![Core C# and .NET
Quick Reference
1. Data Types
Primitive Size Example
string 2 bytes/char s = âreferenceâ;
bool b = true;
char 2 bytes ch = âaâ;
byte 1 byte b = 0x78;
short 2 bytes Ival = 54;
int 4 bytes Ival = 540;
long 8 bytes ival = 5400;
float 4 bytes val = 54.0F;
double 8 bytes val = 54.0D;
decimal 16 bytes val = 54.0M;
2. Arrays
Declaration
int[] numArray = {1903, 1907, 1910};
int[] numArray = new int[3];
// 3 rows and 2 columns
int[ , ] nums = {{1907, 1990}, {1904, 1986}, {1910, 1980}};
Array Operations
Array.Sort(numArray); // sort ascending
// Sort begins at element 4 and sorts 10 elements
Array.Sort(numArray, 4,10);
// Use one array as a key and sort two arrays
string[] values = {âCaryâ, âGaryâ, âBarbaraâ};
string[] keys = {âGrantâ, âCooperâ, âStanwyckâ};
Array.Sort(keys, values);
// Clear elements in array (array, 1st
element, # elements)
Array.Clear(numArray, 0, numArray.Length);
// Copy elements from one array to another
Array.Copy(src, target, numelements);
3. String Operations
Method Description
Compare String.Compare(stra, strb, case, ci)
bool case â true for case insensitive
ci â new CultureInfo(âen-USâ)
returns: <0 if a<b, 0 if a=b, 1 if a>b
IndexOf str.IndexOf(val, start, num)
val â string to search for
start â where to begin in string
num â number of chars to search
returns (â1) if no match.
LastIndexOf Search from end of string.
Replace newstr= oldstr.Replace(âoldâ,ânewâ);
Split Char[] delim= {â â, â,â};
string w = âKim, Joanna Leslieâ;
// create array with three names
string[] names= w.Split(delim);
6. Formatting Numeric and Date Values
Format Item Syntax: {index[,alignment] [:format string]}
index â Specifies element in list of values to which format is applied.
alignment â Indicates minimum width (in characters) to display value.
format string â Contains the code that specifies the format of the displayed value.
Example: String.Format(âPrice is: {0:C2}â, 49.95); // output: Price is: $ 49.95
a. Numeric Formatting
Format
Specifier
Pattern Value Description
C or c {0:C2}, 1388.55 $ 1388.55 Currency.
D or d {0:D5}, 45 00045 Must be integer value.
E or e {0,9:E2}, 1388.55 1.39+E003 Must be floating point.
F or f {0,9:F2}, 1388.55 1388.55 Fixed Point representation.
N or n {0,9:N1}, 1388.55 1,388.6 Insert commas
P or p {0,9:P3}, .7865 78.650% Converts to percent.
R or r {0,9:R}, 3.14159 3.14159 Retains all decimal places.
X or x {0,9:X4}, 31 001f Converts to Hex
Example: CultureInfo ci = new CultureInfo("de-DE"); // German culture
string curdt = String.Format(ci,"{0:M}",DateTime.Now); // 29 Juni
b. DateTime Formatting: (January 19, 2005 16:05:20) en-US
Format Value Displayed Format Value Displayed
d 1/19/2005 Y or y January, 2005
D Wednesday, January
19, 2005
t 4:05 PM
f Wednesday, January
19, 2005 4:05:20 PM
T 4:05:20 PM
F Wednesday, January
19, 2005 4:05 PM
s 2005-01-19T16:05:20
g 1/19/2005 4:05 PM u 2005-01-19 16:05:20Z
G 1/19/2005 4:05:20 PM U Wednesday, January
19, 2005 21:05:20PM
M or m January 19
7. Using the System.Text.RegularExpressions.Regex class
string zipexp = @"d{5}((-|s)?d{4})?$";
string addr="W.44th St, New York, NY 10017-0233";
Match m = Regex.Match(addr,zipexp); // Static method
Regex zipRegex= new Regex(zipexp);
m= zipRegex.Match(addr); // Use Regex Object
Console.WriteLine(m.Value); // 10017-0233
Pattern Description Example
+ Match one or more occurrence ab+c matches abc, abbc
* Match zero or more occurrences ab*c matches ac, abbc
? Matches zero or one occurrence ab?c matches ac, abc
d D Match decimal digit or non-digit (D) dd matches 01, 55
w W Match any word character or non-char w equals [a-zA-Z0-9_]
s S Match whitespace or non-whitespace d*sd+ matches 246 98
[ ] Match any character in set [aeiou]n matches in, on
[^ ] Match any character not in set [^aeiou] matches r or 2
a | b Either a or b jpg|jpeg|gif matches .jpg
n r t New line, carriage return, tab
Method Description
Substring mystring.Substring(ndx, len)
string alpha = âabcdefâ;
// returns âcdefâ
string s= alpha.Substring(2);
// returns âdeâ
s = alpha.Substring(3,2);
ToCharArray Places selected characters in a string
in a char array:
String vowel = âaeiouâ;
// create array of 5 vowels
char[] c = vowel.ToCharArray();
// create array of âiâ and âoâ.
char[] c = vowel.ToCharArray(2,2);
4. System.Text.StringBuilder
Constructor
StringBuilder sb = new StringBuilder();
StringBuilder sb = new StringBuilder(mystring);
StringBuilder sb = new StringBuilder(mystring,capacity);
mystring â Initial value of StringBuilder object
capacity â Initial size (characters) of buffer.
Using StringBuilderMembers
decimal bmi = 22.2M;
int wt=168;
StringBuilder sb = new StringBuilder(âMy weight is â);
sb = sb.Append(wt); // can append number
sb= sb.Append(â and my bmi is â).Append(bmi);
// my weight is 168 and my bmi is 22.2
sb= sb.Replace(â22.2â,â22.4â);
string s = sb.ToString();
// Clear and set to new value
sb.Length=0;
sb.Append(âXanaduâ);
5. DateTime and TimeSpan
DateTime Constructor
DateTime(yr, mo, day)
DateTime(yr, mo, day, hr, min, sec)
DateTime bday = new DateTime(1964,12,20,11,2,0);
DateTime newyr= DateTime.Parse(â1/1/2005â);
DateTime currdt = DateTime.Now;
// also AddHours, AddMonths, AddYears
DateTime tomorrow = currdt.AddDays(1);
TimeSpan diff = currdt.Subtract(bday);
// 14795 days from 12/20/64 to 6/24/05
Console.WriteLine(â{0}â, diff.Days);
// TimeSpan(hrs, min, sec)
TimeSpan ts = new TimeSpan(6, 30, 10);
// also FromMinutes, FromHours, FromDays
TimeSpan ts = TimeSpan.FromSeconds(120);
TimeSpan ts = ts2 â ts1; // +,-,>,<,==, !=](https://image.slidesharecdn.com/corecsharpandnetquickreference-140707071941-phpapp02/85/Core-csharp-and-net-quick-reference-1-320.jpg)
![8. Using the C# Compiler at the Command Line
C:>csc /t:library /out:reslib.dll mysource.cs
csc /t:winexe /r:ctls1.dll /r:ctls2.dll winapp.cs
csc /keyfile:strongkey.snk secure.cs
Option Description
/addmodule Import metadata from a file that does
not contain a manifest.
/debug Tells compiler to emit debugging info.
/doc Specifies an XML documentation file
to be created during compilation.
/keyfile Specifies file containing key used to
create a strong named assembly.
/lib Specifies directory to search for
external referenced assemblies.
/out Name of compiled output file.
/reference (/r) Reference to an external assembly.
/resource Resource file to embed in output.
/target (/t) /t:exe /t:library /t:module /t:winexe
9. C# Language Fundamentals
Control Flow Statements
switch (expression)
{ case expression:
// statements
break / goto / return()
case ...
default:
// statements
break / goto / return()
}
expression may be
integer, string, or enum.
switch (genre)
{
case âvhsâ:
price= 10.00M;
break;
case âdvdâ:
price=16.00M;
break;
default:
price=12.00M:
break;
}
if (condition) {
// statements
} else {
// statements
}
if (genre==âvhsâ)
price=10.00M;
else if (genre==âdvdâ)
price=16.00M;
else price=12.00M;
Loop Constructs
while (condition)
{ body }
do { body }
while (condition);
while ( ct < 8)
{ tot += ct; ct++; }
do { tot += ct; ct++;}
while (ct < 8);
11. Delegates and Events
Delegates
[modifiers] delegate result-type delegate name ([parameter list]);
// (1) Define a delegate that calls method(s) having a single string parameter
public delegate void StringPrinter(string s);
// (2) Register methods to be called by delegate
StringPrinter prt = new StringPrinter(PrintLower);
prt += new StringPrinter(PrintUpper);
prt(âCopyright was obtained in 2005â); / / execute PrintLower and PrintUpper
Using Anonymous Methods with a Delegate
Rather than calling a method, a delegate encapsulates code that is executed:
prt = delegate(string s) { Console.WriteLine(s.ToLower()); };
prt += delegate(string s) { Console.WriteLine(s.ToUpper()); };
prt(âPrint this in lower and upper case.â);
Events
// class.event += new delegate(event handler method);
Button Total = new Button();
Total.Click += new EventHandler(GetTotal);
// Event Handler method must have signature specified by delegate
private void GetTotal( object sender, EventArgs e) {
Commonly used Control Events
Event Delegate
Click, MouseEnter
DoubleClick, MouseLeave
EventHandler( object sender, EventArgs e)
MouseDown, Mouseup,
MouseMove
MouseEventHandler(object sender,
MouseEventArgs e)
e.X, e.Y â x and y coordinates
e.Button â MouseButton.Left, Middle, Right
KeyUp, KeyDown KeyEventHandler(object sndr, KeyEventArgs e)
e.Handled â Indicates whether event is handled.
e.KeyCode â Keys enumeration, e.g., Keys.V
e.Modifiers â Indicates if Alt, Ctrl, or Shift key.
KeyPress KeyPressEventHandler(object sender,
KeyPressEventArgs e)
12. struct
[attribute][modifier] struct name [:interfaces] { struct-body}
Differences from class:
âą is a value type âą cannot inherit from a class or be inherited
âą fields cannot have initializer âą explicit constructor must have a parameter
13. enum (Enumerated Type)
enum enum Operations
enum Fabric: int {
cotton = 1,
silk = 2,
wool = 4,
rayon = 8
}
int cotNum = (int) Fabric.cotton; // 1
string cotName = Fabric.cotton.ToString(); // cotton
string s = Enum.GetName(typeof(Fabric),2); // silk
// Create instance of wool enum if it is valid
if(Enum.IsDefined(typeof(Fabric), âwoolâ) Fabric woolFab
= (Fabric)Enum.Parse(typeof(Fabric),âwoolâ);
Loop Constructs (Continued)
for (initializer;
termination condition;
iteration;)
{ // statements }
foreach (type identifier in
collection)
{ // statements }
for (int i=0;i<8;i++)
{
tot += i;
}
int[] ages = {27, 33, 44};
foreach(int age in ages)
{ tot += age; }
10. C# Class Definition
Class
[public | protected | internal | private]
[abstract | sealed | static]
class class name [:class/interfaces inherited from]
Constructor
[access modifier] class name (parameters) [:initializer]
initializer â base calls constructor in base class.
this calls constructor within class.
public class Shirt: Apparel {
public Shirt(decimal p, string v) : base(p,v)
{ constructor body }
Method
[access modifier]
[static | virtual | override | new | sealed | abstract ]
method name (parameter list) { body }
virtual â method can be overridden in subclass.
override â overrides virtual method in base class.
new â hides non-virtual method in base class.
sealed â prevents derived class from inheriting.
abstract â must be implemented by subclass.
Passing Parameters:
a. By default, parameters are passed by value.
b. Passing by reference: ref and out modifiers
string id= âgmâ; // caller initializes ref
int weight; // called method initializes
GetFactor(ref id, out weight);
// ... other code here
static void GetFactor(ref string id, out int wt)
{
if (id==âgmâ) wt = 454; else wt=1;
return;
}
Property
[modifier] <datatype> property name {
public string VendorName
{
get { return vendorName; }
set { vendorName = value; } // note value keyword
}](https://image.slidesharecdn.com/corecsharpandnetquickreference-140707071941-phpapp02/85/Core-csharp-and-net-quick-reference-2-320.jpg)
Core csharp and net quick reference
- 1. Core C# and .NET Quick Reference 1. Data Types Primitive Size Example string 2 bytes/char s = âreferenceâ; bool b = true; char 2 bytes ch = âaâ; byte 1 byte b = 0x78; short 2 bytes Ival = 54; int 4 bytes Ival = 540; long 8 bytes ival = 5400; float 4 bytes val = 54.0F; double 8 bytes val = 54.0D; decimal 16 bytes val = 54.0M; 2. Arrays Declaration int[] numArray = {1903, 1907, 1910}; int[] numArray = new int[3]; // 3 rows and 2 columns int[ , ] nums = {{1907, 1990}, {1904, 1986}, {1910, 1980}}; Array Operations Array.Sort(numArray); // sort ascending // Sort begins at element 4 and sorts 10 elements Array.Sort(numArray, 4,10); // Use one array as a key and sort two arrays string[] values = {âCaryâ, âGaryâ, âBarbaraâ}; string[] keys = {âGrantâ, âCooperâ, âStanwyckâ}; Array.Sort(keys, values); // Clear elements in array (array, 1st element, # elements) Array.Clear(numArray, 0, numArray.Length); // Copy elements from one array to another Array.Copy(src, target, numelements); 3. String Operations Method Description Compare String.Compare(stra, strb, case, ci) bool case â true for case insensitive ci â new CultureInfo(âen-USâ) returns: <0 if a<b, 0 if a=b, 1 if a>b IndexOf str.IndexOf(val, start, num) val â string to search for start â where to begin in string num â number of chars to search returns (â1) if no match. LastIndexOf Search from end of string. Replace newstr= oldstr.Replace(âoldâ,ânewâ); Split Char[] delim= {â â, â,â}; string w = âKim, Joanna Leslieâ; // create array with three names string[] names= w.Split(delim); 6. Formatting Numeric and Date Values Format Item Syntax: {index[,alignment] [:format string]} index â Specifies element in list of values to which format is applied. alignment â Indicates minimum width (in characters) to display value. format string â Contains the code that specifies the format of the displayed value. Example: String.Format(âPrice is: {0:C2}â, 49.95); // output: Price is: $ 49.95 a. Numeric Formatting Format Specifier Pattern Value Description C or c {0:C2}, 1388.55 $ 1388.55 Currency. D or d {0:D5}, 45 00045 Must be integer value. E or e {0,9:E2}, 1388.55 1.39+E003 Must be floating point. F or f {0,9:F2}, 1388.55 1388.55 Fixed Point representation. N or n {0,9:N1}, 1388.55 1,388.6 Insert commas P or p {0,9:P3}, .7865 78.650% Converts to percent. R or r {0,9:R}, 3.14159 3.14159 Retains all decimal places. X or x {0,9:X4}, 31 001f Converts to Hex Example: CultureInfo ci = new CultureInfo("de-DE"); // German culture string curdt = String.Format(ci,"{0:M}",DateTime.Now); // 29 Juni b. DateTime Formatting: (January 19, 2005 16:05:20) en-US Format Value Displayed Format Value Displayed d 1/19/2005 Y or y January, 2005 D Wednesday, January 19, 2005 t 4:05 PM f Wednesday, January 19, 2005 4:05:20 PM T 4:05:20 PM F Wednesday, January 19, 2005 4:05 PM s 2005-01-19T16:05:20 g 1/19/2005 4:05 PM u 2005-01-19 16:05:20Z G 1/19/2005 4:05:20 PM U Wednesday, January 19, 2005 21:05:20PM M or m January 19 7. Using the System.Text.RegularExpressions.Regex class string zipexp = @"d{5}((-|s)?d{4})?$"; string addr="W.44th St, New York, NY 10017-0233"; Match m = Regex.Match(addr,zipexp); // Static method Regex zipRegex= new Regex(zipexp); m= zipRegex.Match(addr); // Use Regex Object Console.WriteLine(m.Value); // 10017-0233 Pattern Description Example + Match one or more occurrence ab+c matches abc, abbc * Match zero or more occurrences ab*c matches ac, abbc ? Matches zero or one occurrence ab?c matches ac, abc d D Match decimal digit or non-digit (D) dd matches 01, 55 w W Match any word character or non-char w equals [a-zA-Z0-9_] s S Match whitespace or non-whitespace d*sd+ matches 246 98 [ ] Match any character in set [aeiou]n matches in, on [^ ] Match any character not in set [^aeiou] matches r or 2 a | b Either a or b jpg|jpeg|gif matches .jpg n r t New line, carriage return, tab Method Description Substring mystring.Substring(ndx, len) string alpha = âabcdefâ; // returns âcdefâ string s= alpha.Substring(2); // returns âdeâ s = alpha.Substring(3,2); ToCharArray Places selected characters in a string in a char array: String vowel = âaeiouâ; // create array of 5 vowels char[] c = vowel.ToCharArray(); // create array of âiâ and âoâ. char[] c = vowel.ToCharArray(2,2); 4. System.Text.StringBuilder Constructor StringBuilder sb = new StringBuilder(); StringBuilder sb = new StringBuilder(mystring); StringBuilder sb = new StringBuilder(mystring,capacity); mystring â Initial value of StringBuilder object capacity â Initial size (characters) of buffer. Using StringBuilderMembers decimal bmi = 22.2M; int wt=168; StringBuilder sb = new StringBuilder(âMy weight is â); sb = sb.Append(wt); // can append number sb= sb.Append(â and my bmi is â).Append(bmi); // my weight is 168 and my bmi is 22.2 sb= sb.Replace(â22.2â,â22.4â); string s = sb.ToString(); // Clear and set to new value sb.Length=0; sb.Append(âXanaduâ); 5. DateTime and TimeSpan DateTime Constructor DateTime(yr, mo, day) DateTime(yr, mo, day, hr, min, sec) DateTime bday = new DateTime(1964,12,20,11,2,0); DateTime newyr= DateTime.Parse(â1/1/2005â); DateTime currdt = DateTime.Now; // also AddHours, AddMonths, AddYears DateTime tomorrow = currdt.AddDays(1); TimeSpan diff = currdt.Subtract(bday); // 14795 days from 12/20/64 to 6/24/05 Console.WriteLine(â{0}â, diff.Days); // TimeSpan(hrs, min, sec) TimeSpan ts = new TimeSpan(6, 30, 10); // also FromMinutes, FromHours, FromDays TimeSpan ts = TimeSpan.FromSeconds(120); TimeSpan ts = ts2 â ts1; // +,-,>,<,==, !=
- 2. 8. Using the C# Compiler at the Command Line C:>csc /t:library /out:reslib.dll mysource.cs csc /t:winexe /r:ctls1.dll /r:ctls2.dll winapp.cs csc /keyfile:strongkey.snk secure.cs Option Description /addmodule Import metadata from a file that does not contain a manifest. /debug Tells compiler to emit debugging info. /doc Specifies an XML documentation file to be created during compilation. /keyfile Specifies file containing key used to create a strong named assembly. /lib Specifies directory to search for external referenced assemblies. /out Name of compiled output file. /reference (/r) Reference to an external assembly. /resource Resource file to embed in output. /target (/t) /t:exe /t:library /t:module /t:winexe 9. C# Language Fundamentals Control Flow Statements switch (expression) { case expression: // statements break / goto / return() case ... default: // statements break / goto / return() } expression may be integer, string, or enum. switch (genre) { case âvhsâ: price= 10.00M; break; case âdvdâ: price=16.00M; break; default: price=12.00M: break; } if (condition) { // statements } else { // statements } if (genre==âvhsâ) price=10.00M; else if (genre==âdvdâ) price=16.00M; else price=12.00M; Loop Constructs while (condition) { body } do { body } while (condition); while ( ct < 8) { tot += ct; ct++; } do { tot += ct; ct++;} while (ct < 8); 11. Delegates and Events Delegates [modifiers] delegate result-type delegate name ([parameter list]); // (1) Define a delegate that calls method(s) having a single string parameter public delegate void StringPrinter(string s); // (2) Register methods to be called by delegate StringPrinter prt = new StringPrinter(PrintLower); prt += new StringPrinter(PrintUpper); prt(âCopyright was obtained in 2005â); / / execute PrintLower and PrintUpper Using Anonymous Methods with a Delegate Rather than calling a method, a delegate encapsulates code that is executed: prt = delegate(string s) { Console.WriteLine(s.ToLower()); }; prt += delegate(string s) { Console.WriteLine(s.ToUpper()); }; prt(âPrint this in lower and upper case.â); Events // class.event += new delegate(event handler method); Button Total = new Button(); Total.Click += new EventHandler(GetTotal); // Event Handler method must have signature specified by delegate private void GetTotal( object sender, EventArgs e) { Commonly used Control Events Event Delegate Click, MouseEnter DoubleClick, MouseLeave EventHandler( object sender, EventArgs e) MouseDown, Mouseup, MouseMove MouseEventHandler(object sender, MouseEventArgs e) e.X, e.Y â x and y coordinates e.Button â MouseButton.Left, Middle, Right KeyUp, KeyDown KeyEventHandler(object sndr, KeyEventArgs e) e.Handled â Indicates whether event is handled. e.KeyCode â Keys enumeration, e.g., Keys.V e.Modifiers â Indicates if Alt, Ctrl, or Shift key. KeyPress KeyPressEventHandler(object sender, KeyPressEventArgs e) 12. struct [attribute][modifier] struct name [:interfaces] { struct-body} Differences from class: âą is a value type âą cannot inherit from a class or be inherited âą fields cannot have initializer âą explicit constructor must have a parameter 13. enum (Enumerated Type) enum enum Operations enum Fabric: int { cotton = 1, silk = 2, wool = 4, rayon = 8 } int cotNum = (int) Fabric.cotton; // 1 string cotName = Fabric.cotton.ToString(); // cotton string s = Enum.GetName(typeof(Fabric),2); // silk // Create instance of wool enum if it is valid if(Enum.IsDefined(typeof(Fabric), âwoolâ) Fabric woolFab = (Fabric)Enum.Parse(typeof(Fabric),âwoolâ); Loop Constructs (Continued) for (initializer; termination condition; iteration;) { // statements } foreach (type identifier in collection) { // statements } for (int i=0;i<8;i++) { tot += i; } int[] ages = {27, 33, 44}; foreach(int age in ages) { tot += age; } 10. C# Class Definition Class [public | protected | internal | private] [abstract | sealed | static] class class name [:class/interfaces inherited from] Constructor [access modifier] class name (parameters) [:initializer] initializer â base calls constructor in base class. this calls constructor within class. public class Shirt: Apparel { public Shirt(decimal p, string v) : base(p,v) { constructor body } Method [access modifier] [static | virtual | override | new | sealed | abstract ] method name (parameter list) { body } virtual â method can be overridden in subclass. override â overrides virtual method in base class. new â hides non-virtual method in base class. sealed â prevents derived class from inheriting. abstract â must be implemented by subclass. Passing Parameters: a. By default, parameters are passed by value. b. Passing by reference: ref and out modifiers string id= âgmâ; // caller initializes ref int weight; // called method initializes GetFactor(ref id, out weight); // ... other code here static void GetFactor(ref string id, out int wt) { if (id==âgmâ) wt = 454; else wt=1; return; } Property [modifier] <datatype> property name { public string VendorName { get { return vendorName; } set { vendorName = value; } // note value keyword }