h1>Attribute Splatting</h1>

<AttributeSplattingChild InputAttributes="InputAttributesFromParent"></AttributeSplattingChild>

@code{
    Dictionary<string, object> InputAttributesFromParent = new Dictionary<string, object>
    {
        { "required" , "required"},
        { "placeholder", "Enter the Room Name From Parent"},
        { "maxlength", 5}
    };
}

<div>
    <h4 class="text-primary pt-3">Attribute Splatting Child Component</h4>

    <input id="roomName" @attributes="InputAttributes" placeholder="Initial Text" class="form-control" />
</div>

@code {
    [Parameter(CaptureUnmatchedValues = true)]
    public Dictionary<string, object> InputAttributes { get; set; } = new Dictionary<string, object>();
}

@page "/AttributeSplatting"

<h1>Attribute Splatting</h1>

<AttributeSplattingChild placeholder="Placeholder default"></AttributeSplattingChild>

<input id="roomName" placeholder="Initial Text" @attributes="InputAttributes" class="form-control" />

<div class="row">
    <h4 class="text-primary pl-4 pt-2 col-12">Grand Child Component</h4>
    <br />
    <p> There is a message - @MessageForGrandChild </p>
</div>

@code {
    [Parameter]
    public string MessageForGrandChild { get; set; }
}

<div class="mt-2">
    <GrandChildComponent MessageForGrandChild="@MessageForGrandChild"></GrandChildComponent>
</div>


@code {
    [Parameter]
    public string MessageForGrandChild { get; set; }

   // ...
}

<ChildComponent
    MessageForGrandChild="This is a message from Grand Parent"
    Title="This is the second child component">
    <p><b>@MessageText</b></p>
</ChildComponent>

<CascadingValue Value="@MessageForGrandChild">
    <ChildComponent        
        Title="This is the second child component">
        <p><b>@MessageText</b></p>
    </ChildComponent>
</CascadingValue>

@code {
    string MessageForGrandChild = "This is a message from Grand Parent";

<GrandChildComponent></GrandChildComponent>

[CascadingParameter]
public string MessageForGrandChild { get; set; }

<CascadingValue Value="@MessageForGrandChild" Name="MessageFromGrandParent">
    <CascadingValue Value="@Number" Name="GrandParentsNumber">
        <ChildComponent
            Title="This is the second child component">
            <p><b>@MessageText</b></p>
        </ChildComponent>
    </CascadingValue>
</CascadingValue>

@code {
    string MessageForGrandChild = "This is a message from Grand Parent";
    int Number = 7;

<div class="row">
    <h4 class="text-primary pl-4 pt-2 col-12">Grand Child Component</h4>
    <br />
    There is a message: @Message
    <br />
    GrandParentsNumber: @Number
</div>

@code {
    [CascadingParameter(Name = "MessageFromGrandParent")]
    public string Message { get; set; }

    [CascadingParameter(Name = "GrandParentsNumber")]
    public int Number { get; set; }
}

کدهای متورم (Bloaters) 

بد استفاده کنندگان از شیء گرایی (Object orientation abusers)  

جلوگیری کنندگان از تغییر(Change preventers) 

کدهای غیر ضروری (Dispensables) 

کدهایی بیش از اندازه وابسته به هم (Couplers) 

 CREATE TABLE xmlTest
(
 id INT IDENTITY PRIMARY KEY,
 doc XML
)
GO
INSERT xmlTest VALUES('<Person name="Vahid" />')
INSERT xmlTest VALUES('<Person name="Farid" />')
INSERT xmlTest VALUES('<Person name="Mehdi" /><Person name="Hamid" />')
GO

 SELECT doc.query('
for $p in //Person
where $p/@name="Vahid"
return <li>{data($p/@name)} has id = {sql:column("xmlTest.id")}</li>
')
FROM xmlTest

 <li>Vahid has id = 1</li>

 SELECT doc.query('
for $p in //Person
where $p/@name="Vahid"
return <li>{data($p/@name)} has id = {sql:column("xmlTest.id")}</li>
')
FROM xmlTest
WHERE doc.exist('
for $p in //Person
where $p/@name="Vahid"
return <li>{data($p/@name)} has id = {sql:column("xmlTest.id")}</li>
')=1

 SELECT * FROM
(
 (SELECT doc.query('
 for $p in //Person
 where $p/@name="Vahid"
 return <li>{data($p/@name)} has id = {sql:column("xmlTest.id")}</li>
 ') AS col1
 FROM xmlTest)
) A
WHERE CONVERT(VARCHAR(8000), col1)<>''

 DECLARE @number INT = 1
SELECT doc.query('
for $p in //Person
where $p/@name="Vahid"
return <li>{data($p/@name)} has number = {sql:variable("@number")}</li>
')
FROM xmlTest

 SELECT doc.query('/Person') FROM xmlTest

 DECLARE @doc XML
SET @doc = (SELECT * FROM xmlTest FOR XML AUTO, ELEMENTS)
SELECT @doc.query('/xmlTest/doc/Person')

 DECLARE @doc XML ='
<people>
  <person><name>Vahid</name></person>
  <person><name id="2">Farid</name></person>
  <person><name>Mehdi</name></person>
  <person><name>Hooshang</name><name id="1">Hooshi</name></person>
  <person></person>
</people>
'

 SELECT @doc.value('/people/person/name', 'varchar(50)')

 SELECT @doc.value('(/people/person/name)[1]', 'varchar(50)')

 SELECT @doc.query('/people/person/name')

 <name>Vahid</name>
<name id="2">Farid</name>
<name>Mehdi</name>
<name>Hooshang</name>
<name id="1">Hooshi</name>

 SELECT
tab.col.value('text()[1]', 'varchar(50)') AS name,
tab.col.query('.'),
tab.col.query('..')
from @doc.nodes('/people/person/name') AS tab(col)

 tab.col.query('.'),

 SELECT
tab.col.value('.', 'varchar(50)') AS name,
tab.col.query('data(.)'),
tab.col.query('.'),
tab.col.query('..')
from @doc.nodes('/people/person/name') AS tab(col)

 SELECT
tab.col.value('name[.="Farid"][1]', 'varchar(50)') AS name,
tab.col.value('name[.="Farid"][1]/@id', 'varchar(50)') AS id,
tab.col.query('.')
from @doc.nodes('/people/person[name="Farid"]') AS tab(col)

 DECLARE @tblXML TABLE (
 id INT IDENTITY PRIMARY KEY,
 doc XML
 )

INSERT @tblXML VALUES('<person name="Vahid" />')
INSERT @tblXML VALUES('<person name="Farid" />')
INSERT @tblXML VALUES('<person />')
INSERT @tblXML VALUES(NULL)

SELECT
id,
doc.value('(/person/@name)[1]', 'varchar(50)') AS name
FROM @tblXML

 CREATE PROCEDURE LookForPhysicalOps (@op VARCHAR(30))
AS
SELECT sql.text, qs.EXECUTION_COUNT, qs.*, p.*
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_sql_text(sql_handle) sql
CROSS APPLY sys.dm_exec_query_plan(plan_handle) p
WHERE query_plan.exist('
declare default element namespace "http://schemas.microsoft.com/sqlserver/2004/07/showplan";
/ShowPlanXML/BatchSequence/Batch/Statements//RelOp/@PhysicalOp[. = sql:variable("@op")]
') = 1
GO

EXECUTE LookForPhysicalOps 'Table Scan'
EXECUTE LookForPhysicalOps 'Clustered Index Scan'
EXECUTE LookForPhysicalOps 'Hash Match'

 WITH XMLNAMESPACES(DEFAULT N'http://schemas.microsoft.com/sqlserver/2004/07/showplan')
SELECT RelOp.op.value(N'../../@NodeId', N'int') AS ParentOperationID,
RelOp.op.value(N'@NodeId', N'int') AS OperationID,
RelOp.op.value(N'@PhysicalOp', N'varchar(50)') AS PhysicalOperator,
RelOp.op.value(N'@LogicalOp', N'varchar(50)') AS LogicalOperator,
RelOp.op.value(N'@EstimatedTotalSubtreeCost ', N'float') AS EstimatedCost,
RelOp.op.value(N'@EstimateIO', N'float') AS EstimatedIO,
RelOp.op.value(N'@EstimateCPU', N'float') AS EstimatedCPU,
RelOp.op.value(N'@EstimateRows', N'float') AS EstimatedRows,
cp.plan_handle AS PlanHandle,
st.TEXT AS QueryText,
qp.query_plan AS QueryPlan,
cp.cacheobjtype AS CacheObjectType,
cp.objtype AS ObjectType
FROM sys.dm_exec_cached_plans cp
CROSS APPLY sys.dm_exec_sql_text(cp.plan_handle) st
CROSS APPLY sys.dm_exec_query_plan(cp.plan_handle) qp
CROSS APPLY qp.query_plan.nodes(N'//RelOp') RelOp(op)

DECLARE @doc XML = '
<Invoice>
<InvoiceId>100</InvoiceId>
<CustomerName>Vahid</CustomerName>
<LineItems>
<LineItem>
<Sku>134</Sku>
<Quantity>10</Quantity>
<Description>Item 1</Description>
<UnitPrice>9.5</UnitPrice>
</LineItem>
<LineItem>
<Sku>150</Sku>
<Quantity>5</Quantity>
<Description>Item 2</Description>
<UnitPrice>1.5</UnitPrice>
</LineItem>
</LineItems>
</Invoice>
'

 SET @doc.modify('
insert <InvoiceInfo><InvoiceDate>2014-02-10</InvoiceDate></InvoiceInfo>
after /Invoice[1]/CustomerName[1]
')

SELECT @doc

<Invoice>
  <InvoiceId>100</InvoiceId>
  <CustomerName>Vahid</CustomerName>
  <InvoiceInfo>
        <InvoiceDate>2014-02-10</InvoiceDate>
  </InvoiceInfo>
  <LineItems>
...

 SET @x.modify('insert sql:variable("@x") into /doc[1]')

 The argument 1 of the XML data type method "modify" must be a string literal.

 SET @doc.modify('
insert attribute status{"backorder"}
into /Invoice[1]
')

SELECT @doc

 <Invoice status="backorder">
  <InvoiceId>100</InvoiceId>
....

 SET @doc.modify('delete /Invoice/LineItems/LineItem')
SELECT @doc

 <Invoice status="backorder">
  <InvoiceId>100</InvoiceId>
  <CustomerName>Vahid</CustomerName>
  <InvoiceInfo>
      <InvoiceDate>2014-02-10</InvoiceDate>
  </InvoiceInfo>
  <LineItems />
</Invoice>

 SET @doc.modify('replace value of
  /Invoice[1]/CustomerName[1]/text()[1]
  with "Farid"
')
SELECT @doc

 <Invoice status="backorder">
  <InvoiceId>100</InvoiceId>
  <CustomerName>Farid</CustomerName>
  <InvoiceInfo>
       <InvoiceDate>2014-02-10</InvoiceDate>
  </InvoiceInfo>
  <LineItems />
</Invoice>

 The target of 'replace value of' must be a non-metadata attribute or an element with simple typed content.

 DECLARE @tblTest AS TABLE (xmlField XML)

INSERT INTO @tblTest(xmlField)
VALUES
 (
'<Sample>
   <Node1>Value1</Node1>
   <Node2>Value2</Node2>
   <Node3/>
</Sample>'
)
 
DECLARE @newValue VARCHAR(50) = 'NewValue'

UPDATE @tblTest
SET xmlField.modify(
'insert text{sql:variable("@newValue")} into
  (/Sample/Node3)[1] [not(text())]'
)

SELECT xmlField.value('(/Sample/Node3)[1]','varchar(50)') FROM @tblTest

 UPDATE @tblTest
SET xmlField.modify(
'replace value of (/Sample/Node3/text())[1]
  with sql:variable("@newValue")'
)

public class Rectangle
{
    public int Length { get; set; }
    public int Height { get; set; }

    public void Grow(int length, int height)
    {
        Length += length;
        Height += height;
    }
}

Rectangle r = new Rectangle();
r.Length = 5;
r.Height = 10;
r.Grow(10, 10);// r.Length is 15, r.Height is 20, same instance of r

// After
public class ImmutableRectangle
{
    int Length { get; }
    int Height { get; }

    public ImmutableRectangle(int length, int height)
    {
        Length = length;
        Height = height;
    }

    public ImmutableRectangle Grow(int length, int height) =>
          new ImmutableRectangle(Length + length, Height + height);
}

ImmutableRectangle r = new ImmutableRectangle(5, 10);
r = r.Grow(10, 10);// r.Length is 15, r.Height is 20, is a new instance of r

public static void Main()
{
    Console.WriteLine(GetSalutation(DateTime.Now.Hour));
}

// imparitive, mutates state to produce a result
/*public static string GetSalutation(int hour)
{
    string salutation; // placeholder value

    if (hour < 12)
        salutation = "Good Morning";
    else
        salutation = "Good Afternoon";

    return salutation; // return mutated variable
}*/

public static string GetSalutation(int hour) => hour < 12 ? "Good Morning" : "Good Afternoon";

public static int Count<TSource>(this IEnumerable<TSource> source, Func<TSource, bool> predicate)
{
    int count = 0;

    foreach (TSource element in source)
    {
        checked
        {
            if (predicate(element))
            {
                count++;
            }
        }
    }

    return count;
}

public static class Extensions
{
    public static Func<T, TReturn2> Compose<T, TReturn1, TReturn2>(this Func<TReturn1, TReturn2> func1, Func<T, TReturn1> func2)
    {
        return x => func1(func2(x));
    }
}

public class Program
{
    public static void Main(string[] args)
    {
        Func<int, int> square = (x) => x * x;
        Func<int, int> negate = x => x * -1;
        Func<int, string> toString = s => s.ToString();
        Func<int, string> squareNegateThenToString = toString.Compose(negate).Compose(square);
        Console.WriteLine(squareNegateThenToString(2));
    }
}

string str = new StringBuilder()
  .Append("Hello ")
  .Append("World ")
  .ToString()
  .TrimEnd()
  .ToUpper();

public static class Extensions
{
    public static StringBuilder AppendWhen(this StringBuilder sb, string value, bool predicate) => predicate ? sb.Append(value) : sb;
}

public class Program
{
    public static void Main(string[] args)
    {
        // Extends the StringBuilder class to accept a predicate
        string htmlButton = new StringBuilder().Append("<button").AppendWhen(" disabled", false).Append(">Click me</button>").ToString();
    }
}

public static void Main()
{
    int[] a = { 1, 2, 3, 4, 5 };

    foreach (int n in GreaterThan(a, 3))
    {
        Console.WriteLine(n);
    }
}


/*public static IEnumerable<int> GreaterThan(int[] arr, int gt)
{
    List<int> temp = new List<int>();
    foreach (int n in arr)
    {
        if (n > gt) temp.Add(n);
    }
    return temp;
}*/

public static IEnumerable<int> GreaterThan(int[] arr, int gt)
{
    foreach (int n in arr)
    {
        if (n > gt) yield return n;
    }
}

List<int> collection = new List<int> { 1, 2, 3, 4, 5 };

// Imparative style of programming is verbose
List<int> results = new List<int>();

foreach(var num in collection)
{
  if (num % 2 != 0) results.Add(num);
}

// Declarative is terse and beautiful
var results = collection.Where(num => num % 2 != 0);

private void A ( [CallerMemberName] string callerName = "") 
{
  Console.WriteLine("Caller is " + callerName);
}

private static void B()
{
        // let's call A
        A();
}

    public class PersonViewModel : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        private void OnPropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }

        private string name;
        public string Name
        {
            get { return name; }
            set
            {
                this.name = value;
                OnPropertyChanged("Name");
            }
        }
    }

private string firstName;
public string FirstName
{
            get { return firstName; }
            set
            {
                this.firstName = value;
                OnPropertyChanged("Name");
            }
}

public abstract class ViewModelBase : INotifyPropertyChanged
{
        public event PropertyChangedEventHandler PropertyChanged;

        protected void OnPropertyChanged([CallerMemberName] string propertyName = "")
        {
            OnPropertyChangedExplicit(propertyName);
        }

        protected void OnPropertyChanged<TProperty>(Expression<Func<TProperty>> projection)
        {
            var memberExpression = (MemberExpression)projection.Body;
            OnPropertyChangedExplicit(memberExpression.Member.Name);
        }

        void OnPropertyChangedExplicit(string propertyName)
        {
            this.CheckPropertyName(propertyName);

            PropertyChangedEventHandler handler = this.PropertyChanged;

            if (handler != null)
            {
                var e = new PropertyChangedEventArgs(propertyName);
                handler(this, e);
            }
        }

        #region Check property name

        [Conditional("DEBUG")]
        [DebuggerStepThrough]
        public void CheckPropertyName(string propertyName)
        {
            if (TypeDescriptor.GetProperties(this)[propertyName] == null)
                throw new Exception(String.Format("Could not find property \"{0}\"", propertyName));
        }

        #endregion // Check property name
}

public class PersonViewModel : ViewModelBase
{
        private string firstName;
        public string FirstName
        {
            get { return firstName; }
            set
            {
                this.firstName = value;

                OnPropertyChanged();
                OnPropertyChanged(() => this.FullName);
            }
        }

        private string lastName;
        public string LastName
        {
            get { return lastName; }
            set
            {
                this.lastName = value;

                OnPropertyChanged();
                OnPropertyChanged(() => this.FullName);
            }
        }

        public string FullName
        {
            get { return string.Format("{0} {1}", FirstName, LastName); }
        }
}